Engineering Materials MCQ Questions & Answers | Mechanical Engineering Page-4 section-3

16.
Smelting is the process of

A. Removing the impurities like clay, sand etc. from the iron ore by washing with water

B. Expelling moisture, carbon dioxide, sulphur and arsenic from the iron ore by heating in shallow kilns

C. Reducing the ore with carbon in the presence of a flux

D. All of the above

A. Hardening surface of work-piece to obtain hard and wear resistant surface

B. Heating and cooling rapidly

C. Increasing hardness throughout

D. Inducing hardness by continuous process

A. Dipping steel in cyanide bath

B. Reacting steel surface with cyanide salts

C. Adding carbon and nitrogen by heat treatment of steel to increase its surface hardness

D. Obtaining cyanide salts

A. In which parts are not loaded

B. In which stress remains constant on increasing load

C. In which deformation tends to loosen the joint and produces a stress reduced

D. Stress reduces on increasing load

A. Cementite

B. Free carbon

C. Flakes

D. Spheroids

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