Standard carburizing steel 18CrNiMo7-6 is often used when high hardenability is required, but due to its highly fluctuating price, there has always been an incentive to develop Ni-free steel grades. The 23MnCrMo5-5-2 — or Jomasco 23mod — has been developed for this purpose. But to ensure smooth substitution within existing production lines, a number of points must be addressed: first, checking the response to carburizing treatments; and second, having similar mechanical properties with identical tooth root bending performance on gears. The latter is the purpose of this paper.

The development of a new, gas-carburized gear steel, necessitated by a customer-driven specification, has not only increased the power density in an existing gearbox design, but has done so without requiring any significant change to production processes or heat treatment equipment.

This paper summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.

Much has been argued about the “buy American” clause included in the American Recovery and Reinvestment Act of 2009.