As mentioned above, the hinge cracks at the spot welding between the shell and the reinforcing plate due to excessive stress. According to different situations, the welding repair methods are as follows:

1, when the crack is long, weld the crack on both sides of the original spot welding, then heat the reinforcing plate at the spot welding to a certain extent, and finally melt the inner and outer layers at the original spot welding and weld them together with a little covered electrode.

2. When the crack is short, lower the welding gun, aim the flame at the spot welding, and make the inner and outer layers heat up rapidly. If the outer plate has melted and the temperature of the reinforcing plate is not enough, raise the welding torch for a while, let the heat of the outer plate transfer to the reinforcing plate, and then burn it. When both layers are melted, a little covered electrode is added for welding. At this time, attention should be paid to the tilt angle of the welding nozzle and the size of the flame, so as to prevent the temperature of the reinforcing plate from burning, poor melting and weak welding; It is also necessary to avoid that the melting area of the outer plate is too large, welding repair is difficult, and the quality is affected. In the welding repair of the above two cases, in order to weld firmly, special tools can be used to hold the hinge from the outside, so that the outer layer can be tightly attached to the reinforcing plate lock. Only in this way can the welding be firm and smooth, which is conducive to knocking flat and restoring to the original state. In addition, the upper and lower ends of the hinge should be welded at 1~2 points respectively, so that the inner and outer layers can be firmly combined and the service life can be prolonged. If the lower hinge is seriously damaged, use telescopic thimble to push out the reinforcing plate from the inside of the door shell to make it close to the outer layer, which is convenient for welding.

I hope this helps.