High Speed Steel
High speed steel (HSS) is a tool steel with high hardness, high wear resistance and high heat resistance. And people also call it air hardening steel. Which can hardening when it cooling in the air during the quenching. There are two kinds of materials as its main part. Such as metal carbide and steel substrate. The metal carbide including tungsten carbide, molybdenum carbide and vanadium carbide. They will make material get better strength and wear resistance. And the steel substrate, which is distributed at the carbide around. It will influence material properties. Make it get better toughness and the ability to absorb shock and prevent chipping. The red hardness of high-speed steel is high. And has great wear resistance, good process performance. Even the strength and toughness are best during all types of steel. So it is used to make the complex blade and metal cutting tools with good impact resistant ability. And it also is great material for cold worked mold base, high-temperature springs and etc.
High Speed Steel Composition
High-speed steel is made from W, Mo, Cr, Co, V, and etc elements. And HSS is high alloy steel with high carbon content. Its carbon content is about 0.7%-1.65%. And the alloy content is about 10%-25%.
High-speed steel is widely used in all kinds of processing cutting tools. The tools usually are a large size and the environment during the work is high cutting speed, heavy load and high working temperature. It also is used to make cold and hot work mold base with the request of high wear resistance.
According to the GBT9943-2008, classify HSS under three types by material performance. For example low alloy high speed steel (HSS-L), normal high speed steel (HSS), high-performance high speed steel (HSS-E).
High Speed Steel Grade Equivalent Chart
High Speed Steel Properties and Application
It has great hot hardness. And it is easy to grinding and processing. The quenching superheat sensitivity is small, and the heat resistance is higher than alloy steel. And it also has good toughness and machinability at 600℃.
But its carbide is bigger. The strength and toughness will down by the material size increases. Only suited to make normal knife tools. It is not a good material to make large size knife tools and thin blades.
It is widely to make all kinds of cutting tools with medium hardness. Such as turning tools, milling cutters, broaching tools and etc. And also be made cold work mold bases, the fittings that work at high temperatures environment and etc.
It is cobalt high speed steel. It has good hardness in the high temperature. The wear resistance and quenching hardness are high. The hardness of the surface can reach 64-66HRC.
It is great material of all kinds of cutting tools for high-speed cutting with high hardness. Such as hobbing cutter, turning tools, milling cutters and the processing cutting tools for the automatic machine tool.
It also is cobalt high speed steel. Its hot hardness and wear resistance are all better than W18Cr4VCo5. But the toughness is lower. Quenching hardness is reached to 64-66HRC (the hardness of surface).
People always use it to make hobbing cutter, turning tools, milling cutters and etc.
It is cobalt high speed steel with a high content of carbon and vanadium. It has great wear resistance and hardness. And it has good temper resistance and hot hardness. So its service life is longer than other high speed steel.
It is the perfect choice for the material which is difficult to processing. Such as high strength steel, medium strength steel, cold rolled steel, alloy steel and etc. It also is usually used to make cutter gear, threading tool and cold work mold base. But is not able to use to make complex cutting tools which with high degree of accuracy.
It has great hot hardness and toughness. After quenching, the hardness of the surface can up to 64-66HRC. It is molybdenum high speed steel with low tungsten content. The cost is lower than W18Cr4V. And it is one of the most popular of high speed steel.
It is usually used to make drill bit, screw tap, screw die and etc.
After quenching, its hardness of the surface, thermal stability, wear resistance are all better than W6Mo5Cr4-V2. But its strength and impact ductility is lower than W6Mo5Cr4-V2.
People usually use it to make the knife with high machinability. Such as broaching tool, reamer bit and etc.
Its carbide is little and distributes rectangularly. Also has good plasticity and toughness. And the wear resistance is better than W6M05Cr4V2. But the grindability is bad and easy to oxidative decarburization. It is not a good choice for making high-precision complex cutting tools.
It can be used to make all kinds of generic cutting tools. Such as turning tool, milling cutter and etc.
It is Mo-series high speed steel with high carbon and high vanadium. On the base of W6M05Cr4-V3 to improve its average carbon content from 1.05% to 1.20%. And also improve the vanadium content to make its wear resistance get better.