Heat Treatment Process of Low Cost NM400 Steel Plate

Low cost NM400 steel plates are known for their excellent mechanical properties, such as good wear resistance, superior strength and high toughness. This is why they are widely used in wear applications such as construction, mining and quarrying. However, in order to ensure that these plates can perform as expected, they must undergo a certain series of heat treatment processes. The process used to treat these plates generally consists of four stages: normalizing, tempering, quench hardening and sub-zero treatment. In this article, we will take a look at each of these stages and how they can help to improve the properties of low cost NM400 steel plates.
    
NM400 steel plate Normalizing 
Normalizing is used to refine the microstructure of low cost NM400 steel plates and to remove any internal stresses that the plate has picked up during the manufacturing process. During the process, the plates are heated to a temperature between 1500°F and 1650°F and held at this temperature for a period of time. The longer the time, the greater the refining effect. The plate then needs to be cooled in order for the new microstructure to be retained. This normalizing step helps to improve the strength and toughness of the steel.
    
NM400 steel plate Tempering
After normalizing, the low cost NM400 steel plates need to be tempered in order to reduce their brittleness. Tempering is achieved by heating the plates to a temperature between 300°F and 800°F and holding this temperature for a certain period of time. Depending on the desired properties, either a low or high tempering temperature is used. Low tempering temperatures increase toughness, while high tempering temperatures increase strength.

NM400 steel plate Quench Hardening
Quench hardening is the next step in the heat treatment process for low cost NM400 steel plates. During this step, the plates are rapidly heated to a temperature between 1500°F and 1650°F and then quickly cooled, usually in oil or water. This rapid cooling causes the formation of hard, tempered martensite in the steel and leads to an increase in both strength and wear resistance.
    
NM400 steel plate Sub-Zero Treatment
The last step in the heat treatment process for low cost NM400 steel plates is the sub-zero treatment. During this step, the plates are placed in a special cooling bath at a temperature that is below freezing, usually between -300°F and -350°F. This serves to further refine the microstructure of the steel, resulting in an even higher strength and wear resistance.

NM400 steel plate heat treatment  Conclusion:
Low cost NM400 steel plates undergo a series of heat treatment processes in order to improve their properties. This generally includes normalizing, tempering, quench hardening and sub-zero treatment. Each of these stages is important in ensuring that the plates can perform as expected in wear applications. They also help to refine the microstructure of the steel, resulting in an increased strength and wear resistance.

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