34CrNiMo6M is a low-alloy (chrome-nickel-molybdenum) quenched-and-tempered (QT) steel with medium carbon content. Machinability is for the most part enhanced through M-treatment. In comparison with QT-steels based on CrMo, the strength level for a given dimension is higher for 34CrNiMo6M at the same time as a good combination of strength and toughness is achievable to larger diameters.
Bars available from stock at Tibnor conform completely in regard to chemical analysis and strength to the requirements for steel 34CrNiMo6 in SS-EN ISO 683-2. The guaranteed levels for yield strength, tensile strength and hardness decrease as the dimension increases even if these levels are fixed over stipulated diameter intervals. However, and at variance with 34CrNiMo6 in SS-EN ISO 683-2, the impact strength is guaranteed to 27J better at -20°C. For complete information on the mechanical properties which apply for a given bar dimension, please consult Tibnors Stålvalsguide or the data sheet for 34CrNiMo6M.
The standard execution for the bars stocked in grade 34CrNiMo6M is hot-rolled.
Welding of 34CrNiMo6M 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 but there is a pronounced enhancement of machinability thanks to the M-treatment.
If the application requires a wear-resistant surface, 34CrNiMo6M responds well to surface hardening by both induction hardening and nitriding.