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Statement (I): Salts like sodium chloride, sodium hydroxide when added to water to use as quenching media, cooling rate of quenching media will be increased. Statement (II): When salts are added to water, during quenching, distortion and crack appearance in the quenched steel components reduces.

Statement (I): Salts like sodium chloride, sodium hydroxide when added to water to use as quenching media, cooling rate of quenching media will be increased. Statement (II): When salts are added to water, during quenching, distortion and crack appearance in the quenched steel components reduces. Correct Answer Statement (I) is true but Statement (II) false 

Concept:

Quenching is the rapid cooling of a workpiece in water, oil or air after heating the material to a certain temperature (depending on the material) to obtain certain material properties.

Quenching is slow in oils but quenching metal in oil is the most popular method because it diminishes risk of cracking and warping.

Fastest cooling is provided by salt solutions as they suppress the bubble formation on the metal surface. Also the salts does not affect the crack appearance and properties of metals.

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