The hottest high-performance smelting high-speed s

High performance smelting high-speed steel

high speed steel material was invented at the end of the 19th century and is generally made by smelting. Typical grades of ordinary high-speed steel are W18Cr4V and W6Mo5Cr4V2. In the modern machining with the increasing requirements of machining efficiency and machining quality, their performance is insufficient. In the late 20th century, many high-performance high-speed steels gradually appeared. On the basis of ordinary high-speed steel, high-performance high-speed steel can significantly improve its mechanical properties at room temperature and high temperature by adjusting the basic chemical composition and adding other alloy elements. The chemical composition and mechanical properties of representative high-performance high-speed steels at home and abroad are listed in the attached table, and their characteristics are described below:

1 high carbon high-speed steel

on the basis of W18Cr4V. Increase the carbon content by 0.2% to form 95w18cr4v. According to the theory of chemical equilibrium carbon, the carbon content in austenite of high-speed steel can be increased during quenching and heating, and the dispersion hardening effect during tempering can be strengthened, so as to improve the hardness at room temperature and high temperature. Compared with W18Cr4V, the wear resistance and tool durability of 95w18cr4v are improved, and the grinding performance is equivalent. Although the cutting performance of this steel is not as good as that of high cobalt and high vanadium high-speed steel, it is cheap and the cutting edge can be ground very sharp, so it has application value. Similarly, there is 100w6mo5cr4v2 (cm2) high carbon high speed steel

2 high cobalt high speed steel

adding cobalt to high speed steel can promote the precipitation of tungsten and molybdenum carbides from martensite during tempering, improve the dispersion hardening effect, and improve the thermal stability, so it can improve the hardness and wear resistance at room and high temperature. Increasing cobalt content can also improve the thermal conductivity of steel and reduce the friction coefficient between tools and workpieces. M42 is a representative steel in the United States, and its comprehensive performance is very superior. Hsp-15 in Sweden is also this kind of steel, but its vanadium content is 3%, and its grinding machinability is not as good as M42. Cobalt content is high and expensive, which is not suitable for China's national conditions. Co5si, a low cobalt silicon containing high-speed steel successfully developed in China, has superior performance and its price is lower than M42 and hsp-15. However, co5si also contains 3% vanadium and has poor grinding machinability, so it is not suitable to use it to make cutting tools with complex cutting edges

3 high vanadium high speed steel

high vanadium high speed steel (such as B201, B211, b212) has a vanadium content of 3% - 5%, while increasing the carbon content to form VC and v4c3, so that the high speed steel has high hardness and wear resistance. High vanadium high speed steel has good heat resistance, but high vanadium high speed steel has poor grinding machinability, poor thermal conductivity and low impact toughness, so it is not suitable for complex cutting tools. Appropriate cobalt can also be added to high vanadium high speed steel to become high vanadium cobalt high speed steel. The high vanadium nitrogen-containing high-speed steel v3n developed in China has low price, good cutting performance and difficult grinding. Later, a low cobalt nitrogen-containing high-speed steel co3n (w12mo3cr4vco3n) was developed, which has good cutting performance and grinding performance, but the price is higher than v3n

4 aluminized high-speed steel

China has developed a cobalt free and inexpensive aluminized high-performance high-speed steel 501. The aluminum content is about 1%. Aluminum can improve the solubility of tungsten and molybdenum in steel, resulting in solid solution strengthening. Because aluminum compounds can play a "pinning" role in steel, the hardness and wear resistance of steel at room temperature and high temperature can be improved, and the strength and toughness are also relatively high. The cutting performance is equivalent to M42. The vanadium content of 501 is 2%, and the grinding performance is a little cheaper than M42. 5f6 is also a high-performance high-speed steel containing 1% aluminum, and B201, B211 and b212 also contain aluminum. Aluminized high-speed steel is an original creation of China. 501 is widely used in China and abroad; Other aluminum containing high-speed steels are not as widely used as 501

when cutting difficult to machine materials, high-performance high-speed steels of different grades should be reasonably selected. Cutting common difficult machining materials, such as high-strength steel, austenitic stainless steel, high-temperature alloy, titanium alloy, etc., the above high-performance high-speed steel can be selected. When selecting, the mechanical properties and grinding properties of high-speed steel should be mainly considered: under the conditions of rough machining or intermittent cutting, high-performance high-speed steel with high bending strength and impact toughness should be selected; When finishing, the bending strength and impact toughness of high-speed steel are low, and its wear resistance is mainly considered at this time; When the rigidity of the process system is poor, the brand of high-speed steel is the same as that of rough machining; When the rigidity of the process system is good, the brand of high-speed steel is the same as that of finish machining; For cutting tools with complex cutting edges, low vanadium high cobalt or low vanadium aluminum containing high-speed steel with good grinding performance should be selected; High vanadium high speed steel with poor grinding performance can be selected for tools with simple blade type. Chemical composition and mechanical properties of high-performance high-speed steel

chemical composition of high-speed steel grades (%)

HRC high temperature hardness

600 ℃

HRC bending strength

GPA impact toughness

MJ/m2cwmocrvcomnsial other 95w18cr4v0.90 ~ 1.0017.5 ~ 19.0 ≤ 0.33.80 ~ 4.401.00 ~ 1.40 - ≤ 0.40 ≤ 0.40--67 ~ 68523.000.17 ~ 0.22w6mo5cr4v2al (501) 1.05～1.205.50～6.754.50～5.503.80～4.401.75～2.20-≤0.40≤0.600.30～1.～ 6954～553.50～3.800.20W12Mo3Cr4V3N (V3n)1.10～1.2511.0～12.52.50～3.503.50～4.102.50～3.10----N0.04～0.1067～70552.00～3.500.15～0.40W12Mo3Cr4V3Co5Si (Co5Si)1.20～1.3511.5～13.02.80～3.403.80～4.402.80～3.404.70～5.10≤0.400.80～1.20--59～70542.40～2.700.11W10Mo4Cr4V3Al (5F6) 1.30 ~ 1.459.00 ~ 10.503.50 ~ 4.503.80 ~ 4.502.70 ~ 3.20 - ≤ 0.50 ≤ 0.500.70 ~ 1.2, resulting in serious pollution of cotton fields in some areas ~ 69543.070.20w6mo5cr4v5sinbal (B201) 1.55 ~ 1.655.00 ~ 6.005.00 ~ 6.003.8 ~ 4.404.20 ~ 5.20 - ≤ 0.401.00 ~ 1.400.30 ~ 0.70nb0.20 ~ 0.5066 ~ 68513.600.27w6mo5cr4v5co3sinbal (B211) 1.60 ~ 1.906.005.504.005.003 00～1.401.20Nb0.35----W18Cr4V4SiNbAl (B212)1.48～1.5817.5～18.. 80～4.403.80～4.40--1.00～1.401.00～1.60Nb0.10～0.2067～69512.30～2.500.11～0.22110W1.5Mo9.5Cr4VCo8(M42)1.05～1.151.00～2.009.00～10.003.80～4.400.80～1.507.50～8.50≤0.40≤0.40--67～69552.70～3.800.23～0.30W9Mo3Cr4V3Co10 (HSP-15) 1.20 ~ 1.308.50 ~ 10.02.90 ~ 3.503.80 ~ 4.402.80 ~ 3.409.00 ~ 10.00---67 ~ 69562.350.15

the author has done comparative tests of cutting high-strength steel 36crni4mova (quenched and tempered, HRC) with a variety of high-performance high-speed steel turning tools and ordinary high-speed steel (W18Cr4V) turning tools. Tool geometric parameters; Anterior horn γ 0=4 °, main deflection angle κ R=45 °, tool tip arc radius γε= 0.2mm。 Cutting depth α P=1mm, feed rate f=0.1mm. See Figure 1 for the wear curve of some cutters. T- ν The curve is shown in Figure 2. It can be seen from the figure that the wear resistance and service life of various high-performance high-speed steel tools are much higher than W18Cr4V. V3n and co5si are particularly in the lead. 36crni4mova is a difficult to machine material, and the advantages of high-performance high-speed steel are particularly significant when cutting difficult materials

Figure 1 wear curve of turning high-strength steel with high-performance high-speed steel and ordinary high-speed steel

workpiece material: 36crni4mova

tool material: 1 Discussion on v3n in car VOC test method and improvement scheme (Wang Sufang, technical manager of Shanghai Boni Test Technology Co., Ltd.) 5Si 3 B201 4. M42 5. W18cr4v

Figure 2 T-shape of turning high-strength steel with high-performance high-speed steel and ordinary high-speed steel- ν Curve

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