Optimization of steel metallurgy to improve broach tool life

摘要

A steel for use as a broachable workpiece having a substantially pearlite-free microstructure whereby the service life of the broach tool is maximized. Formation of pearlite is suppressed by alloy modification; on-line processing; off-line processing; or combinations of these techniques which control the microstructure and hardness levels. The workpiece is broached into the form of a powertrain component such as, for example, a gear or race which can be surface hardened after broaching by one of carburizing, nitriding, or induction hardening depending upon the carbon content of the steel. Disclosed are steel compositions and processing methods for making the steel, the broachable workpiece and the broached and surface hardened powertrain article.