512. Electro-discharge machining uses the following dielectric fluid
A.Water
B.Acqueous salt solution
C.Sodium hydroxide
D.Kerosene

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513. Best coolant and lubricant for brass, copper, bronze and monel metal is
A.Water, soluble Oils or sulphur-based mineral oils
B.Mineral and fatty oils
C.Soluble oil
D.Dry

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514. In ion beam machining process, the metal is removed by
A.Sputtering process
B.Pulsed magnetic field
C.Thermoelectric process
D.All of the above

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515. The type of the chip produced when cutting cast iron is
A.Continuous
B.Discontinuous
C.With built up edge
D.Any one of above depending on other factors

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516. Best coolant and lubricant for steel and wrought iron is
A.Water soluble oils or sulphur-based and mineral oils
B.Mineral an fatty oils
C.Soluble oils
D.Dry

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517. Crater wear occurs mainly due to following phenomena
A.Abrasion
B.Diffusion
C.Oxidation
D.Adhesion

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518. Chips with built up edge can be expected when machining
A.Hard material
B.Brittle material
C.Tough material
D.Ductile material

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