64. Cyaniding is the process of
A.Dipping steel in cyanide bath
B.Reacting steel surface with cyanide salts
C.Adding carbon and nitrogen by heat treatment of steel to increase its surface hardness
D.Obtaining cyanide salts

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65. Induction hardening is the process of
A.Hardening surface of workpiece to obtain hard and wear resistant surface
B.Heating and cooling rapidly
C.Increasing hardness throughout
D.Inducing hardness by continuous process

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66. Process of austempering results in
A.Formation of bainite structure
B.Carburised structure
C.Martenistic structure
D.Lamellar layers of carbide distributed throughout the structure

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67. The surface hardness of the following order is achieved by nitriding operation
A.600 VPN
B.1500 VPN
C.1000 to 1100 VPN
D.250 VPN

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68. Hardness of martensite is about
A.RC 65
B.RC 48
C.RC 57
D.RC 80

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69. Weld decay is the phenomenon found with
A.Cast iron
B.Stainless steel
C.Non-ferrous materials
D.Wrought iron

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70. Materials after cold working are subjected to following process to relieve stresses
A.Hot working
B.Tempering
C.Normalising
D.Annealing

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