Comparative study on the effect of Y content on grain refinement in the simulated coarse-grained heat-affected zone of X70 pipeline steels

Y X Cao; X L Wan; Y H Hou; Y Liu; M M Song; G Q Li

doi:10.1016/j.micron.2019.102758

Comparative study on the effect of Y content on grain refinement in the simulated coarse-grained heat-affected zone of X70 pipeline steels

Micron. 2019 Dec:127:102758. doi: 10.1016/j.micron.2019.102758. Epub 2019 Oct 3.

Authors

Y X Cao¹, X L Wan², Y H Hou¹, Y Liu¹, M M Song¹, G Q Li³

Affiliations

¹ The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China.
² The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China; Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China. Electronic address: wanxiangliang@wust.edu.cn.
³ The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China; Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China. Electronic address: liguangqiang@wust.edu.cn.

PMID: 31634690
DOI: 10.1016/j.micron.2019.102758

Abstract

This study aims to investigate the influence of Y content on grain refinement in the simulated coarse-grained heat-affected zone (CGHAZ) of X70 pipeline steels. The results explored that two different grain refinement mechanisms were presented in 0.034 wt.%-Y and 0.075 wt.%-Y steels, respectively. The Y₂O₂S inclusions and YP precipitates are formed in 0.034 wt.%-Y steel instead of the YP inclusions and more YP precipitates in 0.075 wt.%-Y steel. The grain refinement mechanism in the simulated CGHAZ of 0.034 wt.%-Y steel mainly depends on the formation of acicular ferrite induced by Y₂O₂S inclusion. Whereas, the grain refinement mechanism in the simulated CGHAZ of 0.075 wt.%-Y steel primarily relies on the austenite boundary pinning effect by higher density of YP precipitates.

Keywords: Grain refinement; High strength low alloy steel; In-situ observation; Microstructure; Yttrium treatment.

Publication types

Research Support, Non-U.S. Gov't