Steel R9M4K8
R9M4K8 steel
Steel R9M4K8: a classifier of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperature, physical, mechanical, technological and foundry properties for the grade — Steel R9M4K8.
General information on steel R9M4K8
| Delivery type |
| Bar stock, including shaped: GOST 19265−73, GOST 2590−71, GOST 2591−71. Calibrated bar GOST 19265−73, GOST 7417−75. Grinded rod and silversilver GOST 19265−73, GOST 14955−77. Strip GOST 19265−73, GOST 4405−75. Forged and forged blanks GOST 19265−73, GOST 1133−71. |
| Application |
| For machining of high-strength stainless steels and heat-resistant alloys under conditions of increased heat cutting edge: gear cutting tools, cutters, shaped cutters, countersinks, taps. |
Chemical composition of R9M4K8 steel
| Chemical element |
% |
| Vanadium (V) |
2.3−2.7 |
| Tungsten (W) |
8.5−9.5 |
| Cobalt (Co) |
7.5−8.5 |
| Silicon (Si), not more than |
0.50 |
| Manganese (Mn), not more than |
0.50 |
| Molybdenum (Mo) |
3.8−4.3 |
| Nickel (Ni), not more than |
0.40 |
| Sulfur (S), not more than |
0.030 |
| Carbon (C) |
1.0−1.1 |
| Phosphorus (P), not more than |
0.030 |
| Chromium (Cr) |
3.0−3.6 |
Process properties of steel R9M4K8
| Forging temperature |
| The beginning 1180, the end 880. Cooling in the wells at 750−800 C. |
| Grindability |
| reduced (GOST 19265−73). |
Steel R9M4K8 critical point temperature
| Critical point |
°С |
| Ac1 |
800 |
| Ac3 |
840 |
| Ar3 |
790 |
| Ar1 |
750 |
Impact toughness of steel R9M4K8
Impact toughness, KCU, J/cm2
| Delivery condition, heat treatment |
KCU |
HRCe |
| Hardening 1220 С, oil. Tempering 500 C three times for 1 h. |
|
68 |
| Tempering at 1220 °C in oil. Tempering 540 C three times for 1 hour. |
|
69 |
| Tempering at 1220 C in oil. Tempering at 580 C three times for 1 hour. |
|
67 |
| 67 Quenching at 1220 °C in oil. Tempering 620 C three times for 1 hour. |
|
63 |
| Tempering at 1220 C in oil. Tempering 660 C three times for 1 hour. |
|
56 |
| Tempering at 1220 °C in oil. Tempering at 520 C |
18 |
|
| Tempering at 1220 °C, oil. Tempering 540 C |
19 |
|
| Tempering at 1220 °C, oil. Tempering 560 C |
21 |
|
| Tempering at 1220 °C, oil. Tempering 580 C |
20 |
|
Physical properties of steel R9M4K8
| Test temperature, °C |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Modulus of normal elasticity, E, GPa |
229 |
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| Torsional shear modulus of elasticity G, GPa |
87 |
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| Steel density, pn, kg/m3 |
8300 |
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| Thermal conductivity coefficient W/(m — °C) |
|
25 |
27 |
28 |
29 |
30 |
31 |
32 |
|
32 |
Heat resistance, red resistance of steel R9M4K8
Heat resistance
| Temperature, °С |
Time, h |
Hardness, HRCe |
| 630 |
4 |
59 |
