This set of Engineering Materials and Metallurgy Questions and Answers for Freshers focuses on “Miscellaneous Alloying Elements – 2”.
1. Which nickel alloy is used as a substitute in tableware and jewelry?
Explanation: Nickel-silver is used as a low-cost substitute for silver in jewelry and tableware, by electroplating on the surface. Surprisingly, however, it does not contain any silver. They are added to appear silvery-white and improve corrosion resistance and strength. They can also be used for musical and scientific instruments, and marine applications.
2. Which of the following is an application of Inconel?
a) Furnace chamber
b) Chemical storage tank
d) Spray nozzles
Explanation: Inconel is a nickel-chromium alloy containing 80% nickel, 14% chromium, and 6% iron. They are used in chemical industries due to its excellent corrosion resistance. The leftover choices are examples of various Hastelloys.
3. What is the melting point of Tin?
Explanation: Tin is a non-toxic white, soft metal which has a low melting point of 231.9oC and a high boiling point of 2270oC. It becomes highly fluid when molten. This helps it as a coating for other metals.
4. Which of the following is a tarnish resistant alloy?
a) Soft solder
Explanation: Pewter is an alloy of tin containing 7% antimony and 2% copper. It is used as a tarnish resistant. It is easy to cast and worked into various shapes.
5. Soft solder is a _______ tin alloy.
Explanation: Soft solder is a tin alloy containing 20-70% tin and remaining lead. This eutectic structure, with 63% tin, is used in electrical industry. Alloys with 50% tin are a general purpose solder. Lower tin content (15-20%) is used for dipping solders for automotive radiator cores.
6. What effect does cobalt have on steel?
a) Increases hardenability
b) Decreases hardenability
c) Changes color
d) No change
Explanation: Cobalt reduces the hardenability of steel. When it is dissolved in ferrite, cobalt provides resistance to softening at high temperatures.
7. What is the melting point of titanium?
Explanation: Titanium is an element which is abundantly available on earth. At 885oC it transforms from alpha stage to beta stage. Its melting point is at 1680oC and boiling point is at 3287oC.
8. The alpha-beta titanium alloy is heat treatable up to _______
Explanation: Alpha-Beta alloys are the most widely used titanium alloys. This is because they are a combination of alpha and beta alloys. Alpha alloys are stable up to 540oC but are not heat-treatable. Beta alloys are heat-treatable up to 320oC. Alpha-Beta alloys are heat-treatable up to 430oC but are more difficult to weld.
9. Beryllium is a ductile material, before turning brittle at ______
Explanation: Beryllium is a brittle material which stops it from being easily fabricated and reduces performance. It becomes more ductile between 200-400oC. However, over 500oC, it becomes brittle again.
Sanfoundry Global Education & Learning Series – Engineering Materials & Metallurgy.
To practice all areas of Engineering Materials and Metallurgy for Freshers, here is complete set of 1000+ Multiple Choice Questions and Answers.