文献类型：期刊文献

英文题名：Crucial Microstructural Features to Determine the Mechanical Properties of Welded Joints in a Cu-Containing Low-Carbon Low-Alloy Steel After Postweld Heat Treatment

作者：Wang, Jinliang[1];Dong, Guangqi[2];Li, Youchi[1];Xi, Xiaohui[1];Chen, Liqing[2]

机构：[1]Guangdong Ocean Univ, Sch Mech & Power Engn, Zhanjiang 524088, Peoples R China;[2]Northeastern Univ, State Key Lab Rolling & Automat, 3-11 Wenhua Rd, Shenyang 110819, Peoples R China

年份：2022

卷号：53

期号：9

起止页码：3493

外文期刊名：METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

收录：SCI-EXPANDED(收录号：WOS:000833435300001)、、EI(收录号：20223112527439)、Scopus(收录号：2-s2.0-85135216025)、WOS

基金：This work is supported by the National Natural Science Foundation of China (Grant No. 52101133) and the Science and Technology Projects of Zhanjiang with the Contract Nos. 2021E05003 and 2021B01039.

语种：英文

外文关键词：Alloy steel - Austenite - Bainite - Grain boundaries - Low carbon steel - Martensitic transformations - Steel metallurgy - Strengthening (metal) - Tempering - Tensile strength - Welded steel structures - Welding - Welds

外文摘要：The effect of welding and postweld heat treatment on the microstructural characteristics and mechanical properties of a Cu-containing low-carbon low-alloy steel was studied. The obtained results indicated that ferrite, bainite, and coarse Cu-rich precipitates formed in the weld metal (WM) were responsible for its low impact energy of 57 J at - 40 degrees C. To obtain a good balance between strength and toughness in the WM, different heat treatments were employed. The obtained results demonstrated that direct tempering had a negligible effect on strength and toughness, but the addition of intercritical annealing to the conventional quenching and tempering process resulted in a significant increase in toughness and a slight decrease in tensile strength. The impact energy was increased to beyond 144 J, and the tensile strength was maintained at a high level of 958 MPa. The optimal microstructure benefiting both toughness and strength was found to primarily comprise intercritical ferrite, tempered martensite/bainite, reversed austenite, and fine Cu-rich precipitates. The toughening mechanism can be explained by the strain-induced martensitic transformation of reversed austenite and the retarding crack propagation effect of high-angle grain boundaries with a misorientation of more than 45 deg. The strengthening mechanism can be rationalized in terms of precipitation-strengthening and the strain-induced martensitic transformation of reversed austenite.