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Ni-Cr-Mo Steel Equivalent Chart
Ni-Cr-Mo Steel KS Specifications — 3 sizes
KS D 3867
SNCM439 (KS/JIS) = 40NiCrMo7 (DIN) = 4340 (ANSI): equivalent Ni-Cr-Mo ternary alloy steels with the best combination of toughness and strength.
Practical Notes
- SNCM439 Ni-Cr-Mo triple alloy achieves uniform heat treatment even in large cross-sections. Optimal for large shafts and crankshafts.
- Expensive due to alloying elements. Use SCM440 first where its strength suffices to save cost.
KSNi-Cr-Mo Steel
3 sizes| KS | JIS | DIN | ANSI/ASTM | Category | Note |
|---|---|---|---|---|---|
| SNCM220 | SNCM220 | 20NiCrMo2 | 8620 | Ni-Cr-Mo Steel | Carburizing Gear·Pin |
| SNCM439 | SNCM439 | 40NiCrMo7 | 4340 | Ni-Cr-Mo Steel | Aerospace·High Strength Shaft |
| SNCM815 | SNCM815 | 15NiCr13 | 3315 | Ni-Cr-Mo Steel | Large Carburizing Parts |
Key Features
- SNCM439/SNCM630 grades; Ni addition ensures cryogenic toughness and large-section hardenability
- Yield strength 900–1200 MPa class; structural material for extreme environments like aerospace/nuclear
- Uniform hardening possible to core of large forgings; segregation control essential
Key Applications
Aircraft landing gear, large crankshafts, nuclear pressure vessel bolts, turbine rotors, marine propeller shafts
FAQ
Why is SNCM more expensive than SCM?
Due to nickel addition, which greatly improves toughness for uniform heat treatment even in large sections. Use SCM where sufficient to save cost.