3. The stress relievingThe stress relieving is also called low temperature annealing (or high temperature tempering), the annealing is mainly used to eliminate the casting, forging, welding parts, rolling, the residual stress of cold-drawn pieces, etc.If these stress will not be eliminated, will cause the steel after a certain period of time, or during subsequent machining deformation or cracks. Quenching, the most commonly used cooling medium is salt water, oil and water.Brine quenching workpiece, easy to get high hardness and smooth surface, it is not easy to produce soft point of quenching is not hard, but it is easy to make the workpiece deformation is serious, even cracking.Oil as quenching medium is only applicable to the stability of the supercooled austenite bigger some alloy or carbon steel workpiece quenching of small sizes.Qingdao hexing main production furnace roll, radiant tube, high temperature resistant alloy furnace tube, heat-resistant steel castings, and other industrial products, through strict manufacturing and testing, quality assured, welcome to buy.