1. Which of the following are true?
a) 7C4 grade steel is more ductile than 10C4
b) Yield strength of 40C8 is greater than of 30C8
c) Hardness of 30C8 is greater than of 40C8
d) None of the mentioned
Explanation: The number before “C” indicates measure of carbon. Hence a) is true as higher the carbon, lower the ductility.
2.In the designation “xCb” which of the following are true?
a) x indicates 100 times the average % of carbon
b) b indicates 100 times the average percentage of manganese
c) x indicates 10 times the average percentage of carbon while b indicates 100 times the average percentage of manganese
d) b indicates 100 times the average % of carbon
Explanation: X indicates 100 times carbon % and b indicates 10 times manganese %.
3. Which of the steel in given options is best suited for auto mobile bodies and hoods?
a) 7C4
b) 10C4
c) 30C8
d) 40C8
Explanation: For automobile application like manufacturing bodies, ductile material is preferred.
4. Which of the following steel given in options respond fastest and easily to heat treatment?
a) 7C4
b) 10C4
c) 30C8
d) 40C8
Explanation: Alloys with higher carbon % respond willingly to heat treatment.
5. Which of the following given steels is popular with the name of machinery steel?
a) Low carbon steel
b) Medium carbon steel
c) High carbon steel
d) None of these
Explanation: It has ductility and can be heat treated easier than low carbon steel.
6. Cast steel components do not exhibit the effect of directionality on mechanical properties.
a) True
b) false
Explanation: In casting process, there is no control over the fibre structure, thus non directional characteristics for cast steel components.
7. During solidification, cast steel shrinks to quite a great extent
a) True
b) false
Explanation: Excessive contractions observed in cast steel.
8. Relative density of aluminium is roughly _______ of steel
a) one-third
b) one-fifth
c) one-tenth
d) equal
Explanation: Aluminium alloy=2.7 Steel=7.9
9. Which of the following statement is true
a) Cast aluminium alloys are specified by a four digit system while wrought alloys by a five digit system
b) Cast aluminium alloys are specified by a five digit system while wrought alloys by a four digit system
c) Cast aluminium alloys are specified by a six digit system while wrought alloys by a five digit system
d) Cast aluminium alloys are specified by a five digit system while wrought alloys by a six digit system
Explanation: Standard set for nomenclature.
10.Which of the following are true for aluminium
a) Low specific gravity
b) Corrosion resistance
c) High thermal conductivity
d) All of the mentioned
Explanation: All are properties of aluminium.