During the seam welding of the paint chemical barrel, care should be taken to prevent cracks and damage the air tightness of the weld. The reason for the streaks of the paint chemical barrel is that the paint remaining in the nugget and spreading to the heat-affected zone embrittles the joint and causes the hand to be stressed.

The method to prevent cracks is to select the correct process parameters. Tests have proved that the smaller the penetration rate (10-26%), the smaller the crack defect. When the seam welding speed is high, the heat dissipation condition is poor, the surface is overheated, and the penetration depth is large, which is easy to produce cracks. Generally, under the condition of ensuring the diameter of the nugget and the strength of the joint, small current, low welding speed and strong external water cooling should be selected as far as possible