▎ 摘　　要

NOVELTY - Preparation of ring-net movable contact involves mixing electrolytic chromium copper powder, introducing argon gas for 30 minutes, adding graphene powder, mixing, press-molding, sintering for 2-3 hours, discharging, cooling to room temperature, heating at 700-800 degrees C, performing hot isostatic pressing, cooling, obtaining copper-chromium alloy contact material, mechanically processing, adding a weld filler, drying, performing argon-tungsten-arc welding using a tungsten-copper alloy covering layer and cooling. USE - Preparation of ring-net movable contact (claimed). ADVANTAGE - The method enables efficient preparation of ring-net movable contact by simple and economical process. The movable contact has uniform microstructure, and has high strength, density and hardness, and excellent electroconductivity, high-temperature resistance, wear resistance, thermal conductivity and arc ablation resistance. DETAILED DESCRIPTION - Preparation of ring-net movable contact involves mixing electrolytic chromium having grain diameter of 20-30 mu m and copper powder in mass ratio of 3:2-3, introducing argon gas for 30 minutes, adding 0.5-0.8 %mass graphene powder having grain diameter of 20-30 mu m, mixing uniformly, press-molding at 400-600 MPa and 1000-1050 degrees C in a vacuum environment, sintering for 2-3 hours, discharging, cooling to room temperature, heating at 700-800 degrees C for 0.5-1 hour under vacuum degree of 1x 10-4 Pa, performing hot isostatic pressing, heating to 950-1050 degrees C for 2-3 hours, cooling, obtaining copper-chromium alloy contact material, mechanically processing to rectangular parallelepiped shape with an equally spaced groove, further mechanically processing to a cylindrical shape, performing argon arc welding, adding a weld filler, drying, calibration argon-tungsten arc welding gun and powder feeding mechanism feeding nozzle, performing argon-tungsten-arc welding using a tungsten-copper alloy covering layer, naturally cooling, detecting the resultant product with ultrasonic automatic detecting device. The tungsten-copper alloy covering layer of contact material is obtained by placing mixed metal powder in a mold, press-molding, and sintering at 1200-1300 degrees C for 60-120 minutes, cooling to the room temperature. The mixed metal powder is obtained by mixing electrolytic copper powder having average particle size of 4-10 mu m, and tungsten powder in a powder mixer, and comprises 28-42 %mass copper powder and remainder of tungsten powder.