Tools Steel Oil Quenching

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Adding a certain type and quantity of alloying elements on the basis of carbon tool steel is called alloy tool steel. Compared with carbon tool steel, alloy tool steel has higher hardness and wear resistance, and also has better hardenability, red hardness and tempering stability.

1. Low Alloy Cutting Tool Steel Oil Quenching

Low-alloy cutting tool steel is a steel with a small amount of alloying elements added to the carbon tool steel. Its W.=0.75%~1.5% range to ensure the hardenability of steel and the need to form alloy carbides. The added alloying elements mainly include silicon, manganese, chromium, tungsten, vanadium and so on. Among them, the main function of silicon, manganese and chromium is to improve the hardenability of steel.

Increase the strength of steel; tungsten and vanadium form carbides, refine grains and improve the hardness, wear resistance and thermal hardness of steel. Therefore, the hardenability of low-alloy tool steel is better than that of carbon tool steel.

The shape and cracking tendency are reduced. However, due to the small amount of alloying elements added, the thermal hardness of steel is still not too high, and the general working temperature should not be higher than 300°C.

2. High-speed Steel Oil Quenching

The cutting tool made of high-speed steel can be cut at a higher cutting speed than the low-alloy cutting tool steel when in use, so it is called high-speed steel. It is characterized by its thermal hardness of up to 600°C, and it can keep the cutting edge sharp for a long time during cutting, so it is also called “front steel” and also has high strength, hardness and hardenability. The martensite structure can be obtained by cooling in the air during quenching.

High-speed steel can only obtain excellent properties after correct quenching and tempering. The quenching heating temperature of high-speed steel is very high (1200~1300°C), the purpose is to make carbide as much as possible to dissolve into austenite, thereby improving hardenability, tempering stability and hot hardness. Due to the poor thermal conductivity of high-speed steel, one or two preheating must be carried out during quenching and heating. As shown in Figure 1.

Figure 6-5 Quenching and tempering process curve of W18Cr4V steel

The structure of high-speed steel after quenching is cryptocrystalline martensite, granular carbides and about 25% retained austenite, as shown in Figure 2.

Figure 6-6 The structure of W1 8Cr4V steel after quenching (400X)

Shanghai Geheng Vacuum Technology Co., Ltd. is a vacuum heat treatment furnace manufacturer with many years of experience in design, manufacturing and production. Mainly produce vacuum heat treatment furnace, vacuum sintering furnace, vacuum brazing furnace, New Energy And Environmental Protection Equipment and other vacuum equipments.Provide customized services, equipment work area can be based on customer output.