Abstract: High-speed machining is an important trend in the development of the manufacturing industry. High-speed machining caused by high-speed machining has become a key technology in advanced manufacturing processes. Based on the development of current tool materials, the requirements of various fields are still not met. This paper analyzes the matching problem between tool materials and workpiece materials in high-speed cutting, introduces the position of tools in high-speed cutting, the requirements of high-speed cutting for tool materials, and There are types of high-speed cutting tool materials, and the matching of tool materials and workpiece materials in high-speed cutting is analyzed, and how to select high-speed cutting tool materials is explained.
0 Preface
The general trend in the development of machining is high efficiency, high precision, high flexibility and environmental awareness. In the field of machining, cutting (grinding) is the most widely used processing method. High-speed cutting is the development direction of cutting and has become the mainstream of cutting. It is an important common key technology for advanced manufacturing technology. The promotion of high-speed cutting technology will greatly increase production efficiency and processing quality and reduce costs. The development and application of high-speed cutting technology is determined by advances in machine tools and tooling technology, where advances in tool materials play a decisive role. Studies have shown that at high speed cutting, as the cutting speed increases, the cutting force decreases, and the cutting temperature rises very high. After reaching a certain value, the rise gradually slows down. The main cause of tool damage is mechanical friction, bonding, chemical wear, chipping, crushing and plastic deformation under the action of cutting force and cutting temperature. Therefore, the most important requirement for high-speed cutting tool materials is high temperature. Mechanical properties, thermophysical properties, anti-blocking properties, chemical stability (oxidation, diffusivity, solubility, etc.) and thermal shock resistance as well as resistance to coating cracking. Based on this requirement, in the past 20 years, a number of tool materials suitable for high-speed cutting have been developed, and various workpiece materials can be machined under different cutting conditions.
Although we always hope to obtain high hardness to ensure the wear resistance of the tool and high toughness to prevent cracking of the tool, the current technological development has not found such a superior performance tool material, fish in the bear's paw Can't have both. Therefore, we will select a more suitable tool material in practice according to the need: priority is given to the toughness of the tool material during roughing: the hardness of the tool material is prioritized during finishing. Of course, people are also looking forward to processing at ultra-high cutting speeds for better results. The following is a brief introduction to the common workpiece materials and related conditions of the tool.
1 aluminum alloy
1.1 Free cutting aluminum alloy
The material is widely used in the aerospace industry. The applicable knife has K10, K20 and PCD, the cutting speed is 2000~4000m/min, the feed rate is 3~12m/min, and the tool rake angle is 12°~18°. The angle is from 10° to 18° and the edge angle is up to 25°.
1.2 cast aluminum alloy
Casting aluminum alloys vary according to their Si content. K10 and Si3N4 tools can be used for cast aluminum alloys with Si content less than 12%. When Si content is greater than 12%, PKD (synthetic diamond) and PCD can be used. (Polycrystalline diamond) and CVD diamond coated tools. For silicon-on-silicon alloys with a Si content of 16% to 18%, PCD or CVD diamond coated tools are preferred, with a cutting speed of 1100 m/min and a feed rate of 0.125 mm/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 influence on the selection of the tool. When the cutting speed is lower than 750m/min, coated hard alloy and cermet can be used: Si3N4 ceramic cutter can be used when cutting speed is 510~2000m/min; CBN can be used when cutting speed is 2000~4500m/min Tool. The metallographic structure of the casting has a certain influence on the selection of high-speed cutting tools. When the cutting speed is more than 500m/min, the castings with pearlite can use CBN or Si3N4. When ferrite is mainly used, due to diffusion wear The reason for the serious wear of the tool is that CBN should not be used, but ceramic tools should be used. If the binder phase is metal Co, the grain size is 3 μm on average, and the BZN6000 with CBN content greater than 90% to 95% is suitable for processing gray cast iron with high ferrite content at V=700 m/min. The binder phase is ceramic (AlN+AlB2), Amborite insert with an average grain size of 10 μm and a CBN content of 90% to 95%. When the high pearlite content of gray cast iron is processed, when the cutting speed is less than 1100 m/min, As the cutting speed increases, the tool life also increases.
3 ordinary steel
The cutting speed has a great influence on the surface quality of steel. According to research, the optimum cutting speed is 500-800 m/min. At present, coated cemented carbide, cermet, non-ceramic, CBN tools can be used as tool materials for high-speed cutting of steel. Among them, the coated cemented carbide can be used as a cutting fluid. 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 and achieve high precision and surface quality of the machined parts. . The cermet tool currently has a large market share. The cermet with TiC-Ni-Mo as the base has good chemical stability, but has poor flexural strength and thermal conductivity, and is suitable for small feed rates of cutting speeds of 400-800 m/min. Finishing with small depth of cut: TiCN is used as the matrix, and the cermet with less molybdenum and more tungsten in the binder combines strength and wear resistance. TiN is used to increase the toughness of the cermet. The depth of cut of the processed steel or cast iron can be Up to 2 ~ 3mm.
4 high hardness steel
High-speed cutting tools for high-hardness steel (HRC40-70) are available in cermet, ceramic, TiC coated carbide, PCBN, etc. The cermet can be made of TiN-added cermet with basic composition of TiC. Its hardness and fracture toughness are roughly equivalent to those of cemented carbide, and the thermal conductivity is less than 1/1O of cemented carbide, and it has excellent oxidation resistance and adhesion resistance. And wear resistance. In addition, it has good mechanical properties at high temperatures and low affinity with steel, and is suitable for SKD processing of medium and high speed (around 200m/min). Cermets are especially suitable for grooving. The ceramic tool can cut workpiece materials with a hardness of 63HRC, such as quenching the workpiece and then cutting it to achieve “cutting and grindingâ€. When cutting 45 steel with quenching hardness of 48 ~ 58HRC, the cutting speed can be 150 ~ 18Om / min, the feed rate is O.3 ~ 0.4min / r, the cutting depth can be 2 ~ 4mm. Al203-TiC ceramic tools with a particle size of 1μm and a TiC content of 20% to 30% can be used to process high-hardness steels with high anti-flaking properties at a cutting speed of about 100m/min. When the cutting speed is higher than 1000m/min, PCBN is the best tool material, and the PCBN tool with CBN content greater than 90% is suitable for processing hardened tool steel (such as 55HRC H13 tool steel).
5 high temperature nickel base alloy
Inconel 718 nickel-based alloy is a typical hard-to-machine material with high high-temperature strength, dynamic shear strength, small thermal diffusivity, and work hardening during cutting, which leads to high temperature and wear speed in the cutting area of ​​the tool. When cutting the alloy at high speed, ceramic and CBN tools are mainly used. Silicon carbide whisker reinforced alumina ceramics can achieve long tool life at 100-300 m/min. When the cutting speed is higher than 500 m / min, the TiC alumina ceramic tool is less worn, and at 100-300 m/min. The gap wear is large. Silicon nitride ceramics (Si3N4) can also be used in the processing of Inconel 718 alloys. It is generally believed that the optimum cutting conditions for SiC whisker reinforced ceramic processing Inconel 718 are: cutting speed 700m/min, depth of cut 1~2mm, feed rate O.1~0.18mm/z. Sialon ceramics have high toughness and are suitable for cutting in solution treated Inconel 718 (45HRC) alloy. Al203-SiC whisker reinforced ceramic is suitable for processing nickel base alloy with low hardness.
6 titanium alloy (Ti6Al6V2Sn)
Titanium alloy has high strength and impact toughness, and its hardness is slightly lower than that of Inconel 718. However, its work hardening is very serious, so the phenomenon of high temperature and serious tool wear occurs during cutting. The experiment shows that the high-speed milling of titanium alloy with a 10mm diameter carbide K10 two-blade spiral milling cutter (spiral angle of 30°) can achieve satisfactory tool life, cutting speed can be as high as 628m/min, and the feed per tooth can be obtained. O.06～0.12mm/z, the cutting speed of continuous high-speed turning titanium alloy should not exceed 200m/min.
7 composite materials
Advanced composite materials for aerospace use. In the past, hard alloys and PCDs were used. The cutting speed of cemented carbide was limited. At high temperatures above 900 °C, the PCD inserts were welded to the hard alloy or high-speed steel body, and the ceramic tools were used. High-speed cutting of around 300m/min can be achieved.
High-speed cutting technology has become the mainstream of cutting processing, and speeding up its promotion and application will create huge economic benefits. High-speed cutting tool materials play a decisive role in the development and application of high-speed cutting technology. Four types of high-speed cutting tool materials, such as superhard tool materials (PCD and CBN), ceramic tools, TiC (N)-based carbide tools (cermets) and coated tools, each have their own characteristics and application range. Competing with each other to promote the development and application of high-speed cutting technology.
0 Preface
The general trend in the development of machining is high efficiency, high precision, high flexibility and environmental awareness. In the field of machining, cutting (grinding) is the most widely used processing method. High-speed cutting is the development direction of cutting and has become the mainstream of cutting. It is an important common key technology for advanced manufacturing technology. The promotion of high-speed cutting technology will greatly increase production efficiency and processing quality and reduce costs. The development and application of high-speed cutting technology is determined by advances in machine tools and tooling technology, where advances in tool materials play a decisive role. Studies have shown that at high speed cutting, as the cutting speed increases, the cutting force decreases, and the cutting temperature rises very high. After reaching a certain value, the rise gradually slows down. The main cause of tool damage is mechanical friction, bonding, chemical wear, chipping, crushing and plastic deformation under the action of cutting force and cutting temperature. Therefore, the most important requirement for high-speed cutting tool materials is high temperature. Mechanical properties, thermophysical properties, anti-blocking properties, chemical stability (oxidation, diffusivity, solubility, etc.) and thermal shock resistance as well as resistance to coating cracking. Based on this requirement, in the past 20 years, a number of tool materials suitable for high-speed cutting have been developed, and various workpiece materials can be machined under different cutting conditions.
Although we always hope to obtain high hardness to ensure the wear resistance of the tool and high toughness to prevent cracking of the tool, the current technological development has not found such a superior performance tool material, fish in the bear's paw Can't have both. Therefore, we will select a more suitable tool material in practice according to the need: priority is given to the toughness of the tool material during roughing: the hardness of the tool material is prioritized during finishing. Of course, people are also looking forward to processing at ultra-high cutting speeds for better results. The following is a brief introduction to the common workpiece materials and related conditions of the tool.
1 aluminum alloy
1.1 Free cutting aluminum alloy
The material is widely used in the aerospace industry. The applicable knife has K10, K20 and PCD, the cutting speed is 2000~4000m/min, the feed rate is 3~12m/min, and the tool rake angle is 12°~18°. The angle is from 10° to 18° and the edge angle is up to 25°.
1.2 cast aluminum alloy
Casting aluminum alloys vary according to their Si content. K10 and Si3N4 tools can be used for cast aluminum alloys with Si content less than 12%. When Si content is greater than 12%, PKD (synthetic diamond) and PCD can be used. (Polycrystalline diamond) and CVD diamond coated tools. For silicon-on-silicon alloys with a Si content of 16% to 18%, PCD or CVD diamond coated tools are preferred, with a cutting speed of 1100 m/min and a feed rate of 0.125 mm/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 influence on the selection of the tool. When the cutting speed is lower than 750m/min, coated hard alloy and cermet can be used: Si3N4 ceramic cutter can be used when cutting speed is 510~2000m/min; CBN can be used when cutting speed is 2000~4500m/min Tool. The metallographic structure of the casting has a certain influence on the selection of high-speed cutting tools. When the cutting speed is more than 500m/min, the castings with pearlite can use CBN or Si3N4. When ferrite is mainly used, due to diffusion wear The reason for the serious wear of the tool is that CBN should not be used, but ceramic tools should be used. If the binder phase is metal Co, the grain size is 3 μm on average, and the BZN6000 with CBN content greater than 90% to 95% is suitable for processing gray cast iron with high ferrite content at V=700 m/min. The binder phase is ceramic (AlN+AlB2), Amborite insert with an average grain size of 10 μm and a CBN content of 90% to 95%. When the high pearlite content of gray cast iron is processed, when the cutting speed is less than 1100 m/min, As the cutting speed increases, the tool life also increases.
3 ordinary steel
The cutting speed has a great influence on the surface quality of steel. According to research, the optimum cutting speed is 500-800 m/min. At present, coated cemented carbide, cermet, non-ceramic, CBN tools can be used as tool materials for high-speed cutting of steel. Among them, the coated cemented carbide can be used as a cutting fluid. 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 and achieve high precision and surface quality of the machined parts. . The cermet tool currently has a large market share. The cermet with TiC-Ni-Mo as the base has good chemical stability, but has poor flexural strength and thermal conductivity, and is suitable for small feed rates of cutting speeds of 400-800 m/min. Finishing with small depth of cut: TiCN is used as the matrix, and the cermet with less molybdenum and more tungsten in the binder combines strength and wear resistance. TiN is used to increase the toughness of the cermet. The depth of cut of the processed steel or cast iron can be Up to 2 ~ 3mm.
4 high hardness steel
High-speed cutting tools for high-hardness steel (HRC40-70) are available in cermet, ceramic, TiC coated carbide, PCBN, etc. The cermet can be made of TiN-added cermet with basic composition of TiC. Its hardness and fracture toughness are roughly equivalent to those of cemented carbide, and the thermal conductivity is less than 1/1O of cemented carbide, and it has excellent oxidation resistance and adhesion resistance. And wear resistance. In addition, it has good mechanical properties at high temperatures and low affinity with steel, and is suitable for SKD processing of medium and high speed (around 200m/min). Cermets are especially suitable for grooving. The ceramic tool can cut workpiece materials with a hardness of 63HRC, such as quenching the workpiece and then cutting it to achieve “cutting and grindingâ€. When cutting 45 steel with quenching hardness of 48 ~ 58HRC, the cutting speed can be 150 ~ 18Om / min, the feed rate is O.3 ~ 0.4min / r, the cutting depth can be 2 ~ 4mm. Al203-TiC ceramic tools with a particle size of 1μm and a TiC content of 20% to 30% can be used to process high-hardness steels with high anti-flaking properties at a cutting speed of about 100m/min. When the cutting speed is higher than 1000m/min, PCBN is the best tool material, and the PCBN tool with CBN content greater than 90% is suitable for processing hardened tool steel (such as 55HRC H13 tool steel).
5 high temperature nickel base alloy
Inconel 718 nickel-based alloy is a typical hard-to-machine material with high high-temperature strength, dynamic shear strength, small thermal diffusivity, and work hardening during cutting, which leads to high temperature and wear speed in the cutting area of ​​the tool. When cutting the alloy at high speed, ceramic and CBN tools are mainly used. Silicon carbide whisker reinforced alumina ceramics can achieve long tool life at 100-300 m/min. When the cutting speed is higher than 500 m / min, the TiC alumina ceramic tool is less worn, and at 100-300 m/min. The gap wear is large. Silicon nitride ceramics (Si3N4) can also be used in the processing of Inconel 718 alloys. It is generally believed that the optimum cutting conditions for SiC whisker reinforced ceramic processing Inconel 718 are: cutting speed 700m/min, depth of cut 1~2mm, feed rate O.1~0.18mm/z. Sialon ceramics have high toughness and are suitable for cutting in solution treated Inconel 718 (45HRC) alloy. Al203-SiC whisker reinforced ceramic is suitable for processing nickel base alloy with low hardness.
6 titanium alloy (Ti6Al6V2Sn)
Titanium alloy has high strength and impact toughness, and its hardness is slightly lower than that of Inconel 718. However, its work hardening is very serious, so the phenomenon of high temperature and serious tool wear occurs during cutting. The experiment shows that the high-speed milling of titanium alloy with a 10mm diameter carbide K10 two-blade spiral milling cutter (spiral angle of 30°) can achieve satisfactory tool life, cutting speed can be as high as 628m/min, and the feed per tooth can be obtained. O.06～0.12mm/z, the cutting speed of continuous high-speed turning titanium alloy should not exceed 200m/min.
7 composite materials
Advanced composite materials for aerospace use. In the past, hard alloys and PCDs were used. The cutting speed of cemented carbide was limited. At high temperatures above 900 °C, the PCD inserts were welded to the hard alloy or high-speed steel body, and the ceramic tools were used. High-speed cutting of around 300m/min can be achieved.
High-speed cutting technology has become the mainstream of cutting processing, and speeding up its promotion and application will create huge economic benefits. High-speed cutting tool materials play a decisive role in the development and application of high-speed cutting technology. Four types of high-speed cutting tool materials, such as superhard tool materials (PCD and CBN), ceramic tools, TiC (N)-based carbide tools (cermets) and coated tools, each have their own characteristics and application range. Competing with each other to promote the development and application of high-speed cutting technology.
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