302. In nitriding steel components, the following atmosphere is generally used in the furnace
A.Inert
B.Ammonia
C.Liquid nitrogen
D.Carbon

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303. After annealing a non-ferrous metal, surface oxides formed on the metal are
A.Removed with coarse emery cloth
B.Left on the metal to protect the surface
C.Pickled in acid and then removed
D.Hammered intathe surface

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304. Pick up the wrong statement. Annealing results in
A.Refining grain structure
B.Relieving internal stresses
C.Improving wear resistance
D.Improving machinability

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305. The effect of alloying silicon to copper is
A.To raise hardness
B.To impart free-machining properties
C.To improve hardness and strength
D.To increase strength and ductility (if added upto 10-30%)

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306. In ductile cast iron, the free carbon is distributed throughout the mass in the form of
A.Needles
B.Flakes
C.Nodules
D.Crystals

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307. The portion of the part not to be hardened in nitriding process is covered by a layer of
A.Asbestos
B.Tin
C.Copper
D.Aluminium

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308. The effect of alloying tin to copper is
A.To raise hardness
B.To impart free-machining properties
C.To improve hardness and strength
D.To increase strength and ductility (if added upto 10-30%)

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