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.