Classification and Selection of Cutting Tool Materials

For modern machinery manufacturing industry, cutting tools for machining play a key role in improving production efficiency and product quality, and the selection of cutting tool materials is an important part. Because the performance of the cutting tool material can affect the cutting efficiency and tool life of the machined parts surface, thus Heygo tools pay high attention to the cutting tools material.

High-performance cutting tools depend on excellent raw materials, which require the following:

(1) high hardness and wear resistance

(2) sufficient strength and toughness

(3) high heat resistance

(4) Good manufacturability

(5) Good thermal conductivity and small expansion coefficient.

Currently, cutting tool materials are mainly divided into four categories: tool steel (including carbon instrument steel, Alloy steel, and high-speed steel), hard alloy, ceramic and ultra-hard cutting tool materials. High-speed steel and hard composite steel are commonly used in machining. This article mainly introduces high-speed steel and hard alloy steel, which are also the main materials of our cutting tools.

High-speed steel

High-speed steel is a kind of tool steel with high hardness and high wear resistance, which contains many elements such as W, Mo, Cr, V, etc. High-speed steel has good comprehensive properties and is the most widely used as cutting tools material. Therefore, it is mainly used to manufacture complex thin blades and impact-resistant metal cutting tools. It can also be used to manufacture high-temperature bearings and cold extrusion dies. After heat treatment, high speed steel has a hardness of 62 ~ 62～66HRC, bending strength of about 3.3GPa and heat resistance of about 600℃. In addition, it has the advantages of small heat treatment deformation, forging and easy grinding of sharp cutting edges. It is often used to manufacture forming tools with complex structures, such as milling cutters and broaches, cutting tools etc.  According to their properties and uses, they can be divided into ordinary high-speed steel (general high-speed steel) and high-performance high-speed steel.

Common high-speed steel is the most widely used steel in cutting tool materials, accounting for more than 70% of the total consumption of high-speed steel cutting tools. According to the content of tungsten and molybdenum, it is divided into tungsten system and tungsten-molybdenum system. It is suitable for cutting speed of 25 ~ 40m/min for common steel materials. When the drill bit tip’s temperature reach 550 ~ 600℃ during the process, it can still maintain the hardness HRC60-62. It is the main material for making tools such as drill bits, machine taps, end mills, hobs, gear shapers, broaches, etc. It is also used for making cold working dies, precision stamping dies, rollers, high temperature bearings, etc, which require high wear resistance. M2 is a grade widely used at home and abroad industrial. Although its decarburization sensitivity is slightly higher, it has small and uniform carbides and high wear resistance. It is usually used to make various tools, such as twist drills, taps and reamers, same as Heygo HSS drill’s material.

High-performance cutting tool material is a category formed by adding > 2.50% v or ≥ 4.50% Co or 0.80 ~ 1.20% al to common cutting tool material and adding carbon at the same time. Hardness can reach 65-70 HRC, and with significantly improved wear resistance and heat resistance. It can be used for processing stainless steel, heat resistant steel and high strength steel.

• W6Mo5Cr4V2Co5

High-performance high-speed steel containing 5% cobalt has HRC65-67 hardness after heat treatment, excellent high hardness and good toughness. Due to its fine carbide, good machinability and heat treatment responsiveness, it is an ideal material for manufacturing cutting tools with complex shapes and high hardness. It is widely used for fully ground drill bits, machine taps, gear tools, punches, Punch, etc.  Heygo HSS-E twist drill for stainless steel adopt such material.

• W2Mo9Cr4VCo8

Containing 8% cobalt has the following main characteristics: high heat treatment hardness, high red hardness, good wear resistance, and good machining performance. It is suitable for manufacturing broaches, end mills, band saw blades, turning tools, etc.

• W6Mo5Cr4V2Al

Super hard high-speed steel, after heat treatment, it can reach HRC66-68. The main characteristics are as follows: high quenching and tempering hardness and red hardness, good machining performance, and good wear resistance. The heat treatment process of aluminum cutting tool materials is relatively strict. If the heat treatment is improper, especially the annealing after deformation processing, it is easily to happen the phenomena of crystal mixing and cutting edge breakage.

• CW6Mo5Cr4V3

High vanadium high speed steel, through a special smelting process, disperses the carbides in the steel, has excellent mechanical properties and heat treatment consistency. The even and fine VC particles ensure that the material has good wear resistance and excellent toughness, thus greatly reducing the risk of cutting edges breakage during use. It is suitable for manufacturing high quality taps, high wear resistance, high toughness and small size tools. Heygo machine taps are mainly made of high vanadium high speed steel.

Cemented carbide

Cemented carbide has a hard compound of refractory metal and an alloy material made of bonding metal through powder metallurgy industry. Cemented carbide has good heat resistance, high cutting efficiency, good strength and toughness, wear resistance, corrosion resistance and other properties. The common hard alloy contains a large amount of WC and TiC, so its hardness and heat resistance are higher than tool steel. Cemented carbide is one of the main tool materials today. Cemented carbide is widely used as tool materials such as turning tools, milling cutters, drill bits, boring cutters, etc. Heygo carbide twist bit series could compete with the imported brand tools.

Same materials, the quality of different manufacturers is not the same, the price is also very different. In China, high-end high-speed steel M2 materials can reach 11000 USD/ton and 6200 USD/ton. The difference between them depends on the raw materials, the level of heat treatment. So the purity, carbon content and carbide uniformity of high speed steel materials produced by different manufacturers are different. Heygo is choosing the best high-speed steel and cemented carbide supplier as cooperators and carry out quality monitoring on each batch of raw materials to ensure the first quality factors of cutting tools. To be a world-class cutting tools manufacturer, the raw material manufacturer has to be too.