Comparison
16MnCr5 vs 18CrNiMo7-6
Both are case-hardening steels. After carburising and hardening you get a wear-resistant case and a tough core. The difference is alloying and thus how large a gear the core can still carry. 16MnCr5 is the workhorse. 18CrNiMo7-6 is the heavy choice when nickel and molybdenum are required.
Same process, different material
Case hardening is not quenching and tempering. 42CrMo4 is through-hardened. 16MnCr5 and 18CrNiMo7-6 are carburised. You choose between the two on cross-section and core toughness – not because one is a “better steel”.
- 16MnCr5 · 1.7131 – Mn-Cr, standard for gears and bolts
- 20MnCr5 · 1.7147 – slightly more carbon, deeper case or larger part
- 18CrNiMo7-6 · 1.6587 – Ni-Cr-Mo, large wheels and planetary stages
When to step up
Stay with 16MnCr5 as long as the part and the case depth fit EN 10084 for 1.7131. 20MnCr5 when the case has to go deeper without going to nickel. 18CrNiMo7-6 when the core of a large wheel still has to be tough after case hardening. It is not a switch to 34CrNiMo6 – that is a different Q&T steel.
Delivery
Bar, typically soft annealed or +FP, ready for machining before carburising. We saw to size. The case hardening itself is done by the heat treater you or we point to. 3.1 on the material you received – not on a hardness that only comes after carburising.
Frequently asked questions
- Is 18CrNiMo7-6 a better 16MnCr5?
- It is a heavier case-hardening steel for large cross-sections. In a Ø40 gear, 16MnCr5 is most often the right – and cheaper – choice.
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State grade, dimensions and quantity — or attach a drawing. We reply with a quote.