The heat treatment hardness of the mold is a very important mechanical property index. The insufficient hardness or uneven hardness after the heat treatment of the mold will reduce the wear resistance and fatigue strength of the mold, leading to early failure of the mold and severely reducing the service life of the mold. What are the reasons why the mold hardness is insufficient or uneven?
1) The mold section is large, and the hardenability of the steel is poor.
2) The segregation of carbides in the original microstructure of the die steel is serious or the structure is coarse. There is segregation and aggregation of graphite carbon and carbide in the steel.
3) The die forging process is not correct. After forging, no good spheroidizing annealing is performed, so that the spheroidized structure of the die steel is poor.
4) The decarburized layer produced when the surface of the mold is not removed by annealing or quenching.
5) The mold quenching temperature is too high, the amount of retained austenite after quenching is too much; or the quenching temperature is too low, the heating and holding time is insufficient, so that the phase transformation of the mold steel is incomplete.
6) Cooling speed is too slow after the mold is quenched and heated, the grading and isothermal temperature is too high or the time is too long, and the quenching cooling medium is not properly selected.
7) Too little water in the alkali bath, or too much impurities in the quenched cooling medium, or aging in the quenched cooling medium.
8) The temperature of the quenched cooling medium after mold quenching is too high and the cooling is insufficient.
9) Incomplete tempering and tempering temperatures are too high.
This article is edited by Zhongshan Huashi Fushun Special Steel Technology Department. Please call for more details.
Contact: Mr. Chen 18988586811
Service Hotline
Address: Road 105, Pingdong Industrial Zone, Sanxiang Town, Zhongshan City, Guangdong Province
1) The mold section is large, and the hardenability of the steel is poor.
2) The segregation of carbides in the original microstructure of the die steel is serious or the structure is coarse. There is segregation and aggregation of graphite carbon and carbide in the steel.
3) The die forging process is not correct. After forging, no good spheroidizing annealing is performed, so that the spheroidized structure of the die steel is poor.
4) The decarburized layer produced when the surface of the mold is not removed by annealing or quenching.
5) The mold quenching temperature is too high, the amount of retained austenite after quenching is too much; or the quenching temperature is too low, the heating and holding time is insufficient, so that the phase transformation of the mold steel is incomplete.
6) Cooling speed is too slow after the mold is quenched and heated, the grading and isothermal temperature is too high or the time is too long, and the quenching cooling medium is not properly selected.
7) Too little water in the alkali bath, or too much impurities in the quenched cooling medium, or aging in the quenched cooling medium.
8) The temperature of the quenched cooling medium after mold quenching is too high and the cooling is insufficient.
9) Incomplete tempering and tempering temperatures are too high.
This article is edited by Zhongshan Huashi Fushun Special Steel Technology Department. Please call for more details.
Contact: Mr. Chen 18988586811
Service Hotline
Address: Road 105, Pingdong Industrial Zone, Sanxiang Town, Zhongshan City, Guangdong Province
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