Sandblasting, also known as shot blasting, is a common surface treatment process for workpieces. It uses compressed air as the power to spray materials (common such as copper ore, quartz sand, emery, etc.) through a high-speed jet beam. Iron sand, sea sand, etc.) are sprayed onto the surface of the workpiece at high speed. During this period, the abrasive has an impact and cutting action on the surface of the workpiece, causing the outer surface or shape of the workpiece to change, and a certain degree of roughness and cleanliness can be obtained. In addition, the sandblasting treatment also improves the fatigue resistance and mechanical properties of the workpiece, and to a certain extent also increases the bonding force between it and the coating, which effectively improves the durability of the coating and is conducive to the leveling and decoration of the coating. . At present, sandblasting is mainly used for mechanical descaling and polishing.
The equipment used in sandblasting treatment mainly includes suction dry sandblasting machine, press-in dry sandblasting machine or liquid sandblasting machine. Regardless of the type of sandblasting equipment, tungsten carbide nozzles are one of the indispensable parts. Compared with nozzles made of other materials, such as steel nozzles, tungsten carbide nozzles have higher hardness, strength, and wear and corrosion resistance. However, there are two problems when sand blasting nozzles work. One is difficulty in absorbing sand due to the poor wet sand inlet vacuum of the nozzle and the too small diameter of the wet sand inlet during sand absorbing; the other is the internal spray hole and The nozzle wear problem caused by the improper inlet distance of the sand-water mixing straight pipe section or the inappropriate material of the sand-water mixing straight pipe. Therefore, the main criteria for judging tungsten carbide sandblasting nozzles include factors such as material selection, diameter length, diameter of the sand suction pipe, and the distance between the diameter of the spray hole and the straight pipe section of the sand-water mixture. In addition, in the sandblasting process, attention should be paid to controlling the distance between the nozzle and the workpiece and the control of the position and time of the weld to eliminate the residual stress on the surface of the weld. It is also possible to add corrosion inhibitor mixed water during the sandblasting process to protect the surface of the metal workpiece after sandblasting from secondary oxidation.
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