Research on heat treatment process of high strength and toughness wear-resistant cast steel

Heat treatment is one of the most effective ways to improve the performance of wear-resistant cast steel. Heat treatment of high-strength and toughness wear-resistant cast steel can improve its properties such as high strength, toughness and wear resistance. Therefore, the heat treatment process of high-strength and toughness wear-resistant cast steel is of great significance.
    
The heat treatment of high-strength and toughness wear-resistant cast steel usually consists of three parts: quenching, tempering and quenching-tempering.
    
Quenching is to heat the workpiece to the transformation point or a certain temperature higher than the transformation point, and then quench it quickly to make the workpiece get a large amount of austenite transformation, so that the workpiece surface layer is Martensite, which can improve the surface hardness and wear resistance of the workpiece; At the same time, due to the in-phase transformation above the transformation point, it can improve the mechanical properties of the workpiece, especially its anti-plastic deformation ability and strength.
    
Tempering is to further improve the toughness and plasticity of the quenched and hardened parts. Generally, the tempering temperature should be higher than 300°C, and the tempering time is usually 1~3 hours. After tempering, the hardness of the outer layer of the workpiece will decrease, but the strength, toughness and wear resistance of the workpiece will be improved to certain extent.
    
Quenching tempering can further improve the strength, toughness and wear resistance of high-strength and toughness wear-resistant cast steel. After quenching, tempering should be carried out first, and then quenching should be performed again. It has the advantages of "two hundred and fifty fire"--that is, before the tempering temperature is affected, the hardness of the surface layer of the workpiece is kept high, which can not only improve the wear resistance of the workpiece, but also ensure its strength and toughness.
    
In order to get the required properties of high-strength and toughness wear-resistant cast steel, it is very important to strictly control the parameters in the heat treatment process, including the starting temperature and cooling rate of the workpiece during the quenching process, the quenching medium and temperature, the tempering temperature, time and number of times.
    
In addition, the heat treatment process of high-strength and toughness wear-resistant cast steel also includes other processes, such as high-frequency quenching and various surface treatments. Through reasonable heat treatment process, high-strength and toughness wear-resistant cast steel can obtain good comprehensive performance.

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