Salt quenching heat treatment：The salt quenching and heat treatment parts are produced by intelligent controlled atmosphere roller bottom quenching and tempering automatic production line. They are electrically heated and quenched in a closed nitrate tank. The nitrate salt cleaning solution can be returned to the quenching tank for reuse after being separated by brine. Achieve zero discharge of salt and be green. Full computer automatic control, salt bath cooling speed adjustable, good hardenability, good surface quality, small heat treatment deformation, suitable for thin wall and medium and large bearing ring heat treatment, product quality is stable, low energy consumption, no pollution ,high productivity.