Preheat

- Apr 28, 2020-

Preheat


Preheating can reduce the cooling rate after welding, reduce the highest hardness of the heat-affected zone of medium carbon steel, and prevent cold cracks, which is the main technological measure for welding medium carbon steel. Preheating can also improve joint plasticity and reduce the residual stress after welding. Generally, the preheating temperature of 35 and 45 steel is 150-250 ℃. The preheating temperature can be increased to 250-400 ℃ when the carbon content is higher or the crack tendency is largely due to the thickness and rigidity.