How Henan Huachuang Metal Material Trading Co., Ltd. repaired babbitt tin base alloy bearing bush. The running equipment was shut down due to bush burning, and the babbitt bearing bush was damaged due to vibration, wear and other reasons under working conditions. The damaged surface of the badly damaged bearing shell reaches 1/3 of the total area of the bearing shell, and the bearing shell and the bearing shell peel off locally. Therefore, it was decided to use oxygen welding to repair the damaged babbitt bearing bush. 1、 1. Requirements for welding repair of bearing bush
There shall be no air hole, slag inclusion or lack of fusion in the repaired weld bead.
2. The appearance of weld bead shall be restored to the original size after repair.
2、 Preparation before welding
1. Preparation of welding wire
The bearing bush is made of Babbitt alloy ZchSnSb11-6, which is a soft metal with a very low melting point (240 ℃). The welding wire selected is the same as the bearing bush material. As shown in Figure 2, after the welding wire is melted, use a knife to remove the edges and corners, and remove the oxide film and slag holes on the surface. Do not use sandpaper or grinding wheel to dispose the surface of the welding wire.
2. Treatment of bearing bush surface
The oil molecules have penetrated into the engine body. For the bearing bush temporarily under the working condition of lubricating oil. During welding repair, these oil leaking outer layers hinder the fusion between metals, so they should be carefully cleaned.
The damaged bearing bush shall be carefully inspected to determine the welding repair position, and the bearing bush shall be put into the drying oven and heated to 150-180 ℃. After completely removing the unmelted but overheated parts on the bearing bush, carefully clean the oxide film and oil stain on its surface with commercial metal cleaner. After that, use a knife to scrape 0.2-0.5mm away from the part to be repaired. The treated bearing bush shall be welded and repaired immediately.
3、 Welding repair process of bearing bush
1. Preheating
If the temperature drops too much bearing alloy, the welding torch model is H01-61 nozzle. After the surface of bearing bush is disposed. It should be heated to 150-180 ℃ and placed on the electric furnace to slow down its cooling rate during welding repair. At this time, care should be taken to avoid re contamination of the treated bearing surface.
2. Welding repair process parameters
The welding speed is 58cm/min, the width of the primary weld bead is 810mm, the thickness is 34mm, and 2-3 layers are welded. The gas welding pressure is 0.02MPa neutral flame. The interpass temperature is greater than 150 ℃. After partial cleaning of bearing shell dew, braze the bottom layer first.
