PSI - Issue 71

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ScienceDirect

Procedia Structural Integrity 71 (2025) 317–324

Keywords: 17-4 PH stainless steel, martensite, heat treatment, aging, corrosion resistance 1. Introduction The primary identification of precipitation hardening (PH) was noted in Al and Cu alloys. During this process, the mechanical strength and hardness of specific metallic alloys can be enhanced by the dispersion of high-density precipitate particles within the material matrix, which obstructs the movement of dislocations and sliding (Abbaschian and Reed-Hill 2008). This technique generally requires thermal treatment to generate a concentrated solid solution at high temperatures, followed by rapid cooling and aging to promote precipitate formation within the matrix. To improve the outstanding mechanical and corrosion-resistant attributes of steels, this approach was implemented in stainless steels in the 1940s, thereby forming the foundation for the advancement of three unique categories of PH steels: martensitic, austenitic, and semi-austenitic (Hsiao, Chiou et al. 2002). * Corresponding author Tel.: +91-712-2801151 E-mail address: ravikumardumpala@mec.vnit.ac.in Abstract Heat treatment plays a critical role in inducing key microstructural changes necessary to enhance corrosion resistance of 17-4 PH stainless steel (SS). During the process, precipitates form within the metal matrix, contributing to the strength of the martensitic steel. Inconsistencies in the literature concerning the response of 17-4PH SS to heat treatment have been noted. Therefore, this study examines the impact of aging duration on microstructural characteristics, microhardness, and corrosion resistance of material. The solution heat-treatment process consisted of heating the material to 1040 °C for one hour and rapid cooling in water. Subsequently, aging treatment was carried out at 480 °C for varying durations of 1 hour, 4 hours, 8 hours, and 32 hours. Corrosion rates were measured through electrochemical tests using Tafel extrapolation method in a 3.5 wt.% NaCl solution. The findings indicated that aging durations had a significant effect on corrosion resistance, detailed microstructural analysis helped correlate corrosion behaviour with phase changes and precipitation formation. This study offers valuable insights for optimizing heat treatment processes to improve the durability and performance of 17-4PH SS in NaCl corrosion medium. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers 5 th International Structural Integrity Conference & Exhibition (SICE 2024) Effect of Aging Duration on the Microstructure and Corrosion Characteristics of 17-4 PH Stainless Steel G. Narasinga Rao a , Subrat Kumar Baral a , Y. Madhavi b , Sriram Vijayan c , Ravikumar Dumpala a, * a Department of Mechanical Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010, Maharashtra, India. b Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010, Maharashtra, India. c Materials Science and Engineering, Michigan Technological University, Houghton, USA.

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers 10.1016/j.prostr.2025.08.043