#specimen grinding and polishing machine

[hsmleindia]

Metallographic Specimen Grinding And Polishing Machine

Metallographic specimen grinding and polishing machine is equipped with double discs and features step-less speed changing for grinding and polishing. It can finish the whole process of rough grinding, fine grinding, rough polishing, and finishing polishing for specimen preparation. By adjusting the transducer, it can realize the rotating speed of the grinding and polishing disc adjustable from 50 to 1000 rpm.

[albonium]

why do home appliances not have big red emergency buttons like lab equipment does. what do i do if i have to stop my washing machine or oven ???? just put one of these on the side

[carnegiemuseumnaturalhistory]

Diamonds Are the World’s Best Friend: The Important Roles Diamonds Play in Society

by Shelby Wyzykowski

In the classic 1953 movie “Gentlemen Prefer Blondes” is a memorable musical number performed by silver screen legend Marilyn Monroe. Wearing a striking pink satin gown and dripping in dazzling jewels, she is surrounded on the stage by a bevy of handsome suitors that are dressed to the nines. In this glamorous setting, she sings the praises of diamonds…how nothing in the world can compare to how it feels to possess these glittering gemstones. But off-screen, Monroe’s taste in brilliant baubles was radically different, preferring costume jewelry to the real thing. I have to admit that I agree with Marilyn. Diamonds have never held much interest for me. That is until now. After doing a little research, I’ve discovered that, besides their use in the jewelry industry, there are other ways in which diamonds are utilized in society today. In fact, there is so much more to these captivating stones than just their scintillating sparkle.

Perhaps you’ve heard the adage “one person’s trash is another person’s treasure.” Well, it just might surprise you that this saying holds true for diamonds. In the jewelry world, a diamond with perfect clarity is the much-desired ideal. But in the scientific world, a so-called “poor” specimen that is full of inclusions (imperfections), could hold a treasure trove of geologic information. Researchers are studying them to try and uncover the secrets of the deep-Earth environment. The majority of diamonds are created fairly close to the Earth’s surface, between 93 and 150 miles down. But there are some diamonds, called super-deep diamonds, that come from far down in the Earth’s mantle and are as deep as 500 to 600 miles (the mantle, which is mostly made up of solid and very hot rock, is directly below the Earth’s surface layer, or crust, and makes up more than 80 percent of our planet’s volume). These 3.5 billion-year-old gems formed at a pressure that is 240,000 times the atmospheric pressure at sea level, and this fact makes these tiny stone time capsules extremely valuable to researchers. No doubt geologists would love to travel deep under our planet’s surface like the characters in Jules Verne’s 1864 science fiction novel Journey to the Center of the Earth. Unfortunately they can’t, but these super-deep diamonds are the next best thing to journeying there themselves!

With these diamonds, scientists are uncovering clues to the origins of water on Earth. Did water come from incoming asteroids and comets, or was water an integral component at the planet’s formation? We’re still not quite sure. But diamond research has brought us closer to figuring out how much water lies deep underground. Scientists think that there may in fact be as much water present in our planet’s deep subsurface as there is found in our oceans. They have developed this idea after discovering a special water encased in the inclusions of deep diamonds. Called ICE-VII, this water ice can only be formed under tremendous deep-Earth pressure. In addition to water, geologists have found an elusive mineral in diamond inclusions. Scientists had theorized it to be an extremely common mineral that makes up to 38 percent of the Earth’s volume, but it’s been impossible to create in a lab. Now that it’s been found in nature, researchers have the proof of its existence and have named it Silicate-Perovskite (or Bridgmanite). In addition to Bridgmanite, they have discovered other trace minerals and elements that are commonly present in the Earth’s crust. This means that the materials were subducted (drawn back down into the Earth) billions of years ago by plate tectonics. Deep in the mantle, the materials were encased in a forming deep-diamond and then eventually sent back up to the surface by way of volcanic eruptions. Even more exciting than all of these discoveries is the thought of what geologists still have yet to uncover. They still hope to find carbon from primordial organic matter in these special diamonds. That matter could be a clue to the origins of life on Earth!

"Earth’s most abundant mineral finally has a name" byArgonne National Laboratory is licensed under CC BY-NC-SA 2.0

In addition to their contributions to the scientific field, diamonds also have practical uses in society. In the mid-1950’s, synthetic diamonds were invented. Created in a lab, they are chemically and physically exactly the same as natural diamonds. However, these man-made gems do not possess the allure and mystery of natural diamonds, so they are not very desirable in the jewelry market. But since diamonds are the hardest known natural substance, they are ideal for industrial use. For example, they can be pulverized into a fine abrasive that can be made into a “diamond paste” and used for polishing other jewelry-grade gemstones. Small particles of diamond can also be embedded in tools like saw blades, drill bits, and grinding wheels. These diamond-coated tools are very wear-resistant and can be used for mining, deep-sea drilling, and road construction. And there are some ingenious uses for diamonds that you may find to be very surprising. Diamond windows can be made from very thin (thinner than a human hair) diamond membranes. These windows cover X-ray machines, laser openings, and vacuum chambers. A diamond can also make your music sound better. A speaker dome made out of diamonds can vibrate very rapidly because this gem is such a stiff material. So it is ideal for enhancing the performance of high-quality speakers. Diamonds can even help you keep track of time. Small mechanical devices, such as watches, have tiny bearings inside of them that make everything move (in a watch, it’s called its “movement”). A thin coating of diamond makes these parts wear-resistant and ensures accurate time-telling and lasting durability. From helping to build highways to making your timepiece tick, who knew that diamonds could be so useful in so many ways!

CM18561 is located in the Native Elements case in Hillman Hall of Minerals and Gems. Source: https://carnegiemnh.org/emu_widgets/mineralogy.html#details=ecatalogue.2019718

Yet another important role that diamonds have played in our world is how they have influenced history. The brilliantly blue, supposedly cursed Hope Diamond, for example, has not brought much luck to its owners since it was discovered over 350 years ago. It was in the possession of Marie Antoinette and Louis XVI until their untimely deaths during the French Revolution. Subsequent owners also met with unfortunate outcomes until it was donated to the Smithsonian National Museum of Natural History where it is now safely on display. Another famous diamond, the 750 year-old Koh-i-Noor, has been owned by many royal rulers. It once decorated the Peacock Throne that was used by the Mughal Emperors of India, including Shah Juhan, the builder of the Taj Mahal. Now in England, the stone is part of the Imperial Crown. Due to an alleged curse, it can only ever be worn by the royal family’s female members. Finally, there is the Regent Diamond, which was unearthed in the early 1700’s. After being owned by several rulers, it disappeared during the French Revolution. Years later, it reappeared in the sword of Napoleon. But he was unable to hold onto it for long. After being defeated by the British in the Battle of Waterloo, the once-great ruler was exiled to the tiny island of Elba in disgrace. Since 1987, the Regent’s home has been at the French Royal Treasury in the Louvre in Paris. But you don’t need to travel to France or Great Britain or Washington D.C. to see the Regent Diamond, the Koh-i-Noor, and the Hope Diamond. Replicas of these three stones plus many more world-famous diamond replicas are on display at the Hillman Hall of Minerals and Gems. While you’re there, you can also admire some expertly crafted pieces of authentic diamond jewelry that would make any gem lover’s heart skip a beat.

Even though Hillman’s diamond collection is truly amazing, I can’t help but wonder if it would have impressed someone like Marilyn Monroe. Apart from a single piece of jewelry, the diamond wedding band that was given to her by Joe DiMaggio, she had no real affinity for diamonds. Apparently, the legendary actress didn’t believe that they’re a girl’s best friend. But if she had been given the opportunity to find out about all of the other meaningful ways in which diamonds benefit our world, perhaps this screen siren might have developed a new appreciation for these precious gems. I know that I have. I’d like to think that Marilyn would have too.

Shelby Wyzykowski is a Gallery Experience Presenter in CMNH’s Life Long Learning Department. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

[lupinepublishers]

lupine publishers|                Prediction of Brinell Hardness Number; A TIG Process Parameter Needed to Eliminate Post Weld Crack Formation and Stabilize Heat Input in Mild Steel Weldment Using Fuzzy Logic (FL)Research Article

The Brinell hardness number (BHN) is the load divided by the surface area of indentation. The diameter of the impression is measured with a microscope with a superimposed scale. BHN remains vital parameters for the assessment of weld quality and also to eliminate post weld crack formation. The focus of this study is to predict tig process parameter such as Brinell hardness number (BHN)  for  eliminating  post  weld  crack  formation,  and  stabilizing  heat  input  in  mild  steel  weldment.  The  key  input  parameters  considered  in  this  work  are  welding  current,  welding  voltage  and  welding  speed  while  the  response  or  measured  parameter  is  Brinell  hardness  number  (BHN).  Using  the  range  and  levels  of  the  independent  variables,  statistical  design  of  experiment  (DOE)  using central composite design (CCD) method was done. Hundred (100) pieces of mild steel coupons measuring 60 x 40 x10 were used  for  the  experiments.  The  experiment  was  performed  20  times,  using  5  specimens  for  each  run.  The  plate  samples  were  60  mm long with a wall thickness of 10mm. The samples were cut longitudinally with a Single-V joint preparation. The tungsten inert gas welding equipment was used to weld the plates after the edges have been bevelled and machined. The welding process uses a  shielding  gas  to  protect  the  weld  specimen  from  atmospheric  interaction.  For  this  study,  100%  pure  Argon  gas  was  used.  The  weld samples were made from 10mm thickness of mild steel plate; the plate was cut to size with the power hacksaw. The edges grinded and surfaces polished with emery paper and the joints welded and thereafter, the response (Brinell hardness number) was measured, recorded, and analysed using fuzzy logic.

153Copyright © All rights are reserved by Obahiagbon K.Journal of Mining and Mechanical EngineeringResearch ArticlePrediction of Brinell Hardness Number; A TIG Process Parameter Needed to Eliminate Post Weld Crack Formation and Stabilize Heat Input in Mild Steel Weldment Using Fuzzy Logic (FL)Pondi P1, Achebo J2 and Obahiagbon K3*1Department of Production Engineering, University of Benin, Nigeria2Department of Production Engineering, University of Benin, Nigeria3Department of Chemical Engineering, University of Benin, Nigeria*Corresponding author:Obahiagbon K, Department of Chemical Engineering, Faculty of Engineering, University of Benin, P.M.B 1154, Benin City, Edo State, NigeriaReceived:March 26, 2021 Published:April 22, 2021Introduction Most  of  the  structural  failures  happening  today  is  because  of  poor  weld  strength  Palani  et.al.  [1]  These  welding  failures  are  mostly influenced by improper combination of the welding process factors  Marseguerra  et  al.  [2]  The  quality  and  strength  of  a  weld  is  characterized  by  the  reduction  and  elimination  of  weld  defects  such  as  cracks,  undercut,  deformation,  porosity  [3]  in  addition  to  controlling the heat input which is a very strong determining factor needed  to  produce  a  reliable  weld  Shubhavardhan  et.  al.  [4]  One  of  the  fundamental  issues  facing  Engineers  in  the  manufacturing  sector  is  the  problem  of  choosing  the  most  suitable  combinations  of input process parameters to achieve the required optimum weld bead  quality  Springer  et.al.  [5]  It  is  a  well-known  fact  that  most  welders  mainly  focused  on  [6]  bead  geometry  and  aesthetics  of  the  weld  structure,  but  the  reduction  in  post  weld  cracks  which  determines  the  overall  quality  of  weldment  has  not  been  paid  much attention Navid et.al.[7] These problems can be solved with

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[aparnasonali-blog]

Global Inlaying Machine Market Growth 2019-2024

Acquire Market Research has announced market research Report On – “Global Inlaying Machine Market Growth 2019-2024″ with key players.

Inlaying Machine, or a mounting press machine, is a device used to encapsulate samples for metallographic preparation. Metallographic specimens are typically "mounted" using a hot compression thermosetting resin. In the past, phenolic thermosetting resins have been used, but modern epoxy is becoming more popular because reduced shrinkage during curing results in a better mount with superior edge retention. A typical mounting cycle will compress the specimen and mounting media to 4,000 psi (28 MPa) and heat to a temperature of 350 °F (177 °C). When specimens are very sensitive to temperature, "cold mounts" may be made with a two-part epoxy resin. Mounting a specimen provides a safe, standardized, and ergonomic way by which to hold a sample during the grinding and polishing operations.

Request Sample @ https://www.acquiremarketresearch.com/sample-request/413 First, for industry structure analysis, the Inlaying Machine industry is fragmented. A variety of manufacturers ranging from large multinational corporations to small privately owned companies compete in this industry. The top ten producers account for about 80% of the revenue market. Regionally, United States is the biggest production area of Inlaying Machine, also the leader in the whole Inlaying Machine industry. Second, the United States production increases from 4334 Units in 2011 to 4709 Units in 2015 with the average growth rate of more than 2.09%. Third, United States occupied 31.85% of the production market in 2015. It is followed by China and Europe, which respectively have around 30.72% and 26.91% of the global total industry. Other countries have a small amount of production. Geographically, Europe is the largest consumption market in the world, which took about 39.35% of the global consumption volume in 2015. United States shares 32.66% of global total. According to this study, over the next five years the Inlaying Machine market will register a xx% CAGR in terms of revenue, the global market size will reach US$ xx million by 2024, from US$ xx million in 2019. In particular, this report presents the global market share (sales and revenue) of key companies in Inlaying Machine business. This report presents a comprehensive overview, market shares, and growth opportunities of Inlaying Machine market by product type, application, key manufacturers and key regions and countries. This study considers the Inlaying Machine value and volume generated from the sales of the following segments: Segmentation by product type

Hot-pressing Inlaying

Cold-pressing Inlaying

Segmentation by application

Electronics Automotive & Aerospace Biomedical & Medical Others

More Info and TOC @ https://www.acquiremarketresearch.com/industry-reports/global-inlaying-machine-market-growth-2019-2024/413/

This report also splits the market by region

Americas ( United States ,Canada, Mexico, Brazil)

APAC    ( China, Japan, Korea ,Southeast Asia ,India ,Australia)

Europe   ( Germany ,France, UK  ,Italy ,Russia Spain)

Middle East & Africa (Egypt, South Africa,  Israel ,Turkey ,GCC Countries)

The report also presents the market competition landscape and a corresponding detailed analysis of the major vendor/manufacturers in the market.

The key manufacturers covered in this report    Struers    Buehler    LECO    Presi    Allied High Tech    Laizhou Weiyi    ATM GmbH    Plusover    BROT LAB    Shanghai Minxin    WHW In addition, this report discusses the key drivers influencing market growth, opportunities, the challenges and the risks faced by key manufacturers and the market as a whole. It also analyzes key emerging trends and their impact on present and future development. Research objectives    To study and analyze the global Inlaying Machine consumption (value & volume) by key regions/countries, product type and application, history data from 2014 to 2018, and forecast to 2024.    To understand the structure of Inlaying Machine market by identifying its various subsegments.    Focuses on the key global Inlaying Machine manufacturers, to define, describe and analyze the sales volume, value, market share, market competition landscape, SWOT analysis and development plans in next few years.    To analyze the Inlaying Machine with respect to individual growth trends, future prospects, and their contribution to the total market.    To share detailed information about the key factors influencing the growth of the market (growth potential, opportunities, drivers, industry-specific challenges and risks).    To project the consumption of Inlaying Machine submarkets, with respect to key regions (along with their respective key countries).    To analyze competitive developments such as expansions, agreements, new product launches, and acquisitions in the market.    To strategically profile the key players and comprehensively analyze their growth strategies.

Table of Contents:

1 Scope of the Report    1.1 Market Introduction    1.2 Research Objectives    1.3 Years Considered    1.4 Market Research Methodology    1.5 Economic Indicators    1.6 Currency Considered 2 Executive Summary    2.1 World Market Overview        2.1.1 Global Inlaying Machine Consumption 2014-2024        2.1.2 Inlaying Machine Consumption CAGR by Region    2.2 Inlaying Machine Segment by Type        2.2.1 Hot-pressing Inlaying        2.2.2 Cold-pressing Inlaying    

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[siva3155]

300 TOP MOST Machine Design - Mechanical Engineering Multiple choice Questions and Answers

Machine Design Multiple choice Questions with Answers :-

1. The ultimate strength of steel in tension in comparison to shear is in the ratio of (a) 1 : l (b) 2:1 (c) 3 : 2 (d) 2 : 3 (e) 1 : 2 Ans: c 2. The permissible stress for carbon steel under static loading is generally taken as (a) 2000-3000 kg/pm2 (b) 3000-4000 kg/cm2 (c) 4000-4500 kg/cm2 (d) 7500-10,000 kg/cm2 (e) 10,000-15,000 kg/cm2. Ans: c 3. The property of a material which enables it to resist fracture due to high impact loads is known as (a) elasticity (b) endurance (c) strength (d) toughness (e) resilience. Ans: d 4. A hot short metal is (a) brittle when cold (b) brittle when hot (c) brittle under all conditions (d) ductile at high temperature (e) hard when hot. Ans: b 5. Guest's theory of failure is applicable for following type of materials (a) brittle (b) ductile (c) elastic (d) plastic (e) tough. Ans: b 6. Rankine's theory of failure is applicable for following type of materials (a) brittle (b) ductile (c) elastic (d) plastic (e) tough. Ans: a 7. If an unsupported uniform cross sectional elastic bar is subjected to a longitudinal impact from a rigid bob moving with velocity v, then a compressive wave of intensity sc is propagated through the bar as follows (a) vpE (b) vVvF (c) WpE/2 (d) IvHpE (e) none of the above, where E = modulus of elasticity and p = mass density. Ans: a 8. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test (a) Brinell (b) Rockwell (c) Vicker (d) Shore's sceleroscope (e) none of the above. Ans: a 9. Resilience of a material is important, when it is subjected to (a) combined loading (b) fatigue (c) thermal stresses (d) wear and tear (e) shock loading. Ans: e 10. In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by (a) decreasing the cross-section area of' bar (b) increasing the cross-section area of bar (c) remain unaffected with cross-section area (d) would depend upon other factors (e) none of the above. Ans: a 11. .Other method of reducing shock load in the above case can be (a) to decrease length (b) to increase length (c) unaffected by length (d) other factors would decide same (e) none of the above. Ans: b 12. If a load W is applied instantaneously on a bar; then the stress induced in bar will (a) be independent of ratio of mass of load W to mass of bar (y) (b) increase with increase in y (c) decrease with decrease in y (d) depend on other considerations (e) none of the above. Ans: a 13. Brittle coating technique is used for (a) determining brittleness (b) protecting metal against corrosion (c) protecting metal against wear and tear (d) experimental stress analysis (e) non-destructive testing of metals. Ans: d 14. Stress concentration is caused due to (a) variation in properties of material from point to point in a member (b) pitting at'points or areas at which loads on a member are applied (c) abrupt change of section (d) all of the above (e) none of the above. Ans: d 15. The endurance limit of a material with finished surface in comparison to rough surface is (a) more (b) less (c) same (d) more or less depending on quantum of load (e) unpredictable. Ans: a 16. Plastic flow in ductile materials (a) increases the seriousness of static load-ing stress concentration (b) lessens the seriousness of static load¬ing stress concentration (c) has no effect on it (d) depends on other considerations (e) none of the above. Ans: b 17. The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be (a) same in both cases (b) 2 times more (c) 3 times more (d) 4 times more (e) unpredictable. Ans: c 18. The fatigue life of a part can be improved by (a) electroplating (b) polishing (c) coating (d) shot peening (e) heat treating. Ans: d 19. Stress concentration in static loading is more serious in (a) ductile materials (b) brittle materials (c) equally serious in both cases (d) depends on other factors (e) unpredictable. Ans: b 20. Stress concentration in cyclic loading is more serious in (a) ductile materials (b) brittle materials (c) equally serious in both cases (d) depends on other factors (e) unpredictable. Ans: a 21. Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to (a) dynamic loading (b) static loading (c) combined static and dynamic loading (d) completely reversed loading (e) all of the above. Ans: d 22. Pick up wrong statement. Fatigue strength can be increased by (a) cold working (b) shot peening (c) grinding and lapping surface (d) hot working (e) using gradual changes of section. Ans: d 23. Which of the following is not correct procedure to increase the fatigue limit (a) cold working (b) shot peening (c) surface decarburisation (d) under-stressing (e) all of the above. Ans: c 24. Coaxing is the procedure of increasing (a) metal strength by cycling (b) metal hardness by surface treatment (c) metal resistance to corrosion by coating (d) fatigue limit by overstressing the metal by successively increasing loadings (e) none of the above. Ans: d 25. Which is correct statement ? Stress concentration in static loading is (a) very serious in brittle materials and less serious in ductile materials (b) very serious in ductile materials and less serious in brittle materials (c) equally serious in both types of materials (d) seriousness would depend on other factors (e) none of the above. Ans: a 26. The notch angle of the Izod impact test specimen is (a) 10° (b) 20° (c) 30° (d) 45° (e) 60°. Ans: d 27. In Vicker's hardness testing, the pyramid indentor apex is (a) 40° (b) 122° (c) 136° (d) 152° (e) 161°. Ans: c 28. Which is correct statement ? Stress concentration in cyclic loading is (a) very serious in brittle materials and less serious in ductile materials (b) very serious in ductile materials and less serious in brittle materials (c) equally serious in both types of materials (d) seriousness would depend on other factors (e) none of the above. Ans: c 29. In testing a material for endurance strength, it is subjected to (a) static load (b) dynamic load (c) impact load (d) static as well as dynamic load (e) completely reversed load. Ans: e 30. If a material fails below its yield point, failure would be due to (a) straining (b) fatigue (c) creep (d) sudden loading (e) impact loading. Ans: b 31. The fatigue limit of a material (a) is greatly decreased by poor surface conditions (b) remains same irrespective of surface conditions (c) depends mainly on core composition (d) is dependent upon yield strength of material (e) none of the above. Ans: a 32. Cold working (a) increases the fatigue strength (b) decreases the fatigue strength (c) has no influence on fatigue strength (d) alone has no influence on fatigue strength (e) none of the above. Ans: a 33. Yield point in fatigue loading as compared to static loading is (a) same (b) higher (c) lower (d) depends on other factors (e) none of the above. Ans: c 34. Residual stress in materials (a) acts when external load is applied (b) becomes zero when external load is removed (c) is independent of external loads (d) is always harmful (e) is always beneficial. Ans: c 35. The building up of worn and uridersized parts, subjected to repeated loads by electroplating is (a) best method (b) extremely hazardous (c) has no effect as regards fatigue strength (d) cheapest method (e) all of the above. Ans: a 36. In nitrated parts, the origins of the fatigue cracks will occur at (a) surface (b) just below the surface (c) within the core (d) could occur anywhere (e) none of the above. Ans: e 37. Which process will increase the fatigue duration of parts ? (a) finishing and polishing (b) shot-peening (c) decarburisation (d) electroplating (e) all of the above". Ans: b 38. Which is correct statement ? (a) a member made of steel will generally be more rigid than a member of equal load-carrying ability made of cast iron (b) a member made of cast iron will generally be. more rigid than a member of equal load carrying ability made of steel (c) both will be equally rigid (d) which one is rigid will depend on several other factors (e) none of the above. Ans: b 39. Resistance to fatigue of a material is measured by (a) Young's modulus (b) coefficient of elasticity (c) elastic limit (d) ultimate tensile strength (e) endurance limit. Ans: e 40. In most machine members, the damping capacity of the material should be (a) low (b) zero (c) high (d) could be anything (e) none of the above. Ans: c 41. The ratio of endurance limit in shear to the endurance limit in flexure is (a) 0.33 (b) 0.4 (c) 0.5 (d) 0.55 (e) 0.6 Ans: d 42. For steel, the ultimate strength in shear as compared to ultimate strength in tension is (a) same (b) 1/2 (c) 1/3 (d) 1/4 (e) 2/3 Ans: e 43. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of (a) 0.25 (b) 0.45 (r) 0.55 (d) 0.65 (e)0.75. Ans: e 44. At low temperatures (say 75°C) the notched-bar impact value of steel (a) increases markedly (b) decreases markedly (c) remains same (d) depends on heat treatment carried out (e) none of the above. Ans: b 45. A bolt (a) has a head on one end and a nut fitted to the other (b) has head at one end and other end fits into a tapped hole in the other part to be joined (c) has both the ends threaded (d) is provided with pointed threads (e) requires no nut. Ans: a 46. The crest diameter of a screw thread is same as (a) major diameter (b) minor diameter (c) pitch diameter (d) core diameter (e) none of the above. Ans: a 47. If d is the diameter of bolt hole then for a flanged pipe joint to be leak proof, the circumferential pitch of the bolts should be (a) lOVZ (b) 10VZtol5Vd (c) 15Vdto20VZ (d) 20Vdto30Vd (e) 30V5"to40Vd. Ans: d 48. Maximum principal stress theory is applicable for (a) ductile materials (b) brittle materials (c) elastic materials (d) all of the above (e) none of the above. Ans: b 49. The following type of nut is used with alien bolt (a) alien nut (b) hexagonal nut (c) slotted nut (d) castle nut (e) any one of the above. Ans: e 50. A stud (a) has a head on one end and a nut fitted to the other (b) has head at one end and other end fits into a tapped hole in the other part to be joined (c) has both the ends threaded (d) has pointed threads (e) requires locking nuts. Ans: c 51. Shear stress theory is applicable for (a) ductile fnaterials (b) brittle materials (c) elastic materials (d) all of the above (e) none of the above. Ans: a 52. A tap bolt (a) has a head on one end and a nut fitted to the other (b) has head at one end and other end fits into a tapped hole in the other part o be joined (c) has both the ends threaded (d) has pointed threads (e) requires locking devices. Ans: b 53. For applications involving high stresses in one direction only the following type of thread would be best suited (a) ISO metric thread (b) acme thread (c) square thread (d) buttress thread (e) British Association thread. Ans: d 54. The included angle in unified of American National threads is (a) 60° (b) 55° (c) 47° (d) 29° (e) none of the above. Ans: a 55. The function of a washer is to (a) provide cushioning effect (b) provide bearing area (c) absorb shocks and vibrations (d) provide smooth surface in place of rough surface (e) act as a locking device. Ans: b 56. Cap screws are (a) similar to'small size tap bolts except that a greater variety of shapes of heads are available (b) slotted for a screw driver and generally used with a nut (c) used to prevent relative motion be-tween parts (d) provided with detachable caps (e) similar to stud. Ans: a 57. An alien bolt is (a) self locking bolt (b) same as stud (c) provided with hexagonal depression in head (d) used in high speed components (e) provided with countersunk head. Ans: c 58. The deflection of a cantilever beam under load W is 8. If its width is halved, then the deflection under load W will be (a) 28 (b) 8/2 (c) 48 (d) 8/4 (e) none of the above. Ans: c 59. Ball bearing type screws are found in following application (a) screw jack (b) aeroplane engines (c) crane (d) steering mechanism (e) bench vice. Ans: d 60. Set screws are (a) similar to small size tap bolts except that a greater variety of shapes of heads are available (b) slotted for a screw driver and generally used with a nut (c) used to prevent relative motion be-tween parts (d) similar to stud (e) none of the above. Ans: c 61. A self locking screw has (a) fine threads (b) coarse threads (c) coefficient of friction > tangent of load angle (d) hole for inserting split pin (e) two nuts for locking. Ans: c 62. The designation M 33 x 2 of a bolt means (a) metric threads of 33 nos in 2 cm. (b) metric threads with cross-section of 33 mm (c) metric threads of 33 mm outside diameter and 2 mm pitch (d) bolt of 33 mm nominal diameter having 2 threads per cm (e) none of the above. Ans: c 63. Machine screws are (a) similar to small size tap bolts except that a greater variety of shapes of heads are available (b) slotted for a screw driver and generally used with a nut (c) used to prevent relative motion be-tween two parts (d) similar to stud (e) none of the above. Ans: b 64. Rivets are generally specified by (a) thickness of plates to be riveted (b) length of rivet (c) diameter of head (d) nominal diameter (e) all of the above. Ans: d 65. The edges of a boiler plate are bevelled to an angle of (a) 30° (b) 45° (c) 60° (d) 80° (e) 85°. Ans: d 66. Which of the following is a permanent fastening ? (a) bolts (b) keys (c) cotters (d) rivets (e) screws. Ans: d 67. In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia. of rivet d should be equal to (a) d (b) 1.25 d (c) 1.5 d (d) 1.75 d (e) 2 d. Ans: c 68. If the tearing efficiency of a riveted joint is 75%, then the ratio of diameter of rivet to the pitch is equal to (a) 0.2 (b) 0.25 (c) 0.50 (d) 0.6 (e) 0.75. Ans: b 69. Transverse fillet welded joints are designed for (a) tensile strength (b) compressive strength (c) shear strength (d) bending strength (e) torsional strength. Ans: a 70. Jam nut is a locking device in which (a) one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming (b) a slot is cut partly in middle of nut and then slot reduced by tightening a screw (c) a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip (d) through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end (e) none of the above. Ans: a Machine Design Interview Questions and Answers :- 71. The pitch of threads on a Jock nut in comparison to pitch of nut is (a) same (b) coarser (c) finer (d) very coarse (e) very fine. Ans: a 72.Buttress threads are usually found on (a) screw cutting lathes (b) feed mechanisms (c) spindles of bench vices (d) screw jack (e) railway carriage couplings. Ans: e 73. In order to obtain bolt of uniform strength (a) increase shank diameter (b) increase its length (c) drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread (d) tighten die bolt properly (e) all of the above. Ans: c 74. A key capable of tilting in a recess milled out in a shaft is known as (a) wood-ruff key (b) feather key (c) flat saddle key (d) gib head key (e) hollow saddle key. Ans: a 75. A key made from a cylindrical disc having segmental cross-section, is known as (a) wood-ruff key (b) feather key (c) flat saddle key (d) gib head key (e) hollow saddle key. Ans: a 76. A tapered key which fits in a keyway in the hub and is flat on the shaft, is known as (a) wood-ruff key (b) feather key (c) flat saddle key (d) gib head key (e) hollow saddle key. Ans: c 77. Fibrous fracture occurs in (a) ductile material (b) brittle material (c) elastic material (d) hard material (e) all of the above. Ans: a 78. Turn buckle has (a) right hand threads on bout ends (b) left hand threads on both ends (c) left hand threads on one end and right hand threads on other end (d) no threads (e) threads in middle portion. Ans: c 79. Eye bolts are used for (a) foundation purposes (b) locking devices * (c) absorbing shock and vibrations (d) transmission of power (e) lifting and transportation of machines and cubicles. Ans: e 80. Elastic nut is a locking device in which (a) one small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming (b) a slot is cut partly in middle of nut and then slot reduced by tightening a screw (c) hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip (d) through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end (e) none of the above, Ans: c 81. If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation (a) 102 d (b) 124 d (c) 138 d (d) 151 d (e) 168 d. Ans: e 82. If threads on a bolt are left hand, threads on nut will be (a) right hand with same pitch (b) left hand with same pitch (c) could be left or right hand (d) right hand with fine pitch (e) left hand with fine pitch. Ans: b 83. Taper usually provided on cotter is (a) 1 in 5 (b) 1 in 10 (c) 1 in 24 (d) 1 in 40 (e) 1 in 50. Ans: c 84. Applications in which stresses are encountered in one direction only uses following type of threads (a) metric (b) buttress (c) acme (d) square (e) BSW. Ans: b 85. The draw of cotter need not exceed (a) 3 mm (b) 5 mm (c) 10 mm (d) 20 mm (e) 25 mm. Ans: a 86. A bench vice has following type of threads (a) metric (b) square (c) buttress (d) acme (e) BSW. Ans: d 87. The valve rod in a steam engine is connected to an eccentric rod by (a) cotter joint (b) bolted joint (c) kunckle joint (d) universal coupling (e) gib and cotter joint. Ans: c 88. Split nut is a locking device in which (a) one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming (b) a slot is cut partly in middle of nut and then slot reduced by tightening screw (c) a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip (d) through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at the other end (e) none of the above. Ans: b 89. Taper on the cotter and slot is provided (a) on both the sides (b) on one side only (c) on none of the sides (d) may be provided anywhere (e) none of the above. Ans: b 90. The function of cutting oil when threading a pipe is to (a) provide cooling action (b) lubricate the dies (c) help remove chips (d) all of the above (e) none of the above. Ans: d 91. Silver-based solder is used for (a) flaring (b) brazing (c) soft soldering (d) fusion welding (e) none of the above.' Ans: b 92. For tight leakage joints, following type of thread is best suited (a) metric (b) buttress (c) square (d) acme (e) NPT (national pipe threads). Ans: e 93. In order to permit the thermal expansion/contraction of tubing, it should be (a) crimped (b) honed (c) flared (d) bent (e) none of the above. Ans: d 94. A tube has the following advantage over pipe (a) lighter and easier to handle (b) greater shock absorption (c) smoother inside walls (d) all of the above (e) none of the above. Ans: d 95. The strap end of a connecting rod of steam engine is joined by (a) gib of cotter joint (b) sleeve and cotter joint (c) spigot socket cotter joint (d) knuckle joint (e) universal coupling. Ans: a 96. A backing ring is used inside the pipe joint when making a (a) butt weld (b) fillet weld (c) sleeve weld (d) socket weld (e) tube weld. Ans: a 97. The shear plane in case of bolts should (a) be across threaded portion of shank (b) be parallel to axis of bolt (c) be normal to threaded portion of shank (d) never be across the threaded portion (e) none of the above. Ans: d 97. Castle nut is a locking device in which (a) one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming (b) a slot is cut partly is middle of nut and then slot reduced by tightening a screw (c) a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip (d) through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter pin spitted and bent in reverse direction at other end (e) none of the above. Ans: d 98. When a nut is tightened by plaping a washer below it, the bolt will be subjected to following type of loads (a) compression (b) tension (c) shear (d) combined loads (e) all of the above. Ans: b 99. Gear box is used (a) to produce torque (b) for speed reduction (c) to obtain variable speeds (d) to increase efficiency of system (e) to damp out vibrations. Ans: c 100. The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for (a) reducing stress concentration (b) ease of manufacture (c) safety (d) fullering and caulking (e) all of the above. Ans: d 101. The piston rod of a steam engine is usually connected to the crosshead by means of (a) bolted joint (b) kunckle joint (c) cotter joint (d) universal joint (e) universal coupling. Ans: c 102. Which of the following pipe joints would be suitable for pipes carrying steam (a) flanged (b) threaded (c) bell and spigot (d) expansion (e) compression. Ans: d 103. Spring index is (a) ratio of coil diameter to wire diameter (b) load required to produce unit deflection (c) its capability of storing energy (d) indication of quality of spring (e) nothing. Ans: a 104. The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is (a) larger (b) smaller (c) equal (d) larger/smaller depending on diameter of spring coil (e) unpredictable. Ans: a 105. Form coefficient of spring is (a) ratio of coil diameter to wire diameter (b) load required to produce unit deflection (c) its capability of storing energy (d) concerned With strength of wire of spring (e) nothing Ans: c 106. Spring stiffness is (a) ratio of coil diameter to wire diameter (b) load required to produce unit deflection (c) its capability of storing energy (d) its ability to absorb shocks (e) none of the above. Ans: b 107. When two springs are in series (having stiffness K), the equivalent stiffness will be (a) K (b) K/2 (c) 2K (d) KIA (e) UK. Ans: b 108. When a close coiled helical spring is compressed, its wire is subjected to (a) tension (b) shear (c) compression (d) all of the above (e) none of the above. Ans: a 109. If a spring is cut down into two springs, the stiffness of cut springs will be (a) half (b) same (c) double (d) unpredictable (e) none of the above. Ans: c 110. Belt slip may occur due to (a) heavy load (b) loose belt (c) driving pulley too small (d) all of the above (e) none of the above. Ans: d 111. Aircraft body is usually fabricated by (a) welding (b) precasting (c) rivetting (d) casting (e) unconventional methods. Ans: c 112. If two springs are in parallel then their overall stiffness will be (a) half (b) same (c) double (d) unpredictable (e) none of the above. Ans: c 113. In hydrodynamic bearings (a) the oil film pressure is generated only by the rotation of the journal (b) the oil film is maintained by supplying oil under pressure (c) do not require external supply of lubricant (d) grease is used for lubrication (e) none of the above. Ans: a 114. Antifriction bearings are (a) sleeve bearings (b) hydrodynamic bearings (c) thin lubricated bearings (d) ball and roller bearings (e) none of the above. Ans: e 115. If p = bearing pressure on projected bearing area, z = absolute viscosity of lubricant, and N = speed of journal, then the bearing characteristic number is given by (a) ZN/p (b) p/ZN (c) Z/pN (d) N/Zp (e) Zp/N. Ans: a 116. The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is (a) 0.01 micron (b) 0.1 micron (c) 1 micron (d) 10 microns (e) 25 microns. Ans: c 117. In hydrostatic bearings (a) the Oil film pressure is generated only by the rotation of the journal (b) the oil film is maintained by supplying oil under pressure (c) do not require external supply of lubricant (d) grease is used for lubrication (e) none of the above. Ans: b 118. Oil in journal bearing should be applied at the point where load is (a) nil or lightest (b) maximum (c) average (d) any one of the above (e) unpredictable. Ans: a 119. The rated life of a bearing varies (a) directly as load (b) inversely as square of load (c) inversely as cube of load (d) inversely as fourth power of load (e) none of the above. Ans: c 120. In oilness bearings (a) the oil film pressure is generated only by the rotation of the journal (b) the oil film is maintained by supplying oil under pressure (c) do not require external supply of lubricant (d) grease required to be applied after some intervals (e) none of the above. Ans: c 121. In V-belt drive, belt touches (a) at bottom (b) at sides only (c) both at bottom and sides (d) could touch anywhere (e) none of the above. Ans: b 122. Three different weights fall from a certain height under vacuum. They will take (a) same time to reach earth (b) times proportional to weight to reach earth (c) times inversely proportional to weight to reach earth (d) unpredictable (e) none of the above. Ans: a 123. In cross or regular lay ropes (a) direction of twist of wires in strands is opposite to the direction of twist of strands (b) direction of twist of wires and strands are same (c) wires in two adjacent strands are twisted in opposite direction (d) wires are not twisted (e) none of the above. Ans: a 124. In standard taper roller bearings, the angle of taper of outer raceway is (a) 5° (b) 8° (c) 15° (d) 25° (e) 40°. Ans: d 125. In composite or reverse laid ropes (a) direction of twist of wires in strands is opposite to the direction of twist of strands (b) direction of twist of wires and strands are same (c) wires in two adjacent strands are twisted in opposite direction (d) wires are not twisted (e) none of the above. Ans: c 126. Whether any core is required in wire ropes (a) yes (b) no (c) sometimes (d) rarely (e) very often. Ans: a 127. If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to (a) diameter of bolt (b) 0.75 x diameter of bolt (c) 1.25 x diameter of bolt (d) 1.5 x diameter of bolt (e) 0.5 x diameter of bolt. Ans: a 128. Basic shaft is one (a) whose upper deviation is zero (b) whose lower deviation is zero (c) whose lower as well as upper deviations are zero (d) does not exist (e) none of the above. Ans: a 129. Basic hole is one (a) whose upper deviation is zero (b) whose lower deviation is zero (c) whose lower as well as upper deviations are zero (d) does not exist (e) none of the above. Ans: b 130. I.S. specifies following total number of grades of tolerances (a) 18 (b) 16 (c) 20 (d) 22 (e) 14. Ans: a 131. For standard coarse threads of nut, the threads will be as strong in failure by shear as the bolt in tension, if the height of nut (h) is approximately (a) 0.4 times (b) 0.6 times (c) 0.7 times (d) 0.8 times (e) 0.9 times the normal diameter of bolt. Ans: a 132. Allen bolts are (a) self locking bolts (b) designed for shock load (c) used in aircraft application (d) provided with hexagonal depression in head (e) uniform strength bolts. Ans: d 133. The resultant axial load on a bolt depends on (a) initial tension (b) external load applied (c) relative elastic yielding (springness) of the bolt and the connected member (d) (a) and (b) above (e) (a), (b) and (c) above. Ans: e 134. The connecting rod bolts are tightened up so that tightening stress (a) is just sufficient to hold parts together (b) approaches yield point (c) is 50% of yield point (d) is about yield point divided by safety factor (e) none of the above. Ans: b 135. The connecting rod bolts are tightened up with initial tension greater than the external load so that (a) joint may not open up (b) bolts are weakest elements (c) the resultant load on the bolt would not be affected by the external cyclic load (d) bolts will not loosen during service (e) none of the above. Ans: c 136. If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited (a) square (b) acme (c) buttress (d) BSW (e) metric. Ans: c 137. When a bolt is subjected to shock loading, the resilience of the bolt should be considered in order to prevent breakage at (a) shank (b) head (c) in the middle (d) at the thread (e) anywhere in the bolt. Ans: d 138. The shock absorbing capacity of a bolt can be increased by (a) tightening it properly (b) increasing shank diameter (c) grinding the shank (d) using washer (e) making shank diameter equal to core diameter of thread. Ans: e Machine Design Interview Questions :- Read the full article

[millioninsights]

SAMPLE POLISHING MACHINE MARKET IS RISING DEMAND FROM AUTOMOTIVE, AEROSPACE AND DEFENSE SECTORS

Global sample polishing machine market is segmented into Automatic, Semi-automatic, Manual, and Dry & Wet, based on product. Based on application the sample polishing machine market is segmented into furniture/wood, hardware field, parts processing, material engineering, semiconductor failure analysis and precision optics.

The sample polishing machine is driven by a process which involves a soft material comprising abrasives in which the harder sample is rubbed. The process is mechanical starting with cutting the harder material. Next, by using a relatively small and cut particle of abrasives, the sample becomes more highly polished. The sample then remains stationary and the soft material containing the fine abrasives passages against it. Otherwise, soft abrasive material may be held tightly & rotated. Commercially, a large number of different machines are available for both grinding &polishing for microscopy and analysis.

For more information visit at : https://www.millioninsights.com/industry-reports/sample-polishing-machine-market

In grinding, the process removes saw marks and levels and cleans the specimen surface. Grinding uses fixed abrasives and the particles are bonded to paper and platen for instant removal of stock. For example, lapping is used in ceramography and ceramic manufacturing to generate extremely flat surfaces. Lapping is a technique for grinding or coarse polishing with an abrasive slurry contrary to a hard metal plates.

Ceramographic specimens can be polished manually, but automatic machines normally result into better-quality, fast and more reproducible outcome. Manual grinding allows enhanced controls of grinding depth than automatic grinding which is important when the cross section is certain. Diamond abrasives are suggested for grinding most ceramics but silicon carbide and cubic boron nitride can also be utilized.

To get free sample report Visit at : https://www.millioninsights.com/industry-reports/sample-polishing-machine-market/request-sample

Sample polishing is done after grinding, with a lubricant and progressively small diamond abrasives. Thus, polishing is best achieved when it goes through progressively smaller diamond grains with enhanced longer time. Overall, the sample polishing machine market is likely to grow at a higher CAGR during the forecast period.

[langfangmfr]

Analysis of Cause of Cracking of Stainless Steel Flange

1. Physical and chemical analysis

First, the chemical composition of cracked flange was analyzed.

The analysis results show that the chemical composition of the flange and welding material conform to the relevant standard requirements. Brinell hardness test is carried out on the outer surface and sealing surface of the flange respectively, and the Brinell hardness test meets the requirements of JB4728-2000 standard.

Under the premise of qualified material chemical composition, qualification of hardness testing, pipeline installation meet technical requirements and pressure test operation specification, pipe flange cracks in the process of pressure test, indicating that the defects are related to the internal structure of stainless steel flanges or other unknown factors.

2. Crack properties analysis

2.1 surface crack morphology

The leakage flanges were cut from the pipe to carry out a comprehensive macroscopic examination. It was found that there was a crack on the surface of the flange, the longest was 3mm, the width was 0.5mm, the crack and its vicinity had produced rust stains, and the surface of the flange bolt holes also found more cracks; the flange seal face and other positions found a number of non-metallic inclusions, individual nonmetallic inclusions. The metal inclusions formed small pits on the surface of the flange sealing surface, the maximum of the pits was 2.0mm, the smallest was 0.8mm, and the edges of the pits were tiny cracks visible to the naked eye.

The field macroscopic examination of the other austenitic stainless steel flanges of the same factory and the same batch found that many flanges have different degrees of defects, and some flanges have obvious cracks on the outer surface of the flanges. Macroscopic examination results further show that flange leakage is related to flange itself.

2.2 Crack morphology section

In order to further explore the true cause of flange leakage, a flanged flanged flange was randomly selected to form small pits with non-metallic inclusions on the cover of the same factory and on the same batch. The carbon steel flanges were dissected and divided into three parts of uneven size. A careful observation of its profile found that 4 of the 6 sections of the flange had naked eyes. Visible cracks and cracks almost run through the entire section.

One of the selected sections was observed after rough grinding, fine grinding and corrosion. The cracks were more obvious and almost penetrated the whole section. The crack has a certain width, and most of the cracks are filled with black non-metallic inclusions. One of the inclusions is about 3.0mm, the diameter of the flange is about 2.5mm, the upper cover of the inclusions to the dense cover has obvious patch welding marks, the repair welding area is about 380mm2, and the welding depth is up to 3.0mm.

In this new process pipeline, the composition of the pipe is not an old product, but a newly purchased product. In the flange section, a number of cracks containing non-metallic inclusions are found in the flange section. It can be preliminarily determined that the crack is related to a large number of non-metallic inclusions. The weld marks on the profile are a very puzzling and abnormal phenomenon.

2.3 metallographic analysis

In order to further explore the cause of the crack, it is clear whether the newly purchased flange has really experienced the repair welding before the group welding to the pipe, and the crack position of the flange section is examined by metallographic examination.

The specimens in 1 are finely grinded and polished on the position of repair welding marks on the flange section. Under 100 times the microscope, the cracks are clearer. The longer cracks contain a large strip of non-metallic inclusions (see Figure 2) and the scattered nonmetallic inclusions on the section; the crack tip is bald and blunt, and both sides of the crack are not seen. The abnormal metallographic structure of the austenitic stainless steel is a typical austenitic stainless steel structure. Determination of 3 crack properties

The crack morphology, fracture characteristics, crack micromorphology and metallographic analysis of the flanges show that the crack is a forged crack along the tip of the inclusion in the process of flange production. In order to eliminate the obvious cracks on the flange surface, the repair welding was done before flange.

3. crack cause analysis

3.1 the existence of non-metallic inclusions is the root cause of cracks.

Due to the large number of non-metallic inclusions in the forging blank of the flanges, during the forging process, the volume type inclusions are repeatedly forged and turned into an area type inclusion, resulting in a forged crack along the tip of the inclusions. The larger inclusions become larger cracks after forging, and smaller inclusions become smaller cracks after forging. Most of these cracks are buried cracks.

After the forging of the forging billet, some of the buried cracks become surface cracks. This is the reason that there are more cracks in the inner and outer surfaces of the flange and the holes in the bolt holes in the macroscopic inspection. In order to make the products out of the factory, the manufacturers have taken the means of grinding, eliminating surface cracks, repairing welding and re machining, so that there is no obvious defect in the appearance of the flange. This is the reason why the flange repair area is 380mm2 and the repair depth is 3mm.

3.2 the forging crack is further expanded under test pressure, resulting in the final leakage of flange.

A large number of non-metallic inclusions can reduce the plasticity and toughness of the material. The slag inside the crack causes the stress concentration of the crack tip, and the flange can not bear the external load. In the process of pressure resistance test, the test pressure has just reached 0.6MPa, and the flange will crack and leak. 5 measures taken

(1) replace all the flanges of all problems.

(2) continue to look for other fittings in the same plant and batch, and use corresponding inspection methods to confirm whether they are qualified.

(3) in addition to the chemical composition and mechanical properties of the newly changed flanges, the macroscopic inspection should be carried out to evaluate the geometrical size and surface smoothness of the alloy steel flanges, and to check whether there is an abnormal geometric discontinuity.

[hsmleindia]

Automatic Metallographic Specimen Grinding & Polishing Machine

Automatic Metallographic specimen grinding and polishing machine is equipped with an automatic polishing head and features step-less speed changing and three-level constant speed for grinding and polishing. The working time can be preset and the rotating direction can be controlled. It can finish the whole process of rough grinding, fine grinding, rough polishing, and finishing polishing for specimen preparation. It is the necessary metallographic specimen-preparing instrument for use in factories, scientific research institutes, and laboratories of colleges.It is a specialized piece of equipment used in material science and metallurgy laboratories to prepare metallographic specimens for microscopic examination. This machine automates the process of grinding and polishing metallographic samples, improving efficiency and consistency in sample preparation.

[basairmechanical-blog]

knowledge Foreign polishing machine performance characteristics and development!

Foreign polishing machine performance characteristics and development!

I. Abrapol-10 high-tech automated site type metallographic arc tile polishing machine developed by Denmark Struers.

 The specimens can be mounted on special fixtures without inserts, and the fixtures are driven by another motor, the direction of rotation of which is opposite to that of the polishing disk. The pressure between the fixture and the polishing plate can be arbitrarily adjusted between 0-7ON. When the predetermined polishing time is reached, the jig automatically lifts and stops.

 The fixture is characterized by the ability to adapt to various shapes of specimens. For wire rods and small-sized bar specimens, the specimens can be divided into three groups and fixed on the fixtures with thick steel plates and screws. Each group can hold 20 to 40 wire specimens, for each fixture of a larger specimen. Can hold 6 pieces.

 The sample hole in the fixture is designed to keep the sample always in contact with the fixture and the fixing screw at three points. If two people use three such devices, six to eight fixture specimens can be prepared in lh. In fact, the total effective time of each fixture specimen on three devices is only 6 minutes in total, with high polishing efficiency, and This kind of polishing quality can meet the requirements of metallographic analysis. Second, the United States Buehler company developed vanguard automatic arc tile polishing machine.

 This type of tile polishing machine is fully automatic from the rough polishing to the final polishing process. It can set up 50 common working procedures, with friendly operation interface, color LCD display, touch operation, and clamps between each process of the whole process. The cleaning and drying of the sample and the sample fully ensure the high efficiency and high system of sample preparation, the fully automated mode of the operation process, the saving of labor and the improvement of efficiency and quality.

 The specimen is moved by the polishing arm in a polishing plate according to a certain trajectory, and the pressure on the polishing arm can be adjusted as required, up to 20N. During a predetermined polishing time, this pressure will gradually decrease to zero automatically, which reduces polishing defects. The speed of the polishing arm can also be adjusted, each process only takes 2 ~ 5min, suitable for a variety of materials. These ceramic floor tiles making machine tiles production machines are meant to serve as a guide for business owners on how to both identify potential opportunities for transformative innovation and how to adapt to the constantly changing technologies of today. For more advice on tips, please visit our website Basair Mechanical. Do not hesitate to contact us if you are interested. While buying the products, make sure that you purchase them from a reputed and trusted seller - either online or offline. Foshan Basair Mechanical & Electrical Co., Ltd is specialised in the field of , offering a wide range of products like grinding wheel composition, tiles production machines, tiles production machines,etc. Media contact Company Name: Foshan Basair Mechanical & Electrical Co., Ltd Address: NO.7Keda North Road,A Area,Shishan Industry Zone,Nanhai Area,Foshan City,Guangdong,China E-mail: basairkjj@vip.126.com Website: http://www.fsbsr.com

[hallsara139]

The surface of a metallographic specimen is prepared by various methods of grinding, polishing, and etching. After preparation, it is often analyzed using optical or electron microscopy.

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100+ TOP MMT Lab Viva Questions and Answers

MMT Lab Viva Questions :-

TENSILE TEST: 1) Differentiate between Engineering Stress/Strain and True Stress/Strain. 2) What is meant by Plastic & Elastic Deformation? 3) Define Upper Yield Point; Lower Yield Point; Ultimate Strength; Fracture Strength. 4) What is meant by Gauge Length? 5) What are the various types of fractures? 6) Differentiate between Brittleness and ductility? 7) Define the term Malleability? 8) What is Strain hardening? 9) How the microstructural defect like slip effects the deformation? COMPRESSIVE STRENGTH TEST: 1) Differentiate between Compressive strength and tensile strength. 2) Describe the fracture mechanism of a material under compressive loading. 3) Theoretically compressive strength should be same as the tensile strength of a material, but practically it is not. Why? 4) What is anisotropy? How does it affect the mechanical properties? MODULUS OF RIGIDITY: 1) What is meant by modulus of rigidity? 2) Define torsion strength. 3) What are the factors which may affect the angle of twist? 4) What will be the effect on strength if a solid circular shaft is replaced by a hallow shaft of same dimension. 5) What is meant by strain energy? Give its expression in torsion for solid and hollow circular shaft. 6) What is Poisson’s Ratio? IMPACT TEST: 1) What is meant by toughness? 2) What is the purpose of V-notch in impact testing and what is its dimension? 3) What is resilience? 4) How does tempering change the toughness of a material? 5) Define Notch Impact Strength & Modulus of Rupture. 6) Differentiate between Izod & Charpy impact testing techniques? YOUNG’S MODULUS: 1) What is Young’s Modulus? 2) What is meant by Moment of Inertia? 3) How to find out the least count of vernier caliper. 4) What is the effect of temperature on Young’s Modulus? 5) How will you define a beam? 6) What is the difference between a simple supported beam & cantilever beam? 7) What are the formulae used to calculate the Moment of Inertia of a Square section beam; Rectangular section beam and a circular beam about the axis? 8) What is meant by Polar Moment of Inertia & how is it calculated? 9) Derive the relationship between Young’s Modulus, Modulus of Rigidity & Bulk Modulus. 10) Describe different types of loads on beam with the help of sketches. HEAT TREATMENT: 1) What is meant by heat treatment? 2) What are the different types of heat treatment? 3) Enumerate the need for heat treatment of steel? 4) List different types of hardness testing methods? 5) What is meant by BHN? 6) Differentiate between hardenability and hardness? 7) What are the different types of indenters used in hardness testing? 8) What are the factors which affect the hardness of steels? 9) Why is the minor load applied before applying the major load? 10) Derive the formula to calculate BHN. MICROSTRUCTURES: 1) Why the microstructures of metals are different from each other? 2) What are the effects of microstructure of steel and CI on their mechanical properties? 3) In which way the microstructure of copper is different from the microstructure of brass? 4) Define Pearlite, Austenite, Ferrite, Cementite, Martensite, Bainite, and Ledeburite. 5) What is the purpose of alloying? Describe few alloys of Copper and Aluminium. 6) How are steels classified based on their alloying (carbon) content? 7) What is Cast Iron? What are its types? 8) What are stainless steels? Give its composition. 9) Discuss in brief, the steel manufacturing process. 10) Discuss the properties and manufacturing process of the following: Composites; Ceramics; Plastics and Glass. 11) What are the specifications of grinding and polishing machines? 12) What is lapping? Which degree of accuracy can be achieved in metals by polishing? 13) Why is grinding performed before polishing? 14) What is the need of polishing on four grades of emery paper? 15) Why is the specimen rotated by 90°, while changing from one grade of emery paper to another? 16) Why is dry polishing done before wet polishing? 17) What is the purpose of wet polishing after dry polishing? 18) Why is alumina powder used in wet polishing? 19) What is the purpose of etching? 20) Which etchant is used for etching MS; aluminium; copper? 21) What is the principle of working of metallurgical microscope? MMT Lab Viva Questions and Answers Pdf :: Read the full article

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Andalusite Superfine Grinding Mill

Andalusite is a rock-forming mineral that is mined for use in high-temperature refractories. Gem-quality specimens are cut into faceted gems and cabochons.

Andalusite forms during the regional metamorphism of shale. It is found in schist and gneiss at some present and ancient convergent plate boundaries where the rocks have been exposed to the temperatures and pressures needed for its formation. In these rocks, andalusite is often associated with kyanite and sillimanite.

Andalusite also forms during the contact metamorphism of argillaceous rocks. In this situation, it can form within the metamorphosed rock or in veins and cavities within the igneous rock. It can be associated with cordierite in hornfels, granite, and granitic pegmatite.

The rare transparent variety of Andalusite is used as a minor gemstone. Chiastolite cross-sections are often cut and polished to bring out the distinctive cross-shaped pattern, and Chiastolite crystals may also be cut along their cross-section and used in jewelry as a Christian symbol.

Fengli andalusite superfine grinding machine has been widely used in making fine powder or micro powder, which is applicable to non-flammable and non-explosive materials with hardness less than 6, such as the calcite, chalk, limestone, dolomite, kaolin, bentonite, talcum, talc, diatomite, barite, gypsum, alum earth, graphite, fluorite, etc.

If you are interested in our Andalusite superfine grinding mill, please refer to: Tel: +86-597-2285225 Email: sales2@fengli-china.com

Website: http://www.fengli-china.com/

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Automatic Metallographic Specimen Grinding and Polishing Machine

Automatic Metallographic specimen grinding and polishing machine is equipped with an automatic polishing head and features step-less speed changing and three-level constant speed for grinding and polishing. The working time can be preset and the rotating direction can be controlled. It can finish the whole process of rough grinding, fine grinding, rough polishing and finishing polishing for specimen preparation. It is the necessary metallographic specimen-preparing instrument for use in factories, scientific research institutes, and laboratories of colleges.

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Automatic Metallographic Specimen Grinding & Polishing Machine-1000P

Automatic Metallographic Specimen Grinding & Polishing Machine-1000P equipped with automatic polishing head and features stepless speed changing and four-level constant speed for grinding and polishing. The working time can be preset and the rotating direction can be controlled. It can finish the whole process of rough grinding, fine grinding, rough polishing and finishing polishing for specimen preparing. It is the necessary metallographic specimen preparing instrument for using in factories, scientific research institutes and laboratories of colleges. This stage involves using grinding papers or abrasive wheels with varying grit sizes to remove surface imperfections and achieve a flat and uniform surface. After the grinding stage, the machine moves the samples to a polishing stage. This stage involves using polishing cloths or pads with fine abrasives and a polishing solution to create a smooth and reflective surface finish.

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Automatic Metallographic Specimen Mounting Press

Metallographic Specimen Mounting Press is used to inlay small specimens, specimens in irregular shapes, or specimens which are not easy to take up, it is the preceding process before grinding and polishing metallurgical or rock specimens. The inlaying operation serves to facilitate the grinding and polishing operations of the specimens and the routine observation of the composition of the material under the metallurgical microscope. The machine is equipped with built-in water cooling system and it is heated, and intensified with pressure automatically. After the formation of the specimen under pressure, it stops the operation and discharges the pressure also in an automatic way. With another press of the knob, the machine automatically turns up the specimen, which may be taken away. Note: It is only for the hot solid materials (such as urea-formaldehyde molding powder and Bakelite powder) with the temperature automatically regulated and controlled.