Microstructural Changes During Short-Term Heat Treatment of Martensitic Stainless Steel\u2014Simulation and Experimental Verification

N Schmidtseifer,S Weber

doi:10.1007/s11661-021-06280-y

N Schmidtseifer, S Weber

Open Access

https://doi.org/10.1007/s11661-021-06280-y

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Abstract

Short-term heat treatments of steels are used for tools and cutlery but also for the surface treatment of a variety of other workpieces. If corrosion resistance is required, martensitic stainless steels like AISI 420L or AISI 420MoV are typically used. The influence of short-term heat treatment on the different metastable states of the AISI 420L steel was examined and reported in this article. Starting from a defined microstructural state, the influence of a short-term heat treatment is investigated experimentally with the help of a quenching dilatometer and computer assisted simulations are carried out. With the results obtained, a simulation model is built up which allows to compute the microstructural changes during a short-term heat treatment to be evaluated without the need for an experiment. As an indicator, the value of the martensite start temperature is calculated as a function of different holding times at austenitizing temperature. The martensite start temperature is measured by dilatometry and compared to calculated values. Validation of simulated results reveals the potential of optimizing steel heat treatment processes and provides a reliable approach to save time, resources and energy.

Highlights

TOOL steels are used when special challenges are posed to the properties of the material
Chromium must be dissolved in the matrix and should not be bound in carbides to provide matrix corrosion resistance
Chromium can be dissolved in the matrix and provide corrosion resistance.[2]

Summary

Introduction

TOOL steels are used when special challenges are posed to the properties of the material. The most important alloying element, besides carbon, is chromium. Chromium must be dissolved in the matrix and should not be bound in carbides to provide matrix corrosion resistance. The lower limit value is a content of 12 wt pct chromium.[1] By heat treatment, chromium can be dissolved in the matrix and provide corrosion resistance.[2] For this purpose existing carbides must be dissolved. In this way, carbon is released to the fcc matrix, providing hardenability.

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