Effect of Tempering Temperature on Microstructure and Properties of High Carbon Wear-resistant Steel

High carbon wear-resistant steel is a type of steel alloy that offers superior toughness, hardness, and wear resistance. It has excellent corrosion resistance, high carbon content and is comparatively low cost compared to other wear resistant steels. These properties make it a popular choice in many industries, such as shipbuilding, offshore oil and gas exploration and production, and mining.
    
Tempering is a common heat treatment process used to alter the physical and mechanical properties of steel. During tempering, the steel is heated to a temperature below its critical point and then cooled quickly. Depending on the temperature chosen for tempering, different microstructures and properties can be attained.
    
Tempering temperature plays an important role in determining the microstructure and various properties of high carbon wear-resistant steel. Generally, a lower tempering temperature results in a lower-strength steel that has lower hardness and wear resistance. On the other hand, a higher tempering temperature causes an increase in strength and hardness, but a decrease in wear resistance.
    
Going too high on tempering temperature can also cause the steel to become embrittled due to the formation of martensite during tempering. Thus, the tempering temperature needs to be chosen carefully to ensure that an optimal combination of strength, hardness and wear resistance is achievable.
    
At lower tempering temperatures, bainite, ferrite, and cementite form in high carbon wear-resistant steel. These microstructures are far less wear-resistant than the martensite usually formed at higher temperatures, and can make the steel susceptible to cracking under high stress. In order to avoid deformations, it is recommended to temper high carbon wear-resistant steel at a temperature of 550-650°C.
    
At temperatures ranging from 650-750°C, an optimal mix of hardness, toughness, and wear resistance can be achieved in high carbon wear-resistant steel. In this range, the steel forms a mix of bainite, ferrite, and martensite. This microstructure is highly wear resistant, allowing the steel to be used in the most demanding applications.
    
At temperatures above 750°C, the tempering can cause an increase in hardness as well as a decrease in toughness. Above this temperature, the steel will become increasingly prone to cracking, making it unfit for use in many applications.
    
In summary, temperature plays a major role in determining the properties of high carbon wear-resistant steel. Lower tempering temperatures can result in lower strength and lesser wear resistance, while higher temperatures can cause increased hardness and a decrease in toughness. The best way to ensure the optimal balance of all the necessary characteristics is by tempering at 650-750°C.

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