Principle forrepeated welding method of overhead crane: weld repeatedly with heavy current main girder weld joint, correct original deformation by welding deformation single girder overhead cranegenerated by repeated welding. If it is needed to increase main girder camber, start a repeated welding on two fillet weld joints between bottom cover plate and web plate of main girder. The pressure caused by cooling shrinkage of weld joint will increase camber. If it is needed to reduce horizontal bending, start a repeated welding on two fillet weld joints between web plate at convex side and top, bottom cover plates. Weld current and length should be decided according to correction degree. Repeated correction caused by out of limits should be avoided.

 

Practices have proven that the repeated welding method is the best correction way featuring accurate and effective correction result, smooth deformation and perfect appearance. Featuring practicability, economics, simpleness, high quality, fast speed and other advantages, repeated welding method is more suitable to correct camber, horizontal bending, large height difference at the same section of two main girders of bridge crane and so on.

 

But it is not suitable in below conditions: 1. hard bending at some place of main girder; 2. main girder has a larger deformation caused by insufficient stiffness after a long-term use.