PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Vacuum sintered powder alloy high speed steel

Powder high speed steel:

The alloy powder manufacturing technology has been constantly improved and broken through to develop high-quality powder alloy high-speed steel, referred to as powder high-speed steel.

The difference between powdered high-speed steel and traditional high-speed steel

Traditional high-speed steel is mostly made by using larger arc-melted steel and adding required or insufficient alloy raw materials. After degassing and slag removal processes (commonly known as secondary refining), it is poured into a crucible and then cast into steel ingots. Alloy steel ingots are hot forged and then formed into steel bars of the required size.

The production of powdered high-speed steel: usually a smaller furnace is used, and after fine secondary refining, the required molten steel with stable composition is smelted. The molten steel flows out through the fine pouring hole, and is blown into atomization by high-pressure gas. , an extremely fine, nearly round steel grain powder is formed in an instant. After strict screening, the inner steel ingot is inverted into a tank, evacuated to form a complete airtight, and then subjected to vacuum sintering and pressure equalization treatment. The inside of the powdered steel ingot forming tank reaches 100% Strong (without any pores). After completion, the powder steel ingot is completely annealed and then hot forged into a black steel bar of the desired size. Since there is a decarburization layer on the surface, it must be completely removed. In particular, the powder high-speed decarburization layer is thicker than traditional steel materials and must be completely removed. Removal, the following table shows the minimum thickness value of the black skin decarburization layer that must be removed.

Advantages of vacuum sintered powder high speed steel compared with traditional high speed steel:

1.Non-directional: Powder high-speed steel is made by pressing and sintering extremely fine steel grains, so the compressive strength, impact resistance, flexural strength, and toughness of each point are the same. There is no difference between what is commonly known as “straight wire” and “horizontal wire” in the same piece of material, as well as the production of mesh structures and water textures, as shown in the diagram above.

2.The crystal particles are fine and uniform: Powder high-speed steel is composed of extremely fine steel grain powder, and then sintered by HIP, the internal structure is fine and uniform. In traditional high-speed steel, carbides precipitate too early when making alloy steel ingots, resulting in enlarged crystalline particle groups and uneven sizes.

3.Vacuum heat treatment can improve hardness: Take high-speed steel of the same series as an example: traditional high-speed steel (JIS SKH-51: AISI M2) generally has a hardness of HRC 62-64 after heat treatment, while the same type of Mo (鈤) powder high-speed steel The hardness after heat treatment is HRC63~66, taking 25t x 100 x 100 as an example. During heat treatment, the quenching temperature (Worthfield ironization temperature) of powder high-speed steel is 30℃~80℃ lower than traditional high-speed steel, and the quenching allowable cooling time is longer than traditional high-speed steel. High-speed steel is long, nearly air-cooled and has excellent high hardness values.

4.Heat treatment deformation reduction: Powder high-speed steel is combined with extremely fine steel grain powder. After heat treatment, the size of the material will be larger than the original size, and will increase in all directions at the same time. However, traditional high-speed steel will increase in size after heat treatment due to its directional nature. There are large inconsistencies, and the size may even be reduced in some places, deforming the original body.

5.No segregation: In traditional high-speed steel, the distribution of each element during the smelting process is not very uniform. Therefore, when each metal element combines with carbon to form carbide during heat treatment, the distribution position is unbalanced and segregation occurs. The lifespan varies in processing or use, and quality and lifespan are difficult to control. This is not the case with powdered high-speed steel. Therefore, when the hardness of powdered high-speed steel is the same as that of traditional high-speed steel, powdered high-speed steel has better processability and is not easily deformed.

6.No non-metallic intervening matter: Because every fine steel grain (powder) of powdered high-speed steel has been strictly screened, the contained impurities and non-metallic matter are close to zero, and the composition is very stable after molding. Especially with the widespread use of wire cutting nowadays, the presence of non-metallic intervening objects in each piece of material should not affect the working hours and quality.

7.Wear resistance: When the heat treatment and quenching temperature are the same, the hardness of powder high-speed steel is higher than that of traditional high-speed steel, so its wear resistance is also better than traditional high-speed steel, and the particles are small and uniform, without segregation. The wear resistance depends on the use situation. It can be increased by 50%~200% depending on the difference.

8.Toughness: When traditional high-speed steel wants to reach the same hardness as powdered high-speed steel, its quenching temperature will inevitably increase, causing the internal carbide particles to crystallize and grow coarser, thereby reducing the toughness. The crystallized particles of powdered high-speed steel are fine and uniform, and have no directionality, so the toughness is reduced. Better.

Classification of powder high speed steel

The difference between powdered high-speed steel and traditional high-speed steel lies in the differences in manufacturing procedures and the addition of some insufficient metal elements. Steel materials with various composition elements can also be smelted according to needs. Generally speaking, like traditional high-speed steel, it is divided into two large series: Mo (molybdenum) series and W (tungsten) series. Mo-based materials have better toughness, W-based materials have better wear resistance, higher high-temperature hardness, and stronger impact resistance.

Vacuum heat treatment of powder high speed steel

The use of any kind of steel depends largely on the choice and conditions of heat treatment. Generally speaking, the vacuum quenching temperature of Mo-based powder high-speed steel should not be higher than 1200°C (each manufacturer has different compositions). The quenching temperature of W series powder high speed steel cannot be higher than 1240℃. The success or failure of vacuum heat treatment of powdered high-speed steel pays special attention to the vacuum tempering procedure. Mo element “leakage” should be prevented during vacuum heat treatment of Mo-based powder high-speed steel.

Applications of powdered high speed steel:

Powder high-speed steel has high wear resistance, good toughness and excellent workpieces, and can be ground to a very smooth surface.

1.Replace traditional high-speed steel for various forming tools.

2.It is widely used in precision continuous punching dies, deep drawing dies and analysis bending dies.

3.Used for parts that require wear resistance (easier to process than tungsten carbide alloy).

4.It is used for materials with surface requirements such as mirror surfaces that are easy to remove and can withstand high temperatures.

5.It is used for semiconductor molds and diodes that need to be stable in size and cannot change in size during long-term use.

Powder metallurgy high-speed steel has good mechanical properties and is suitable for manufacturing: tools that are prone to chipping under intermittent cutting conditions, tools with high strength and must have sharp cutting edges, such as gear shapers, hobs, milling cutters, and use under high-pressure dynamic loads. of knives. It has small carbide segregation, fine grains, and good grindability. It is suitable for manufacturing: large-size tools, precision tools, and complex tools. This type of material has high thermal hardness at high temperatures and is suitable for making tools for difficult-to-machine materials. It is indeed comprehensive. The production process of powder metallurgy high-speed steel is complex and the cost is high.