The metal surfacing technology is to select the surfacing metal with high red hardness, high hardness and high wear resistance, and surfacing alloy steel with a certain thickness on the parts that are prone to fatigue deformation of the forging. Therefore, suitable electrodes should be selected according to the different requirements of forgings during surfacing welding, such as manganese-molybdenum steel, manganese-chromium-silicon and other electrodes.
Forging electroplating is the basic principle of applying electrochemistry. In the electrolyte, the forging is used as the cathode and the metal is used as the anode. Through direct current, a solid coating is deposited on the surface of the forging. Forgings should be degreased, derusted and activated before electroplating, and can be purified after plating.
Chromium plating is the most widely used surface electroplating strengthening technology for forgings. The hardness of the chrome plating layer is 900-1200HV, which can effectively improve the wear resistance of forgings and will not cause deformation of forgings. It is beneficial to the electroplating strengthening of forgings with complex shapes. -0.30mm. This process is only suitable for smaller drawing dies and plastic molds.
Pneumatic grinding wheels are used to eradicate fatigue cracks in the general parts of the repaired forgings, and arc gouging is used to eliminate the deep parts of the dead corners. After that, gas cutting can be used to process concave tables with a depth of 10mm in the repaired parts, and then the surface is cleaned. In order to prevent cracking after surfacing repair, surfacing forgings should be preheated (450-500°C), and slowly cooled after surfacing to prevent cracking, and then tempered immediately. At this time, the hardness of the surfacing part is much higher than that of the mold body.
Die surfacing technology can make forgings obtain ideal comprehensive performance, reduce remanufacturing costs and prolong service life. Generally, 5000-6000 pieces of trimming dies for forging can be scrapped, and the service life can be increased by 1-2 times after surfacing. The life of the hot forging die can be increased by more than 1 times, and it can be repaired many times.