Effect of Nickel Content and Cooling Rate on the Microstructure of as Cast 316 Stainless Steels

作者：Lei Chen, Yang Wang, Yafeng Li, Zhengrui Zhang, Zhixuan Xue, Xinyu Ban, Chaohui Hu, Haixiao Li, Jun Tian, Wangzhong Mu, Kun Yang, Chao Chen · 发表于：Crystals · 年份：2025 · DOI：10.3390/cryst15020168 · 被引用次数：19 · 研究领域：Microstructure and Mechanical Properties of Steels、High Temperature Alloys and Creep、Hydrogen embrittlement and corrosion behaviors in metals

To meet the requirement of low magnetic permeability, which, in turn, lowers the ferrite content of castings, of special interest is 316 stainless steel, whose low ferrite content renders it suitable also for nuclear power applications. Therefore, the effects of the composition and cooling rate of 316 stainless steel castings on the ferrite content are investigated. Three 316 stainless steel continuous casting samples with different compositions (primarily differing in the Ni content) are studied, i.e., low-alloy type (L-316), medium-alloy type (M-316), and high-alloy type (H-316). The austenite-forming element nickel of three different industrial samples is 10%, 12%, and 14%, respectively. The effect of the cooling rate on the ferrite content and precipitation phases of the high Ni content of the 316 stainless steel casting (H-316) is studied by remelting experiments and different methods of quenching of liquid steel. In both cases, the ferrite content and the precipitate phases in the microstructure are analyzed using SEM and EBSD. The results indicate that compositional changes within the 316 stainless steel range lead to changes in the solidification mode. In the L-316 casting, solidified by the FA mode (ferrite–austenite mode), ferrite precipitates first from the liquid phase, followed by the formation of austenite, and the ferrite content is 11.2%. In contrast, the ferrite content in the M-316 and H-316 castings, solidified by the AF mode (austenite–ferrite mode), is 2....