1. Which is false statement about case hardening? Case hardening is done by
a. Electroplating
b. Cyaniding
c. Induction hardening
d. Nitriding
e. Flame hardening
Answer:
Electroplating
2. Gun metal contains
a. 70% copper and 30% zinc
b. 90% copper and 10% tin
c. 85-92% copper and rest tin with little lead and nickel
d. 70-78% copper and rest tin
e. 85-92% copper and rest zinc
Answer:
85-92% copper and rest tin with little lead and nickel
3. Which of the following is not a casting defect
a. Hot tear
b. Blow hole
c. Scab
d. Decarburization
e. Shift
Answer:
Decarburization
4. Draft on pattern for casting is
a. Shrinkage allowance
b. Identification number marked on it
c. Taper to facilitate its removal from mould
d. Increase in size of cavity due to shaking of pattern
e. For machining allowance
Answer:
Taper to facilitate its removal from mould
5. The increase in hardness due to cold working is called
a. Cold hardening
b. Hot hardening
c. Work hardening
d. Age hardening
e. Induction hardening
Answer:
Work hardening
Mechanical Engineering Online 