Influence of Improper Heat Treatment Process Operation on NM450

What kind of impact will it have on NM450 steel plate when the heat treatment operation is improper? This article summarizes the following five main situations:
1.Quenching cracking. This kind of situation is generally seen more often. Quenching cracks of NM450 steel plate are mostly caused by improper cooling operation during cold treatment or excessive heating during heating. It may also be related to the design factors of the NM450 steel plate.

2.Insufficient hardness. For the insufficient hardness of NM450 steel plate, it may be caused by improper control of quenching temperature during heat treatment. Too high or too low quenching temperature of NM450 steel plate will cause insufficient hardness. In addition, it may be related to the tempering temperature setting for NM450 steel plate. At the same time, the pre-cooling time is too long during cooling or the cooling medium is not selected properly.

3.Appearance deformation. It is difficult to ensure the good shape of NM450 steel plate during the heat treatment process. Generally, the shape deformation is related to the large and small martensitic phase transformation.

4.Insufficient toughness. This phenomenon is generally caused by the high quenching temperature of NM450 steel plate and the long time of maintaining high temperature. Or caused by improper tempering operation.

5. Decarburization. mainly refers to the phenomenon that part or all of the carbon on the surface of NM450 steel plate is lost during the heating or heat preservation process of the NM450 steel plate. This phenomenon generally has a relatively large impact on the performance of NM450 steel plates.