Vacuum Quenching Process Curve of High Speed Steel Disc

Material: High Speed Steel

Technical requirements: The hardness of the matrix is 62~64HRC. The deformation is less than o.10mm.

Parts are: φ150mmX30mm disc

The vacuum heat treatment of high-speed steel parts is widely used. The vacuum heat treatment process used by the disc is shown in Figure 1. The vacuum degree of preheating and heat preservation below 1120C is 5~20Pa. When heated to 1120C, the heating chamber is filled with 1X10-Pa. The high-purity ammonia gas (purity of 99.999%) can prevent adhesion between workpieces.

The parts are quenched by vacuum oil cooling. By using appropriate pre-cooling measures before the parts are put into oil, the pre-cooling time is 80~100s. Otherwise, if the parts are directly oil-cooled, the so-called “white bright layer” will be produced on the surface of the parts, which is It is composed of a large number of complex carbides and retained austenite, and there is coarse-grained martensite at the remaining internal junctions, and even melting occurs. After the parts processed by the process of Figure 5-21 are tempered at a high temperature of 540°CX for 3 times, their hardness reaches 62~-64HRC.

Fig 1 Vacuum quenching process curve of W18Cr4V steel parts