heat treatment hardening is one of the commonly used processes of metal steel. In the process of heat treatment quenching, we will meet a variety of problems. The following are the common questions and answers for heat treatment quenching.
The main causes of quenching cracking include the size and shape of workpiece, carbon content, cooling method and pre-treatment method, etc. The main causes of quenching crack include the size and shape of workpiece, carbon content, cooling mode and pre-treatment method, etc. The heat treatment of iron and steel will produce quenching crack, which leads to abnormal stress during quenching process, and this abnormal stress is related to the process of deformation of Ma Tian bulk body. Usually, the steel does not break at the beginning of the deformation of Ma Tian bulk body. It is about 50% (temperature about 150 ℃ at this time), that is, quenching will occur before the end of quenching. Therefore, the quenching process should be rapidly cooled at high temperature and slowly cooled at low temperature. If we can grasp the key of “quick first and then slow”, the quenching crack can be minimized.
Will the microstructure before quenching affect the quenching crack? The structure before quenching will of course affect the success or failure of quenching. The most normal pre-structure should be normalized structure or annealed structure (Bolais structure). If the microstructure is superheated before quenching, the spheroidal structure will have different results. The superheated structure is easy to produce quenching crack, while the spheroidal structure can be hardened uniformly to avoid quenching crack and bending. Therefore, it is one of the important quenching techniques that tool steel or high carbon steel can be spheroidized before quenching. Spherical carbides can be obtained by spheroidizing annealing or spheroidizing treatment. If carbides exist in reticulated structure, they are easy to be quenched and cracked.
Overseas manager: Tom Wang
Phone: 0086-13303078975(whatsapp, wechat,line)
Specialist of bar heat treatment furnace in China; Glad to be your business partner in induction heating field.
Post time: 04-25-2019