Aubert & Duval presents at 10th International Symposium on Bearing Steel Technologies

The traditional corrosion resistant bearing steel family is largely represented by 440C, X65Cr14, and several specialized case hardening (nitrided or carburized) grades. For through hardening processes, a major innovation was made when nitrogen alloying was applied to enhance the corrosion resistance, particularly for secondary hardened high temperature corrosion resistant rolling bearing steel grades. Nitrogen may be added by pressurized electro-slag remelting (PESR) or in the ladle, the later process being a cost-effective method. The ladle treated nitrogen alloy variant achieving similar properties to PESR steel is designated X40CrMoVN16-2 (XD15NW). For the carburizing process, some advanced but complex solutions have been designed, many of them with high co-content enhancing temperature and corrosion resistance. We will see how some existing and simple steel solutions, when adequately fine-tuned for carburizing, can bring benefits with relevant functional properties and stable processing of the steel designated X12CrNiMoV12-3 (CX13VDW). This paper will focus on the through hardening and carburizing steel technologies for the martensitic corrosion resistant bearing grades. The technologies resulting in improved performance relative to the traditional bearing material family are presented with respect to alloy development, microstructure control, and property enhancement, leading to the development of these steels.