The Reliability of Single-Step and Double-Step Quench and Partitioning Heat Treatments on an AISI 420A Low Carbon Martensitic Stainless Steel

Abstract

The microstructural and mechanical effects of various single-step (SS) and double-step (DS) quench and partition (Q&P) heat treatments applied to an AISI 420A low carbon martensitic stainless steel (MSS) has been studied. The goal with this work is to reach a total elongation (E pct) of 12 pct and an ultimate tensile strength (UTS) above 1200/1300 MPa, but ultimately to achieve a superior strength-ductility balance in comparison to its traditional Quench and Temper (Q&T) counterpart. This is being done by retaining austenite within the steel’s martensitic matrix at room temperature (RT) using novel SS and conventional DS Q&P heat treatments. Considerable work has been done to optimize DS Q&P heat treatments, but little has been done to understand the effects of removing a subsequent heating cycle through SS Q&P heat treatments has on MSSs.