Treatment of High-strength CFB-QP Forged Parts by Stepwise Water Quenching

The forging industry, and the production of high-strength forged parts in particular, saw no substantial progress in recent decades. High-strength parts continued to be made of well-tried steel grades which meet the economic and environmental production requirements, using mainly the conventional quenching and tempering. However, the latest findings in physical metallurgy of higher-silicon steels suggest that high-strength forgings can also be obtained by producing bainitic and martensitic microstructures. The first are of the CFB (carbide-free bainite) type and the latter comprise the QP (quenching-partitioning) microstructure. At greatly reduced processing costs, properties comparable to tempered martensite can thus be attained.