Effect of Heat Treatment Conditions on Retained Austenite and Corrosion Resistance of the X190CrVMo20-4-1 Stainless Steel

• Published in: Metals and materials international Vol. 26; no. 9; pp. 1318 - 1328
• Main Authors: Bignozzi, M. C., Calcinelli, L., Carati, M., Ceschini, L., Chiavari, C., Masi, G., Morri, A.
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.09.2020; Springer Nature B.V; 대한금속·재료학회
• Subjects: Austenite; Austenitic stainless steels; Austenitizing; Carbides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion effects; Corrosion resistance; Corrosion resistant steels; Engineering Thermodynamics; Experimentation; Heat and Mass Transfer; Heat treating; Heat treatment; Image analysis; Machines; Magnetic Materials; Magnetism; Maintenance management; Manufacturing; Martensitic stainless steels; Materials Science; Metallic Materials; Metallurgy; Morphology; Optimization; Processes; Retained austenite; Scanning electron microscopy; Solid Mechanics; Solubilization; Stainless steel; Tempering; Tool steels; 재료공학; Retained austenite; Corrosion; Tool steel; Quenching and tempering; Carbides; Current density-potential curve
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-019-00384-2

In the present work the microstructural characterization of the powder-metallurgy X190CrVMo20-4-1 has been performed and correlated with its corrosion properties. The martensitic stainless steel was hardened at different austenitizing and tempering temperatures. Microstructural analyses were carried out using Scanning Electron Microscopy (SEM–EDS) to define the carbide distribution in the steel matrix. Carbides morphology and retained austenite content were evaluated and correlated to the corrosion behaviour of the different heat-treated steels, investigated by means of electrochemical tests. The results show the presence of M 23 C 6 and M 7 C 3 Cr-V based carbides homogenously dispersed in the matrix in annealed and quenching-and-tempering conditions. The carbides dissolution was evaluated by image analysis in every different heat treatment condition. When low tempering temperature was applied, an increasing in retained austenite content was defined by high austenitizing temperature and elevated carbides solubilization. At high tempering temperature, retained austenite content was not up to 5% nor affected by austenitizing temperature. Contrary to the expectations, HRC hardness was not influenced by the heat treatment conditions and retained austenite content. Corrosion resistance of the different heat-treated samples was found to be mainly influenced by retained austenite volume fraction and the tempering temperature. In particular, high austenitizing temperature and low tempering temperatures allowed the best corrosion resistance among the different heat treatment parameters investigated. The results obtained in the experimentation can provide support to the heat treatment optimization of the steel, widely used in tool and mould applications. Graphical Abstract