34CrNiMo6 is a low-alloy (chrome-nickel-molybdenum) quenched-and-tempered (QT) steel with medium carbon content. In comparison with QT-steels based on CrMo such as 25CrMo4 and 42CrMo4, the strength level for a given dimension is higher for 34CrNiMo6 at the same time as a good combination of strength and toughness is achievable to larger diameters.
The base steel 34CrNiMo6 is standardised in SS-EN ISO 683-2 but this applies only for hot-rolled bars. Forged, larger-diameter bars are in addition covered by SS-EN 10250-2. The material stocked by Tibnor has better strength and impact toughness than the stipulations of the latter standard. For complete information on the mechanical properties which apply for a given bar dimension, please consult Tibnors Stålvalsguide or the data sheet for 2541M/34CrNiMo6.
Tibnor’s stock standard programme encompasses forged bars of steel 16NiCrS4 in rough-turned execution. The diameter tolerance is then +3/-0 mm.
Welding of 34CrNiMo6 is not to be recommended. The steel is weldable but the procedure is complicated and time consuming. In addition, parts should preferably be quenched-and-tempered again after welding. Machining of QT-steels is generally considered troublesome and calls for high-power machines. Even with such, the cutting speed needs to be limited.
If the application requires a wear-resistant surface, 34CrNiMo6 responds well to surface hardening by both induction hardening and nitriding.