回火的感化(国外英文资料).docVIP

回火的作用(国外英文资料) The effect of tempering Also called PeiHuo. A kind of metal heat treatment process. Will be reheated after hardening of the workpiece to the appropriate temperature below the lower critical temperature, heat preservation for a period of time after cooling in air or water, oil and other medium of metal heat treatment. The hardened alloy workpiece is heated to the appropriate temperature for several times, then slowly or rapidly cooling. It is commonly used to reduce or eliminate the internal stresses in hardened steel parts, or decrease their hardness and strength to improve their ductility or toughness. According to different requirements, low temperature tempering, medium temperature tempering, or high temperature tempering. Usually as the tempering temperature rises, the hardness and intensity decrease, the ductility or toughness gradually increase. The steel workpiece has the following characteristics after the quenching: it is organized by the martensite, the bainite and the residual austenitic body. There are major internal stresses. The mechanical properties cannot meet the requirements. As a result, steel work is tempered by tempering. Role in the effect of tempering is: (1) improve the stability of organization, organization change in the in use process is no longer of components, so that the workpiece geometry size and stable performance. Eliminate internal stress in order to improve the performance of the workpiece and stabilize the geometry of the workpiece. The mechanical properties of steel are adjusted to meet the requirements. Tempering have the effect, because the temperature rises, the atomic activity, iron, carbon and other alloying elements in steel atoms may spread rapidly, and the implementation of atoms rearrange the combination, so that the unstable unbalanced organization gradually transformed into a stable balance. The elimination of internal stress is also related to the decrease in metal strength when temperature rises. When