Thermal spray repair process

       (1) Cleaning: Use diesel oil, gasoline or acetone to clean the surface of the guide rail of the machine tool to remove the oil stains on the surface.



     (2) Baking and degreasing: Since the guide rail of the machine tool is a cast iron piece, some oil will penetrate into the base during use, so the oil that penetrates into the workpiece must be baked out. When baking, use a micro-carbonization flame to slowly heat up the substrate to about 300 °C

     (3) Reshaping of the sprayed part: widen the strained part with an angular grinding wheel and make it into a transition arc, especially the two ends are machined to an inclination of about 45 degrees with a chisel, and the depth of the processing groove is 0.8mm~1.2mm. .

     (4) Further clean the parts to be sprayed with acetone.

     (5) Roughen the sprayed surface; use a nickel brush to roughen the sprayed surface, remove the floating objects with a wire brush, and clean with acetone.

     (6) Spray Ni/AI bottom layer; use SPH-2000E spray gun to spray Ni/AI powder, and its spraying process parameters; oxygen pressure 0.55MPa, acetylene pressure 0.08MPa, powder feeding 0.2m3/h, spraying distance 180mm, powder feeding The weight is 40g/min, and the thickness of the bottom layer is 0.1mm. Use a wire brush to remove dust after spraying.

     (7) Spray 2CrB working layer: use SQX-1 medium speed air spray gun to spray 2CrB wire, the spraying process parameters are: oxygen pressure 0.45MPa, acetylene pressure 0.095MPa, air pressure 0.5MPa~0.6MPa, spraying distance 150mm. In the spraying process, intermittent spraying is used, and a machining allowance of about 0.6mm is left at the end.

     (8) Coating processing: The coating processing is carried out on the guide rail grinding machine in the workshop. Because the alumina bowl-shaped grinding wheel is used for dry grinding, the grinding feed must be strictly controlled to prevent the coating from falling off due to local overheating during the heating process. The grinding parameters are: the feed rate during rough grinding is 0.02mm~0.04mm, the feed rate during rough grinding is 0.005mm~0.01mm, the moving speed of the guide rail is 3m/min~5m/min, and the speed of the grinding head is 2800r/ min.

      Large-scale machine tool guide rails such as C650, B2152, T68, T6112 have been repaired by oxygen-acetylene spraying process. The use results for more than one year show that the guide rails repaired by this spraying process not only did not have the phenomenon of coating peeling, but also slowed down the occurrence of the phenomenon of strain on the guide rails of the machine tool. Effectively improve the service life of the guide rail. Therefore, the use of oxygen-acetylene spraying process to repair the machine tool guide rail is a fast, economical and reliable process method, which is currently being promoted.