Cemented carbide can be divided into tungsten cobalt alloy (YG) and tungsten cobalt titanium alloy (YT). Tungsten cobalt alloy has good toughness. The tool made of tungsten cobalt alloy can use a larger rake angle and edge to grind out a sharper edge. In the cutting process, the chip is easy to deform, cutting is light, and the chip is not easy to stick to the tool. Therefore, in general, it is more appropriate to use tungsten cobalt alloy to process stainless steel. Especially in rough machining and intermittent machining with large vibration, tungsten cobalt alloy blade should be used. It is not as hard and brittle as tungsten cobalt titanium alloy, and is not easy to grind and break. W-co-ti alloy has better red hardness and is more wear-resistant than W-Co alloy at high temperature, but it is more brittle and not resistant to impact and vibration. It is generally used as stainless steel precision turning tool.
When machining stainless steel according to the requirements of tool geometric parameters, the geometric shape of the cutting part of the tool should be considered from the selection of front angle and back angle. When selecting the rake angle, the factors such as chip curling groove type, chamfering and the positive and negative angle of the blade angle should be considered. No matter what kind of tool, the larger rake angle must be used when machining stainless steel. Increasing the rake angle of the tool can reduce the resistance in the process of chip separation and cleaning. It is not very strict to select the back angle, but it should not be too small. If the back angle is too small, it is easy to cause serious friction with the workpiece surface, which will worsen the surface roughness and accelerate the tool wear. And because of the strong friction, it enhances the effect of stainless steel surface work hardening; the tool back angle should not be too large, too large back angle will reduce the wedge angle of the tool, reduce the strength of the cutting edge, and accelerate the wear of the tool. Generally, the back angle should be larger than that of ordinary carbon steel.
In order to meet the requirements of surface roughness of cutting part, improving the surface finish of cutting part can reduce the resistance of chip curling and improve the tool life. When machining stainless steel, the cutting parameters should be reduced to slow down the tool wear, and the appropriate cooling and lubricating fluid should be selected to reduce the cutting heat and cutting force and prolong the service life of the tool.
When machining stainless steel according to the requirements of cutter bar material, the cutter bar must have enough strength and rigidity to avoid chatter and deformation in the cutting process due to the large cutting force. This requires the selection of appropriate large cross-sectional area of the cutter bar, and the use of high-strength materials to manufacture the cutter bar, such as 45 steel or 50 steel with quenching and tempering treatment.
When machining stainless steel, it is required that the cutting material of the tool should have high wear resistance and keep its cutting performance at high temperature. At present, the commonly used materials are: high speed steel and cemented carbide. Because high speed steel can only maintain 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, the tool made of cemented carbide is more suitable for stainless steel cutting.