New aero-engine bearing steel M50NiL nitrogen carburizing hardened layer of micro-fracture toughness

M50NiL steel for aerospace turbine engines developed a new type high-temperature carburizing bearing steel to replace the existing M50 steel [1]. The steel in the non-carburized state fracture toughness of steel is about 2 times higher than the M50, but the steel after carburizing heat treatment on the fracture toughness after the study has so far rarely reported.

Three-point bending, unilateral V-notched specimen, along the gap carburizing, carburizing hardened layer test fracture toughness test methods to study carbon, nitrogen and cold treatment and tempering temperature on M50NiL fracture toughness of the nitrided layer of steel impact. The results show that the carburized layer in additional trace of nitrogen into the secondary hardening and fracture toughness of the increase will benefit, it makes the fracture toughness of hardened layer was significantly higher than conventional steel case-hardened steel and M50 steel