Journal Published Online: 14 June 2018
Volume 7, Issue 4

An Investigation into the Reverse Transformation Mechanisms in the Heat Treatment of Austenitic Stainless Steel



Cold working of austenitic stainless steel results in the formation of α′-martensite (ferromagnetic) within the host material (paramagnetic). The role of α′-martensite and carbide precipitation in the reverse transformation mechanism during the heat treatment of AISI 304 is presented. A magnetic Barkhausen noise (MBN) measurement technique was employed to characterize the transformation mechanisms. MBN was found to be an effective tool for studying the transformation mechanisms of austenite to α′-martensite during material deformation as MBN and the ferromagnetic phase showed a good correlation. AISI 304 specimens plastically strained to 51 % were subjected to annealing heat treatment (from 100°C to 1,100°C) for 30 minutes. The α′-martensite to austenite reversion mechanisms were found to have a significant effect on residual stress and materials magnetic properties, thus limiting MBN effectiveness in studying the reverse transformation process. Residual stresses go from tensile to compressive between 500°C and 600°C as a result of the transformation mechanisms, as the austenitic phase is larger than α′-martensite and therefore compresses the remaining α′-martensite. It is suggested that ϵ-martensite has a significant role in the dislocation structural mechanisms in the heat treatment of AISI 304.

Author Information

O’Sullivan, D.
South Eastern Applied Materials (SEAM) Research Centre, Waterford Institute of Technology, Waterford, Ireland
Raghavendra, R.
South Eastern Applied Materials (SEAM) Research Centre, Waterford Institute of Technology, Waterford, Ireland
Cotterell, M.
Department of Mechanical and Process Engineering, Cork Institute of Technology, Cork, Ireland
Mészáros, I.
Department of Materials Science and Engineering, Budapest University of Technology and Economics, Budapest, Hungary
Tanner, D. A.
Bernal Institute & School of Engineering, University of Limerick, Castletroy, Limerick, Ireland
Pages: 12
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Stock #: MPC20170093
ISSN: 2379-1365
DOI: 10.1520/MPC20170093