Selection of cutting tool materials in the hottest

Selection of cutting tool materials in high-speed cutting 1. Introduction more than 20 years ago, high-speed cutting was mainly used for aluminum alloy processing in aerospace industry. With the continuous emergence of new cutting tool materials, people began to engage in high-speed cutting research of ordinary steel, cast iron, high-strength steel, superalloy, titanium alloy and composite materials, and continued to make new achievements

although China has no self-made high-speed cutting production equipment, some enterprises have imported a considerable number of high-speed cutting equipment, and most users are facing the problem of lack of high-speed cutting data. This paper makes a detailed summary on the selection of scattered and sporadic cutting tool materials in the literature, and expounds the classification according to the processed materials, so as to meet the needs of different users

II. The cutting tool material for high-speed cutting is

1, aluminum alloy

free cutting aluminum alloy

this material is widely used in the aerospace industry. The applicable cutting tools are K10, K20 and PCD. The cutting speed is 2000 ~ 4000m/min, the feed rate is 3 ~ 12m/min, the tool front angle is 12 ° ~ 18 °, the rear angle is 10 ° ~ 18 °, and the edge angle can reach 25 °

it does not cause continuous inflammation or toxic reaction after implantation in human body; Cast aluminum alloy

cast aluminum alloy uses different cutting tools according to its Si content. K10 and Si3N4 cutting tools can be used for cast aluminum alloy with Si content less than 12%. When Si content is greater than 12%, PKD (artificial diamond), PCD (polycrystalline diamond) and CVD diamond coated cutting tools can be used. PCD or CVD diamond coated cutting tools are best used for peraluminous alloys with a Si content of 16% - 18%, with a cutting speed of 1100m/min and a feed rate of 0.125mm/r

2, cast iron

for castings, when the cutting speed is greater than 350m/min, it is called high-speed machining, and the cutting speed has a great impact on the selection of cutting tools. When the cutting speed is lower than 750m/min, coated cemented carbide and cermet can be selected; When the cutting speed is 510 ~ 2000m/min, Si3N4 ceramic tool can be selected; When the cutting speed is 2000 ~ 4500m/min, CBN tools can be used

the metallographic structure of castings has a certain impact on the selection of high-speed cutting tools. When machining castings dominated by pearlite, CBN or Si3N4 can be used when the cutting speed is greater than 500m/min. When ferrite is dominant, the tool wear is serious due to diffusion wear, so CBN should not be used, but ceramic tools should be used. If the bonding phase is metal co, the average grain size is 3 m, and the CBN content of bzn6000 is greater than 90% - 95%, when v=700m/min, it is suitable to process gray cast iron with high ferrite content. The bonding phase is ceramic (AlN + AlB2), the average grain size is 10 m, and the CBN content is 90% - 95%. When machining gray cast iron with high pearlite content, when the cutting speed is less than 1100m/min, the tool life increases with the increase of cutting speed

3, the cutting speed of ordinary steel has a great impact on the surface quality of steel. According to the research of PTW Institute of Darmstadt University in Germany, the optimal cutting speed is 500 ~ 800m/min

at present, coated cemented carbide, cermet, non-metallic ceramics and CBN tools can be used as tool materials for high-speed cutting steel parts. Cutting fluid can be used for coating cemented carbide. The wear resistance of tin coated tools produced by PVD coating method is better than that of coated tools produced by CVD coating method, because the former can well maintain the shape of the cutting edge, so that the machined parts can obtain higher accuracy and surface quality

cermet tools account for 30% of the tool market in Japan. Cermet based on TiC Ni Mo has good chemical stability, but poor bending strength and thermal conductivity. It is suitable for finishing with small feed and small cutting depth at cutting speed of 400 ~ 800m/min; Carboly uses TiCN as the matrix and cermets with less molybdenum and more tungsten in the binder to combine strength and wear resistance. Kyocera uses tin to increase the toughness of cermets, and the cutting depth of its processed steel or cast iron can reach 2 ~ 3mm. CBN can be used to mill bearing steel or hardened steel containing trace or no ferrite structure

4, high hardness steel

high hardness steel (hrc40 ~ 70) high speed cutting tools can be used for cermets, ceramics, tic coated cemented carbide, PCBN, etc

the basic component of cermets is tic, and the cermets added with tin have roughly the same hardness and fracture toughness as cemented carbide, while the thermal conductivity is less than 1/10 of cemented carbide, and have excellent oxidation resistance, adhesion resistance and wear resistance. In addition, it has good mechanical properties at high temperature and low affinity with steel, which is suitable for SKD processing of medium and high speed (about 200m/min) die steel. Cermet is especially suitable for grooving

ceramic tools can be used to cut workpiece materials with hardness up to HRC63. If the workpiece is quenched and then cut, the "cutting instead of grinding" can be realized. When cutting 45 steel with quenching hardness of hrc48 ~ 58, the cutting speed can be 150 ~ 180m/min, the feed rate can be 0.3 ~ 0.4min/r and the cutting depth can be 2 ~ 4mm in order to reduce the vibration and noise during the operation of machine equipment and vehicles (such as trains, automobiles, aircraft and ships). Al2O3 TiC ceramic tools with particle size of 1 m and tic content of 20% - 30% can be used to process high hardness steel with high spalling resistance when the cutting speed is about 100m/min

when the cutting speed is higher than 1000m/min, PCBN is the best tool material, and PCBN tools with CBN content greater than 90% are suitable for processing hardened tool steel (for example, the manufacturer of tensile testing machine under HRC55 will talk to you about the installation process of AD card of microcomputer controlled electronic universal testing machine: H13 tool steel)

5, high temperature nickel base alloy

inconel718 nickel base alloy is a typical difficult to machine material, which has high high temperature strength, dynamic shear strength, low thermal diffusion coefficient, and is prone to work hardening during cutting, which will lead to high temperature in the cutting area of the tool and accelerated wear speed. Ceramic and CBN tools are mainly used in high-speed cutting of this alloy

it is inevitable that some electrostatic silicon carbide whiskers strengthen alumina ceramics on human body. When the cutting speed is higher than 500m/min, the tool wear of adding tic alumina ceramics is small, but it is lacking when the cutting speed is 100 ~ 300m/min