A PROCESS FOR AUSTEMPERING DUCTILE IRON.

摘要

As process for austempering ductile iron includes austenitizing a ductile iron casting of low alloy content followed by quenching the workpiece for a controlled period of time in a quench medium such as water, an aqueous polymer solution or a medium speed quench oil. The workpiece is then austempered in an air tempering furnace, resulting in a ausferrite microstructure essentially free of pearlite and martensite, and with mechanical properties meeting ASTM designation A897-90 "Standard Specification for Austempered Ductile Iron Castings." The process eliminates the need for a molten salt bath for quenching and tempering.