In steel pipe welding operations, defects such as flashing, burn-through, incomplete penetration, recession, slag inclusion, and poor forming often occur. The main reason for these defects is that they are not good at observing the temperature of the molten pool during the welding operation. The above defects are caused by the lack of control of the temperature of the molten pool. The temperature of the molten pool directly affects the welding quality.
The temperature of the molten pool is high, the molten pool is larger, the molten iron has good fluidity and is easy to fuse, but when the temperature is too high, the molten iron is easy to drip. The back side of surface welding double-sided forming is easy to burn through, forming flash, and the forming is difficult to control, the plasticity of the joint decreases, and the bending is easy to crack. When the temperature of the molten pool is low, the molten pool is smaller, the molten iron is darker, and the fluidity is poor. Defects such as incomplete penetration, lack of fusion, and slag inclusion are prone to occur.