High-speed Steel Vacuum Heat Treatment Process Parameters

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Commonly used high-speed steel vacuum heat treatment process specifications are shown in Table 1

Steel number	Warm up			Quenching heating			Temper			hardness /HRC
	Primary tempera ture/℃	Secondary tempera ture/℃	Vacuum* 133Pa	Tempera ture/℃	Vacuum *133Pa	cool down	Tempera ture/℃	Vacuum *133Pa	cool down
W18Cr4V	600 ~650	850 ~900	10-2~ 10– 3	1260~1280	10-1	N2气 或油	550~580	380 ~500	N2	61~67
95W18Cr4V				1240~1270			550~580			63~68
W6Mo5Cr4V2				1200~1240			540~580			62~67
W6Mo5Cr4V2AI				1200~1230			540~560			64~69
W6Mo5Cr4V3AI				1210~1240			540~560			64~69
W12Cr4V4Mo				1220~1250			550~580			64~68
W18Cr4V3SIAINb				1230~1250			530~560			66~70
W12Mo3Cr4V3Co5Si				1230~1250			540~580			65~70
W7Mo4Cr4 V2Co5				1230~1250			540~590			65~70
W2Mo9Cr4 V2Co8				1190~1200			540~590			65~70
W9Mo4Cr4V3Co10				1220~1240			540~580			65~69
W6Mo5Cr4V5SiNbAl				1220~1240			530~560			64~68

Table 1 Vacuum heat treatment process specification of commonly used high-speed steel

Note:

1. Heating at a vacuum of 10~266Pa to prevent the volatilization of Cr, Mn, AI alloy elements

2. It has poor thermal conductivity and requires multiple preheating.

3. The quenching temperature should be 10-20°C lower than the conventional one.

4. In order to prevent the bright layer of oil quenching surface, use high pressure gas quenching.

5. In order to prevent the workpieces from sticking to each other, the flat surfaces with high smoothness cannot be stacked together.

6. Temper at 530~590°C for 2~3 times to maintain the brightness of 90% N2 + 10% H2.