The Effect of Drawing Deformation Rate Induced Inhomogeneous Local Distortion on Phase Transformation of 304H Stainless Wire

Qinhua Xu,Chaoqun Li,Jing Liu,Zhixian Peng,Lei Yan,Yong Zong,Zhaoyang Cheng,Jianxin Zhu,Mingyang Li,Ke Peng

doi:10.3390/met10101304

Qinhua Xu, Chaoqun Li + Show 8 more

Open Access

https://doi.org/10.3390/met10101304

Copy DOI

Abstract

The micro/macro magnetic properties, local element distribution, martensite transformation, and mechanical properties of 304H stainless wires are determined for two cold drawing chains. Finite element simulations are used to analyse the local strain and heat generation. The results show that there is obvious inhomogeneity in the magnetic properties, strain/stress relationship, and strain-induced heat within the drawn wires. Comparing wires with the same total strain, a larger area reduction of previous drawing processes contributes to a higher volume of the martensite phase, while a smaller area reduction of the first process results in an inhibited phase transformation. A higher single strain in the first drawing process leads to additional heat generation at the subsurface of the wire, which would eventually retard the martensite transformation. The inhomogeneous deformation-induced differences in the grain size affect the stability of austenite and transform the final martensite.

Highlights

Austenite series stainless steel wires have earned a reputation for their outstanding corrosion resistance, weldability, and good mechanical properties and surface finish that have made them widely applicable in the petroleum industry, chemical instrumentation, and nuclear engineering [1].Cold drawing is the most common wire processing technology and results in refined and fiberized austenite phases due to dramatic deformations
The increased area reduction caused the deformation to become more apparent and the number of deform-induced twin crystals increased in both drawing chains
For the drawing chain B, the lower area reduction of the first drawing pass caused undeformed austenite to remain after a certain number of deformation twins, as seen in wire B-1

Summary

Introduction

Cold drawing is the most common wire processing technology and results in refined and fiberized austenite phases due to dramatic deformations. The relatively low stacking fault energy of austenite allows martensite transformations due to cold drawing [2,3]. It is important to perform both theoretical and production research on the regular deformation-induced martensite (DIM) transformation. The factors that affect the metastable austenite phase transformation are the chemical composition, microstructure, temperature, stress/strain characteristics, and their combination [4]. The martensite transformation criteria rely on the stacking fault energy (SFE) of austenite and the phase transformation temperature of martensite Ms [5]. Several works have reported that the low SFE (

Methods

Results

Discussion

Conclusion