Mechanical Metallurgy Mcqs


The motor vehicle crank shaft is made by which of the following method?

A) Forging B) Casting
C) Extrusion D) Sheet metal formation
Answer & Explanation Answer: A) Forging

Explanation: The crank shaft undergoes repeated loading cycle, so the directional arrangement of grain has to be avoided. Hence, the forging is the best possible method to produce the crank shaft.

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The base of heavy machinery is made by which of the following metal?

A) Stainless Steel B) Mild steel
C) Cast iron D) Nickel
Answer & Explanation Answer: C) Cast iron

Explanation: The cast iron has graphite flakes present in it, which acts as the stress absorber, hence the vibration is absorbed and dumping capacity is improved.

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The orange peeling effect of the deep-drawn cup can be eliminated most effectively by _______

A) Increasing the thickness of the sheet B) Decreasing the thickness of sheet
C) Using large grain size sheet D) Using smaller grain size sheet
Answer & Explanation Answer: D) Using smaller grain size sheet

Explanation: The sheet metal with larger grain size on deformation tends to behave differently to different amount of load. The larger size grain is less likely to align themselves along the curvature of deep drawn cup, this causes surface irregularity and peeling of surface in extreme case. So this can be avoided by using small grain size sheet which can be easily aligned along the deep cup curvature.

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In which of the following method, the female die is not required?

A) Sheet metal rolling B) Tube extrusion
C) Stretch forming D) Pressure die forging
Answer & Explanation Answer: C) Stretch forming

Explanation: In stretch forming, the sheet metal is mounted on the curvature tome shaped support and single die is rolled over the surface to shape the material into the desired shape.

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If the minimum bend radius of the material is small, this indicates that the ________

A) Metal is highly ductile in nature B) Metal is highly brittle in nature
C) Metal will easily crack on bending D) Metal will have high tensile strength
Answer & Explanation Answer: A) Metal is highly ductile in nature

Explanation: The minimum bend radius is the minimum radius of curvature to which the metal can be bend without causing fracture of surface cracks. Hence, if the metal is extremely ductile the minimum bend radius can be close to zero also, and for brittle metal, it will be very high.

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The conventional strain along the length of the sheet which is subjected to bending is given as ____
Assume height of sheet is h and radius of the bend is R.

A) R/h B) 1/[(2R/h) +1]
C) 1/(R+h) D) R+h/h
Answer & Explanation Answer: B) 1/[(2R/h) +1]

Explanation: When the sheet metal is bent, the outer surface elongates whereas the inner surface compresses. This generates strain on the inner and outer surface of equal magnitude but opposite in sign. This strain is calculated to be equal to 1/[(2R/h) +1].

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A steel sheet of thickness 25 mm is sheared with a knife, and the fracture length is 50 mm. Find the shear force required, if the tensile strength of steel is 250 MPa?

A) 500 kN B) 250 kN
C) 218 kN D) 238 kN
Answer & Explanation Answer: C) 218 kN

Explanation: Not available for this question

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The clearance between the stationary blade and moving blade should always be low to obtain a smooth fractured surface.

A) True B) False
Answer & Explanation Answer: B) False

Explanation: There is an optimum level of clearance which needs to be provided to get the smooth fractured surface. This depends upon the plane on which the fracture takes place concerning tool position.

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