How to choose different tools for high speed precision machining of stainless steel parts

Reasonable choice of tool material is an important condition for high efficiency machining of stainless steel. According to the cutting properties of stainless steel, the tool material is required to have good heat resistance, high wear resistance, and a small affinity with stainless steel. Currently commonly used tool materials are high speed steel and cemented carbide.

High Speed ​​Steel Selection

High speed steel is mainly used in the manufacture of complex multi-blade tools such as milling cutters, drills, taps and broaches. Regular high-speed steel W18Cr4V tools are less durable and do not meet your needs. Good results are obtained by cutting stainless steel with new high speed steel tools.

Under the same turning conditions, two types of cutting tools, W18Cr4V and 95w18Cr4V, are used to machine 1Cr17Ni2 parts. The number of parts machined at one time by tool grinding is 2-3 and 12, respectively, but the tool durability at 95w18Cr4V is improved several times. This is due to the increase in carbon content of 95w18Cr4V steel, which increases the carbide content of the steel. The hardness at room temperature is 2HRC, which is better. At 600 ° C, HRC48.5 of W18Cr4V rises to HRC51-52, and wear resistance is 2-3 times higher than that of W18Cr4V.

A surface milling cutter made of high vanadium high speed steel W12Cr4V4Mo was used to machine 1Cr17Ni2, which was able to obtain higher tool durability. Since the vanadium content is increased, high hardness VC can be formed in the steel, and fine VC is present in the crystal medium, which prevents grain growth and improves the wear resistance of the steel. Can be done. W12Cr4V4Mo has a good red hardness and hardness up to HRC 51.7 at 600 ° C, so it is suitable for making complex tools for cutting stainless steel. However, the strength (sb = 3140MPa) and impact toughness (ak = 2.5J / cm3) are slightly lower than W18Cr4V, so be careful when using it.

With the continuous development of tool manufacturing technology for large batch workpieces, the use of carbide multi-blades, complex tools for cutting results will be better.

Cemented Carbide Tool Selection

YG-based cemented carbide has good toughness, can use large rake angles, can sharpen blades to lighten cutting, it is not easy to join tips and tools, which is stainless steel Suitable for processing. This advantage of YG-based alloys is especially important for vibrating roughing and intermittent cutting. Moreover, YG alloys have good thermal conductivity, which is almost twice that of high speed steel and twice that of YT based alloys. As a result, YG alloys are widely used in machining  stainless steel, especially in the manufacture of roughing tools, cutting knives, reamer drills and reamers.

Common grades such as YG6, YG8, YG8N, YW1 and YW2 have long been used as cutting tool materials for cutting stainless steel, but they have not achieved satisfactory results. Better results can be obtained by using newer grade cemented carbides such as 813, 758, 767, 640, 712, 798, YM051, YM052, YM10, YS2T, YD15. Cutting austenitic stainless steel with 813 grade carbide tools is very effective. The 813 alloy has high hardness (≥HRA91), strength (sb = 1570MPa), excellent high temperature toughness, oxidation resistance and anti-adhesiveness, so its structure is excellent in compactness and wear resistance.

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