Pay attention to the suitability of choosing ppe

Currently in the cutting process, commonly used tool materials are high-speed steel, carbide, ceramics and super-hard tool materials, including superhard material tools, including synthetic diamond (PCD), cubic boron nitride (CBN) and so on.

1, high-speed steel

High-speed steel (HSS) is a high-alloy tool steel that incorporates tungsten, molybdenum, chromium, vanadium, and other alloying elements. Hardness after heat treatment is 62-67HRC. It is not possible to cut hardened steel and hard cast iron with high hardness. In terms of heat resistance, it is only able to withstand cutting temperatures of up to 550-600°C, so high-speed cutting cannot be performed. However, high-speed steel has better performance in terms of strength, toughness, hot hardness and processability, and its bending strength is 5-6 times that of cemented carbide 2-3 ceramic materials.

2. Hard alloy

Carbide is made by powder metallurgy method, high hardness HRA89-93, can withstand 850-1000 °C high temperature, cutting speed up to 100-300m/min, wear resistance is several times or even several times high speed steel , Tool bending strength, impact toughness, processability than high-speed steel. More than 90% of the tools in developed countries and more than 55% of milling cutters are made of hard alloy materials, and the proportion of their use is still increasing. Cemented carbide is also used to make complex tools such as drills, milling cutters, gear cutters, and reamers. Carbide alloys are replacing other tool materials with more excellent properties and have become one of the major tool materials. At present, carbide cutting tools have occupied the leading position in the world, accounting for 70%.

3, ceramics

Ceramics is a cutting tool material that made a breakthrough in the 1980s. Compared with cemented carbide, ceramic materials have higher hardness, red hardness and wear resistance. When machining steel, the durability of ceramic tools is 10-20 times that of cemented carbide tools. Its red hardness is 2-6 times higher than cemented carbide, and its chemical stability and oxidation resistance are superior to those of cemented carbide. However, the biggest weakness of ceramics is low bending strength and poor impact toughness. Therefore, it is mainly used for the finishing of steel, cast iron, and non-ferrous metals.

4, synthetic diamond

Polycrystalline diamond (PCD), which is a homogeneous mixture of diamond fine powder and metal binder, sintered at high temperature and high pressure; it has high hardness and thermal conductivity, low thermal expansion coefficient, high elastic modulus and low The coefficient of friction is very sharp. Due to the affinity of carbon on iron, especially at high temperatures, diamond can react chemically with iron. Therefore, diamond tools are not suitable for cutting iron and its alloy workpieces. It is an ideal tool material for high-speed cutting aluminum alloys, and its cutting speed. It can reach 2500-5000m/min.

5, cubic boron nitride

Cubic Boron Nitride (CBN) is a superhard material that was synthesized in the late 1950s using a method similar to diamond manufacturing. Due to poor sintering properties of CBN, polycrystalline cubic boron nitride PCBN was made in the 1970s. CBN is a dense phase of boron nitride, with high hardness (second only to diamond) and heat resistance (1300°C, 1500°C). The cutting speed is 4-6 times that of cemented carbide tools, and it has excellent chemical stability. *** (far better than diamond) and thermal conductivity, low coefficient of friction. The affinity between PCBN and Fe elements is very low, so it is an ideal tool material for high-speed cutting of ferrous metals.