The heat treatment process generally includes three processes of heating

The workpiece is heated to 20-40°C above the temperature at which the steel begins to form austenite, and then slowly cooled after holding the temperature.. and the residual stress in the casting. If they are not tempered in time, they will tend to deform or even crack. Adjust the mechanical properties of the workpiece.

It is used to refine the coarse superheated structure of poor mechanical properties after casting, forging and welding of medium and low carbon steel. The hardness after tempering is generallyWholesale INA Bearings Manufacturers HB200-330.Those with a little mechanical knowledge should know that heat treatment is the soul that imparts the inherent quality of machinery.

The heat treatment process generally includes three processes of heating, heat preservation and cooling, sometimes only two processes of heating and cooling. For some low- and medium-carbon alloy steels used in steam turbines and boilers, normalizing is often used to obtain bainite structure, and then after high temperature tempering, it has good creep resistance when used at 400-550℃. Stress relief annealing.

Common annealing processes are: Completely annealed. For iron and steel products, the temperature at which austenite begins to form after heating is 100 to 200°C, and the inteal stress can be eliminated by cooling in air after heat preservation. This phenomenon is called secondary hardening.

Low temperature tempering: 150-250°C, M cycle, reduce inteal stress and brittleness, improve plastic toughness, have higher hardness and wear resistance. The holding time for stress relief annealing of castings is taken as the upper limit, and the cooling rate is controlled at (20-50) ℃/h, and it can be air-cooled after cooling to below 300 ℃.