GATE 2017-2018 :: GATE Metallurgical
- Fracture stress for a brittle material having a crack length of 1 μm is 200 MPa. Fracture stress for the same material having a crack length of 4 μm is
- The flow stress of an alloy varies with strain rate MPa. When the alloy is hot extruded from 10 cm diameter to 5 cm diameter at a speed of 2 cm/s, the flow stress is
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Determine the correctness or otherwise of the following Assertion (a) and Reason (r). Assertion : During rolling, front tension and (or) back tension are (is) employed to decrease rolling load.Reason : Roll pressure decreases due to lowering of flow stress as a result of front tension/back tension.
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Match the defects listed in Group I with the processes listed in Group IIGroup I Group IIP. Cold shut 1. RollingQ. Earing 2. ForgingR. Alligatoring 3. Deep drawingS. Shrinkage porosity 4. Fusion welding
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A steel ball (density Ïsteel = 7200 kg/m3) is placed in an upward moving liquid Al (density ÏAl = 2360 kg/m3, viscosity μAl = 1 * 10“3 Pa.s and Reynolds number = 5 * 105). The force (F) exerted on the steel ball is expressed as F = f Ï€ R2(ÏAl v2/2)where, f is friction factor (=0.2), v is the velocity of liquid Al and R is the radius of steel ball.The force exerted on the steel ball is
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A steel ball (density Ïsteel = 7200 kg/m3) is placed in an upward moving liquid Al (density ÏAl = 2360 kg/m3, viscosity μAl = 1 * 10“3 Pa.s and Reynolds number = 5 * 105). The force (F) exerted on the steel ball is expressed as F = f Ï€ R2(ÏAl v2/2)where, f is friction factor (=0.2), v is the velocity of liquid Al and R is the radius of steel ball.The terminal velocity of a fine spherical steel particle having diameter dp, in μm range, if allowed to fall in a quiescent liquid Al bath, is
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A material with grain size of ASTM No. 6 has a lattice frictional stress 100 MN/m2 and locking parameter (Hall-Petch constant) 0.10 MN/m3/2 Grain size of the material is approximately
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A material with grain size of ASTM No. 6 has a lattice frictional stress 100 MN/m2 and locking parameter (Hall-Petch constant) 0.10 MN/m3/2 Yield strength of the material is approximately