1. Severe work hardening The work hardening of stainless steel is very serious.
The first choice is a mixture of austenite and ferrite. The hardness of the hardened layer is 1.4-2.2 times that of the original matrix, and the strength is R=1470-1960MPa. This stainless steel has great plasticity and a large strengthening coefficient. In addition, austenite is unstable and easily transformed into martensite under the action of cutting force.
2. Large cutting force Stainless steel has high plasticity, especially austenitic stainless steel, which is 2.5 times deeper than 45# steel. The milling machine has large plastic deformation, large cutting resistance, severe work hardening, high thermal strength, and is not easy to curl and break.
3. High cutting temperature Stainless steel has large plastic deformation, large friction, and relatively low thermal conductivity. Therefore, under the same conditions, the temperature of the stainless steel milling machine is about 200 degrees higher than that of 45 steel.
4. Cutting is not easy It is easy to bond and form built-up edge when processing stainless steel. The plasticity and toughness of stainless steel are relatively large, and it is not easy to be damaged by the milling machine. Under high temperature and high pressure, the tool is prone to adhesive wear and edge accumulation.
5. The tool is easy to wear Of course, stainless steel milling cutters should be used to process stainless steel, because the TiC hard spots in stainless steel will cause severe grinding and wear of the tool. Under high speed, high temperature and high pressure conditions, the tool and the tool are prone to adhesion, diffusion and crescent wear.
What kind of milling cutter is used for stainless steel processing?
When processing stainless steel, it is best to choose materials with high hardness, wear resistance, strength and toughness, and good thermal conductivity. Carbide materials: YG, YW, etc. Use tungsten cobalt fine or ultrafine cemented carbide containing TaC or NbC. YG6x, YG813, YW4, YD15, etc. High-speed steel materials: W6Mo5Cr4V2Al, W10Mo4CrV3Al, etc. If ordinary stainless steel materials such as 201, 304 are used for milling, please use ordinary carbide coated milling cutters and select 4 blades for appropriate milling. Secondly, all major CNC tool suppliers have dedicated stainless steel milling cutters. If customers are not sensitive to price, they can choose this type of tool. When processing 316 stainless steel, stainless steel after quenching and heat treatment, imported and high-hardness stainless steel, in addition to using high-hardness tools, the stainless steel cutting edge should be sharper. It is best to use special stainless steel tools from various well-known brands.
Reasonable cutting parameters for stainless steel processing
The processing of stainless steel can be divided into roughing and finishing. For roughing, YW and YT carbides with relatively low TiC content can be selected. For finishing, YW and YT carbides with high TiC content can be selected.
Secondly, in order to prevent the edge from chipping during stainless steel processing, the blade strength should be increased, and it is best to choose a small rake angle or a negative rake angle. When using carbide to process stainless steel, the preferred helix angle is 5-10 degrees. If a high-speed steel end mill is used, 35-45 degrees should be selected. When milling stainless steel, it is best to choose an end mill with a large helix angle. If you want to mill stainless steel pipes or thin-walled workpieces, you can choose a tapered end mill.
Commonly used stainless steel milling machine usage。
For carbide stainless steel milling, the milling machine speed should be 40~60m/min. The feed rate should be greater than 0.1mm to avoid the hardened layer edge and accelerate tool wear. High-speed steel end mill, cutting speed 8~40m/min, feed rate 0.013~0.15mm/z.
Additional knowledge for processing stainless steel It is best not to use high-speed steel end mills for machining hardened stainless steel.
If the steel is harder, choose a lower grinding amount.
If you have a lot of side cutters, choose a slow milling machine. Using coated carbide tools can increase the milling machine speed by about 50%. Be sure to let it cool completely when cutting. When using carbide tools to process stainless steel, do not use water-soluble cutting fluids to avoid excessive thermal stress and chipping of the cutting edge.
