Guide
Case hardening vs quenching and tempering
Gears and shafts can sit side by side on a parts list and still require two different steels. Case hardening gives a hard case and a tough core. Quenching and tempering gives strength through the cross-section. 16MnCr5 is the first. 42CrMo4 is the second. They do not replace each other.
Two processes
Case hardening (carburising) moves carbon into the case. The core stays tough. Quenching and tempering (Q&T) hardens the carbon that is already in the steel. You cannot “case harden a 42CrMo4” and get the same result as 16MnCr5 – and you cannot Q&T 16MnCr5 into a 42CrMo4 shaft.
- 16MnCr5 / 18CrNiMo7-6 – case hardening, EN 10084
- C45 / 42CrMo4 / 34CrNiMo6 – quenching and tempering, EN 10083
- Nitriding – a third process, its own steel (31CrMoV9)
Which to choose when
Case hardening when the wear is in teeth or a pin, and the core has to withstand impact. Q&T when the whole section has to carry torque. The comparison 16MnCr5 vs 18CrNiMo7-6 is the choice within the case-hardening family. 42CrMo4 vs 34CrNiMo6 is the choice within the Q&T family.
Read more
Send your enquiry
State grade, dimensions and quantity — or attach a drawing. We reply with a quote.