Effects of Mn-Depleted Zone Formation on Acicular Ferrite Transformation in Weld Metals under High Heat Input Welding

Fengyu Song; Chaochao Yin; Fusheng Hu; Kaiming Wu

doi:10.3390/ma15238477

Effects of Mn-Depleted Zone Formation on Acicular Ferrite Transformation in Weld Metals under High Heat Input Welding

Materials (Basel). 2022 Nov 28;15(23):8477. doi: 10.3390/ma15238477.

Authors

Fengyu Song¹, Chaochao Yin², Fusheng Hu², Kaiming Wu²

Affiliations

¹ College of Physics, Mechanical and Electrical Engineering, Longyan University, Longyan 364012, China.
² The State Key Laboratory of Refractories and Metallurgy, Hubei Province Key Laboratory of Systems Science on Metallurgical Processing, International Research Institute for Steel Technology, Collaborative Center on Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, China.

Abstract

In this present work, during high heat input welding of the weld metal, different types of Mn-depleted zones were achieved by different cooling rates. The effects of cooling rates on Mn-depleted zone formation and acicular ferrite (AF) transformation were analyzed. The Mn-depleted zone around the inclusions, as well as the interface concentration of Mn atoms, are found to be significantly different with different cooling rates. When the cooling rate is 10 °C/s, the interface concentration of Mn atoms around the inclusions is the lowest, the area of Mn-depleted zone is the smallest, and the proportion of AF in the weld metal is the highest. As the cooling rate decreases further, the interface concentration of Mn begins to rise, the area of the Mn-depleted zone gradually expands, and the proportion of AF decreases. However, when the cooling rate reaches 100 °C/s, only a very small amount of MnS precipitates, no Mn-depleted zone forms around the inclusions, and acicular ferrite cannot be produced effectively in the weld metal.

Keywords: Mn-depleted zone; acicular ferrite; cooling rate; weld metal.

Grants and funding

This research was funded by the support from Fujian Provincial Natural Science Foundation Project (No. 2021J01562), the Young Doctoral Research Initiation Fund of Longyan University (LB201810), Qimai Fund Project in Xinluo District of Longyan City, (No. XLQM007), National Natural Science Foundation of China (No. U20A20279), Taishan Industry Leading Talent Project (No. 2020007) Guangxi Science and Technology Program Project (No. AA22068080), and the 111 Project (No. D18018).