This set of Mechanical Metallurgy Multiple Choice Questions & Answers (MCQs) focuses on “Metal Working Fundamentals – Temperature in Metal Working”.
1. The metal forming process blanking is associated with which type of force?
a) Shear force
b) Tensile force
c) Compressive force
d) Spring back force
Explanation: The blanking is the operation of removal of the useful part from a sheet or a plate by using a planking tool. The nature of force in blanking is pure shear in nature.
2. The nature of force in extrusion process is ________________
a) shear force
b) tensile force
c) compressive force
d) spring back force
Explanation: The nature of force is compressive in the extrusion process. The wall of die in case of extrusion applies the compressive force on the metal, which causes it to shrink and reduce in its diameter.
3. For forging the bolt head on the of hexagonal shape on the thick plate, the best method is ______
a) drop forging
b) press forging
d) progressive forging
Explanation: For fixing a screw on the plate, the applied load should be slow and firm, so closed-die press forging is the best method to achieve the suitable results.
4. For which of the following method, the lubrication of die and the workpiece is required?
c) Wire drawing
d) Sheet metal forming
Explanation: The lubrication is required in the process where the relative contact area and contact time between the sample and die are maximum. So the lubrication is applied to lower the friction between the die and workpiece.
5. At what temperature, the hot extrusion process is generally carried out?
a) At room temperature
b) Below room temperature
c) Half of the melting point
d) Near the melting point
Explanation: The hot extrusion process is carried out to avoid the breaking of the workpiece. Along with that, in hot working the required stress to cause the deformation also significantly reduces, hence it is carried out around 0.5 Tm.
6. In rolling of metal, the total possible reduction in second pass is more significant than the reduction possible in first pass.
Explanation: The first pass in rolling is to align the grain in favourable direction and giving the texture to the workpiece for further working; the total possible reduction is very less in first pass. While in second the reduction ratio is high.
7. The hot working of the material is carried out above the recrystallization temperature of the material.
Explanation: The hot working of the material is carried out above the recrystallization temperature of the given material. For low melting point material, the hot working temperature is room temperature.
8. The surface finish of workpiece in hot working is _______ the surface finish in cold working.
a) better than
b) worse than
c) same as
d) relative to
Explanation: The surface finish in cold working is better than hot working, because in hot working at the higher temperature, the surface oxidation is predominant and the oxide layer is formed on the metal which reduces the surface properties.
9. Which of the following property of the material does not affect its metalworking behaviour?
a) Yield strength
b) Ultimate tensile strength
c) Endurance limit
d) Strain hardening rate
Explanation: The rate of strain hardening is the most significant property that affects the metalworking behaviour, but the endurance limit is associated with fatigue strength of the material. In the case of repetitive loading, it does not affect metalworking.
10. For which of the following material, room temperature working is not equivalent to hot working?
Explanation: The hot working temperature is decided based on the recrystallization temperature of the metal. The zinc, tin, lead has recrystallization temperature below room temperature, so room temperature working is also equivalent to hot working.
11. In which of the following furnace, stirring action while mixing the different alloys is most efficient?
a) Muffle furnace
b) Cupola furnace
c) Induction furnace
d) Arc furnace
Explanation: The induction furnace generates the effect of eddy current induction which is circular around the crucible; hence everything inside the crucible once melted will be stirring automatically which provides efficient mixing of the materials.
Sanfoundry Global Education & Learning Series – Mechanical Metallurgy.
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