Normalizing process

Normalizing process is heat the steel to Ac3 ( Or Acm) More than 30 ~ 50 ℃, the heat preservation after the right time, in the stillness of the air cooling heat treatment process. The steel heating to 100 ~ 150 ℃ above Ac3 normalizing is called high temperature normalizing. For medium and low carbon steel casting, forging, the main purpose of normalizing is refined. After compared with annealing, normalizing pearlite lamella is fine, ferrite grain size is small, thus higher strength and hardness. Low carbon steel because of the low hardness after annealing, produce the phenomenon that stick knife when cutting, cutting performance is poor, improve hardness by normalizing, can improve the cutting performance, some carbon structural steel parts in normalizing can substitute for conditioning, simplify the heat treatment process. Hypereutectoid steel is heat knife Acm above, make originally net-like cementite absorbed into austenite, and then use faster cooling, inhibition of cementite in austenite grain boundary precipitation, which can eliminate the carbide network, improve the organization hypereutectoid steel. Weldment parts with weld strength requirements is to improve the weld microstructure of fire, ensure the weld strength. Repair parts in the process of heat treatment must be normalized processing, the structure of the required mechanical performance index components should be carried out after normalizing conditioning can meet the requirements of mechanical properties. Medium and high alloy steel and large forgings after normalizing must plus high temperature tempering to eliminate internal stress is generated when the fire. Some steel alloy forging parts are produced when the martensitic transformation, the formation of hard tissues. In order to eliminate this kind of undesirable tissue taken normalizing, higher than the normal normalizing temperature 20 ℃ or so for normalizing heat insulation. Normalizing process is simple, is advantageous to the forging heat in the fire, can save energy and shorten the production cycle. Normalizing process and also produce tissue defect, improper operation and annealing are similar, remedial method is basically the same.