Engineering Materials Practice Set-2

1. The presence of hydrogen in steel causes

Improved Weldability

Embrittlement

Reduced neutron absorption cross-section

Corrosion resistance

2. Free cutting steels

Require minimum cutting force

Can be cut freely

Contain carbon in free from

Is used where rapid machining is the prime requirement

3. White cast iron

Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable

Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material

Is produced by annealing process. It is soft, tough and easily machined metal

Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron

4. When low carbon steel is heated up to upper critical temperature

The grain size increases very rapidly

There is no change in grain size

The grain size first increases and then decreases very rapidly

The average grain size is a minimum

5. In basic Bessemer process, the furnace is lined with

(C) Both (A) and (B)

(A) Silica bricks

(B) A mixture of tar and burnt dolomite bricks

(D) None of these

6. Malleable cast iron

Is produced by small additions of magnesium (or cerium) in the ladle. Graphite is in the nodular or spheroidal form and is well dispersed throughout the material

Is produced by annealing process. It is soft, tough, and easily machined metal

Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron

Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable

7. Which of the following is added in low carbon steels to prevent them from becoming porous?

Sulphur

Manganese

Phosphorus

Silicon

8. Ductile cast iron

Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material

Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable

Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron

Is produced by annealing process. It is soft, tough and easily machined metal

9. Which is false statement about annealing? Annealing is done to

Improve machining characteristic

Relieve stresses

Soften material

Harden steel slightly

10. Sulphur in steel

Lowers the toughness and transverse ductility

Reduces the grain size

Decreases tensile strength and hardness

Acts as deoxidiser

Engineering Materials Practice Set-2

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