Heat treatment is the process of heating and cooling metals to achieve desired physical and mechanical properties through modification of their crystalline structure. The temperature, length of time, and rate of cooling after heat treatment will all impact properties dramatically. The most common reasons to heat treat include increasing strength or hardness, increasing toughness, improving ductility and maximizing corrosion resistance
Heat treatment procedures
Heating : The steel material could be heated below the critical point or above critical point. The former heating way can stabilize structure and eliminated the residual stress. The latter way can make material austenitizing.
Heat preservation: The purpose of heat preservation is to uniform the heating temperature of steel material, then it will get a reasonable heating organization.
Cooling: The cooling process is the key process in heat treatment, it determines mechanical properties of steel pipe after cooling process.