High-speed cobalt-molybdenum steel SK8M, HS2-9-1-8, 1.3247, AISI M42 according to ISO 4957.
| Standard | Steel Grade | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical Composition % | ||||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | Ni: | V: | Co: | W: | Cu: | Nb: | N: | |
| PN | SK8M | |||||||||||||
| 1.05 - 1.20 | <0.4 | <0.5 | <0.03 | <0.03 | 3.5 - 4.5 | 9.0 - 10.0 | <0.4 | 1.0 - 1.4 | 7.5 - 8.5 | 1.3 - 1.9 | - | - | - | |
| ISO | HS2-9-1-8 - 1.3247 | |||||||||||||
| 1.05 - 1.15 | <0.4 | <0.7 | <0.03 | <0.03 | 3.5 - 4.5 | 9.0 - 10.0 | - | 0.9 - 1.3 | 7.5 - 8.5 | 1.2 - 1.9 | - | - | - | |
| DIN | S2-10-1-8 - S 2-10-1-8 | |||||||||||||
| 1.05 - 1.12 | <0.4 | <0.45 | <0.03 | <0.03 | 3.6 - 4.4 | 9.0 - 10.0 | - | 1.0 - 1.3 | 7.5 - 8.5 | 1.2 - 1.8 | - | - | - | |
| GOST | R2AM9K - Р2АМ9К5 | |||||||||||||
| 1.0 - 1.1 | 0.2 - 0.5 | 0.2 - 0.5 | <0.03 | <0.03 | 3.8 - 4.4 | 8.0 - 9.0 | <0.6 | 1.7 - 2.1 | 4.7 - 5.2 | 1.5 - 2.0 | <0.25 | 0.1 - 0.3 | 0.05 - 0.10 | |
1.3247, HS2-9-1-8 steel - specification and application
High-speed cobalt-molybdenum steel with high ductility, abrasion resistance and tempering, which is used for roughing and finishing at high cutting speeds. SK8M materials are used for machining austenitic steels, machine steels, and steels with high hardness (cutters and shaped cutters). Steel is supplied in the form of round, square and flat bars. In the case of forged products, in addition to the above-mentioned cross-sections, discs in a given genre are also provided. SK8M products are delivered in a softened condition.
Mechanical properties of 1.3247, HS2-9-1-8
- Hardness in softened annealed condition: 241 - 302HB
- Hardness after hardening and tempering:
- 300℃ = ~62 HRC
- 350℃ = ~61 HRC
- 400℃ = ~61,5 HRC
- 450℃ = ~63 HRC
- 500℃ = ~66,5 HRC
- 550℃ = ~67,5 HRC
- 600℃ = ~64 HRC
- 650℃ = ~44 HRC
Heat treatment:
- Softeningis carried out at a temperature of 800 - 840 ℃ for a period of about 2-4 hours. Heat the material slowly and evenly. Cool the product together with the furnace, allowing a temperature drop of 10 ℃ every hour to a temperature of 650 ℃. Below the given temperature, allow the temperature to drop in the calm air
- Softening with isothermal transformation(relief annealing) is performed a bit longer and at a higher temperature of 850 - 900 ℃ for a period of 3-5 hours. The cooling process is also carried out slowly with the furnace.
- Hardeningconsists of three heating processes. Firstly, the product is heated to a temperature of approx. 580 ℃, the second heating process is carried out by raising the temperature to 850 - 950 ℃. At the end of the second heating stage, the material is austenitized by heating at 1170 - 1210 ℃. Cooling is carried out in two ways - in oil heated to 60 ℃, or at a temperature of 550 - 570 ℃ in SH430 salt bath.
- Temperingis a two-stage treatment, which is first performed at 560 ℃. The second tempering is carried out at a temperature of 530 ℃. Each of the aforementioned processes should end with slow cooling in the air.
- Nitriding at a temperature 510 - 530℃
The Rolex Metal company in the 1.3247 grade and equivalents provides:
Equivalents and replacements of the grade:
HS2-9-1-8, S2-10-1-8, HS 2-9-1-8, S 2-10-1-8, 1.3247, R11, HS2-10-1-8, W2Mo9Cr4VCo8, 2716, SKH59, SKH 59, M42, 44982, X110MoCo9.8, X110MoCo9-8, R2M8K5F2, Z11ODKCWV09-08-04-02-01, BM42.