Introduction to the requirements of stainless steel shot processing on cutting tools

When machining stainless steel shot, the tool should generally consider the choice of front angle and back angle for cutting local geometric shape. When selecting the front angle, it is necessary to consider such factors as the chip rolling groove type, whether there is chamfer, and the positive and negative angle size of the blade inclination angle. No matter what kind of tool, large rake angle is used when processing stainless steel. The rake angle of the tool can reduce the resistance encountered during chip separation and removal. The requirements for back angle selection are not very strict, but should not be too small. If the back angle is too small, it will easily cause serious friction with the surface of the workpiece, which will deteriorate the surface roughness of the machining surface and accelerate tool wear. And because of the intense friction, the work hardening effect of the stainless steel surface is strengthened; The back angle of the tool should not be too large, which will reduce the wedge angle of the tool, reduce the strength of the cutting edge and accelerate the wear of the tool. In general, the back corner should be larger than when machining ordinary carbon steel. Improving the surface brightness of the cutting part of the tool can reduce the resistance when the chip forms curl, and improve the tool durability. Compared with machining ordinary carbon steel, cutting parameters should be properly reduced to reduce tool wear when machining stainless steel; At the same time, it is necessary to select proper cooling and smoothing fluid to reduce the cutting heat and cutting force in the cutting process and extend the service life of the tool. When machining stainless steel shot, due to the large cutting force, the cutter bar has sufficient strength and rigidity to avoid chatter and deformation during cutting. Therefore, it is required to select the appropriate large section area of the cutter bar, and at the same time, the materials with high strength should be used to manufacture the cutter bar, such as 45 # steel or 50 # steel treated by quenching and tempering. When machining stainless steel, it is required that the data of the cutting part of the tool have high wear resistance and can adhere to its cutting performance at a higher temperature. At present, the commonly used data are: high-speed steel and hard alloy. Because high-speed steel can only adhere to its cutting performance below 600 ° C, it is not suitable for high-speed cutting, but only suitable for processing stainless steel at low speed. Because cemented carbide has better heat resistance and wear resistance than high-speed steel, tools made of cemented carbide materials are more suitable for cutting stainless steel. Cemented carbide can be divided into two categories: tungsten cobalt alloy (YG) and tungsten cobalt titanium alloy (YT). Tungsten cobalt alloys have good toughness. The tool made can use a large rake angle and a sharp edge. During the stainless steel shot cutting process, the chip is easy to deform, the cutting is light and fast, and the chip is not easy to stick to the tool. Therefore, under normal conditions, it is more appropriate to use tungsten cobalt alloys to process stainless steel. In particular, tungsten cobalt alloy blades should be used under the conditions of rough machining and intermittent cutting of vibration. They are not as hard and brittle as tungsten cobalt titanium alloys, and are not easy to be sharpened and broken. Tungsten cobalt titanium alloy has good red hardness, and stainless steel shot is more wear-resistant than tungsten cobalt alloy at high temperature, but it is brittle and not resistant to impact and vibration. It is commonly used as stainless steel fine turning tool.