Effects of Microalloying and Heat-Treatment Temperature on the Toughness of 26Cr-3.5Mo Super Ferritic Stainless Steels

• Published in: Acta metallurgica sinica : English letters 2014-06, Vol.27 (3), p.407-415
• Main Authors: Ma, Li, Han, Jian, Shen, Junqi, Hu, Shengsun
• Format: Article
• Language: English
• Subjects: Atmospheric corrosion; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium; Cleavage; Corrosion and Coatings; Corrosion resistance; Crack initiation; Crack propagation; Crystal structure; Deformation; Ductile fracture; Ductile-brittle transition; Equilibrium; Ferritic stainless steels; Fracture toughness; Heat treatment; Hot rolling; Impact strength; Materials Science; Mechanical properties; Metallic Materials; Microalloying; Molybdenum; Nanotechnology; Nickel; Ni含量; Optimization; Organometallic Chemistry; Phase composition; Precipitation; Scanning electron microscopy; Spectroscopy/Spectrometry; Stainless steel; Stress corrosion cracking; Temperature; Tensile strength; Tribology; Yield stress; 冲击韧性; 延性断裂; 微合金化; 热处理工艺; 热处理温度; 热处理过程; 超级铁素体不锈钢
• ISSN: 1006-7191; 2194-1289
• DOI: 10.1007/s40195-014-0070-2

The effects of Ni content and heat-treatment process on the toughness of a super ferritic stainless steel with 26 wt% Cr and 3.5 wt% Mo were investigated. It was found that with the increase of Ni content, the Charpy impact toughness improved remarkably, and transformed from cleavage brittle fracture to the most ductile fracture. There were no obvious differences between the high- and low-Ni contents on the microstructure and mechanical properties since the addition of Ni did not influence crystal structure, phase composition, and precipitation of ultra pure ferritic stainless steels. Meanwhile, the heat-treatment process was a key point to maintain a high level of toughness by optimizing structure and removing detrimental precipitation, i.e., chi phase.