Analysis on heat treatment process of low alloy wear-resistant cast steel

Low alloy wear-resistant cast steel is widely used in various fields due to its excellent wear resistance, impact resistance and good processability. Proper heat treatment process can greatly improve its performance.
    
Heat treatment of low alloy wear-resistant cast steel is mainly aimed at refining grain structure and improving its wear resistance and impact toughness. Generally speaking, its heat treatment is quenching and tempering, quenching after austempering or martempering.
    
The first step of heat treatment process is austenitizing. Its austenitizing temperature should not be lower than 980℃. Holding time should be enough to complete austenitizing. Generally speaking, this process should be completed in a few minutes.
    
Then, the austenitized piece should be quenched in water, oil or quenching medium. The quenching temperature of furnace should not be higher than 880℃ when quenching in oil or quenching medium. Quenching in water should also observed corresponding quenching temperature.
    
Finally, tempering process should be adopted to reduce stress, refine grain structure and improve toughness. Generally speaking, tempering can be carried out by furnace or hot air. Temperatures for air tempering are generally 400~500℃, and for furnace tempering are generally 400~650℃.
    
The heat treatment process of low alloy wear-resistant cast steel is shown in Fig 1.
    
The heat treatment process of low alloy wear-resistant cast steel mainly including austenitizing, quenching and tempering. If the heat treatment process is reasonable, the grain structure of steel can be refined greatly and its strength and wear resistance can be improved. However, if the heat treatment process is not reasonable, the performance of steel will be greatly reduced. Therefore, the correct heat treatment process is important for the use of low alloy wear-resistant cast steel.

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