Repair of Bulldozer Drive Shaft for Bulldozing by Flame Spraying

       (1) Spraying objects. The drive shaft of the pusher is used for power transmission and is the key component of the pusher. The spraying part is the sealing ring of the transmission shaft, and the wear depth is 0.52mm. The size after spraying and repairing is required to be φ85.10～φ85.15mm, and oil leakage is not allowed, otherwise it will easily lead to burning of bearings, clutches and other components, resulting in serious mechanical failure. The base material is 35SiMnMo medium carbon alloy structural steel.



(2) Spraying process



1) Surface pretreatment. Use propane to clean the surface of the workpiece to remove oil stains; the processing size of the sprayed part is φ84~φ84.15mm, and the thread groove is opened, the thread pitch is 0.7~1mm, and the thread depth is 0.3~0.5mm.



2) Preheating. Preheat the pretreated parts to be sprayed with an oxygen-b fast flame on a lathe, and the preheating temperature is 130~150℃.



3) Spray the adhesive bottom layer. After reaching the preheating temperature, spray the nickel-clad aluminum composite powder. The thickness of the coating is controlled within the range of 0.09~0.12mm. It should not be too thick. It is advisable to cover the surface to be sprayed. The flame is neutral flame.



4) Spray the working coat. After spraying the bonding bottom layer, remove the deposits on the surface of the bonding bottom layer with a wire brush, and then quickly spray the working layer powder. The powder material can be selected from iron-based spray powder with a hardness of 300~350HBS for free cutting. The distance between the nozzle and the workpiece surface is 150~180mm. The flame is neutral flame. The temperature is controlled not to exceed 300°C. Taking into account the machining allowance, the thickness of the working layer is about 1.4mm.



5) Coating cooling and processing. The coating cooling method can be used for rotating cooling on the lathe. The coating cutting process should be carried out when the workpiece cools to room temperature. The cutting process should be very meticulous. The cutting speed should be controlled at 20~40m/min, and the feed rate during cutting should be controlled at 0.1~0.2mm/r.



(3) Effects. The main clutch drive shaft has improved wear resistance and extended service life after spraying repair, which not only has significant direct economic benefits, but also great indirect economic benefits.