Welding repairing process is a technology. Most of the materials of tractor's large and small reducer gears and transmission sliding gears are made by 20Cri3 and 18CrMnTi forged steel. For the uniform wear of the gears after long-term use, PTA plasma powder surfacing method can be used for repair. The repair process is as follows:
1. Clean the tooth surface before welding and grind the tooth surface with a small amount of angle grinding wheel to expose the tooth surface to metallic luster. At the same time, check the tooth surface for no cracks.
2. Annealing before welding, its role is to eliminate fatigue stress and improve the plasticity of the material. The method is to put the gear in the annealing tank, fill it with river sand, add a small amount of pig iron scraps or crushed charcoal to the river sand, then put the annealing tank in the annealing furnace, keep it at 780 ~ 840 degrees for 2 hours, and cool it with the furnace.
3. Select the special high-entropy alloy spray welding powder of Hunan WISE New Material Technology Co., Ltd. The welding powder should be dried before welding, and the powder should be fed slowly with a small current during welding.
4. Welding from the root of the tooth along the width of the tooth. Each tooth is welded about 5 times, including 4 tooth surfaces and 1 tooth crest. In order to reduce the deformation, all the teeth on the gear are welded after the first pass, and then the second pass is welded. Each weld pass should overlap by 1/2 width. Except for the last surfacing tooth tip, symmetrical skip welding may not be used, and the symmetrical skip welding sequence should be adopted for the remaining surfacing welding to prevent deformation. The welding direction of each pass should be opposite to the previous one. After the surfacing of the gear is started, it must not be stopped halfway, and it should be completed at one time.
5. Annealing after welding to reduce hardness and facilitate mechanical processing.
6. After mechanical processing, carry out 600 degree tempering, heat preservation for 2 hours, and natural cooling to improve the surface hardness.
7. Finally, carry out low temperature tempering to relieve stress. The tempering temperature is 180.20 for 1.5h, and the furnace is air-cooled. For the tooth surface wear of the Dongfanghongyi-54 tractor drive wheel, it can be repaired with a special high-entropy alloy spray welding powder of medium hardness of Hunan WISE New Material Technology Co., Ltd., and the tooth surface can be continuously welded, and the model is used to control the stack Welded tooth shape. It can be used without any processing after surfacing.
Generally speaking, the service life of gears repaired by surfacing is greatly increased, and the cost of repair is also much lower than the cost of purchasing new products.