Analysis of tempering process in slow cooling pit of high strength wear-resistant steel WZB-NM360A
To improve the comprehensive performance of high strength wear-resistant steel WZB-NM360A, slow cooling pit tempering is generally required. The slow cooling pit tempering process of high-strength wear-resistant steel WZB-NM360A is shown in Figure 1. The slow cooling pit tempering process consists of heating, water quenching and tempering.
First of all, high-strength wear-resistant steel WZB-NM360A shall be heated and heated uniformly to a temperature of 850 - 860 °C. After the temperature is reached, the preheating time should not be too long, generally 5 - 10 minutes, in order to reduce the over-tempering and produce the hypereutectoid structure.
Secondly, high-strength wear-resistant steel WZB-NM360A that has been heated in the furnace shall be immediately placed in the water-cooled trough or the water-cooled oil tank and quenched. This can form martensite in the material, so that the material has the required strength. At this time, in order to effectively cool the workpiece, it is necessary to use a certain amount of forced cooling for the workpiece.
Finally, after the water quenching, high-strength wear-resistant steel WZB-NM360A is placed in the slow cooling pit for tempering. The slow cooling pit is an environment with a temperature of about 500°C, and its cooling rate is slow. When the temperature decreases to theMs point of the material, the material is taken out for air cooling, so that the material is tempered once and the temperature of the material is even.
In general, the tempering process in the slow cooling pit can form tempered hardened structure with fine and uniform chmal interface, reduce the hardenability of the material, and achieve higher comprehensive performance. However, due to the slow cooling rate of the slow cooling pit, the tempering time needs to be properly controlled to prevent over-tempering.
It can be seen from the above analysis that the slow cooling pit tempering of high-strength wear-resistant steel WZB-NM360A is a necessary and important process for improving the comprehensive performance of the material. The slow cooling rate of the slow cooling pit can effectively form martensite and tempered martensite structure of the material, which can make the material obtain the highest hardness and wear resistance, and achieve the ultimate performance of the material. It important to note that, this tempering process need to be properly controlled to avoid over-tempering and affecting the performance of the material.
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