Effects of Welding Wire Composition on the Microstructures and Mechanical Properties of Ultra-high Strength Armored Steel Welded Joints
ZHENG Daoyou1, XU Yuxin2, WANG Suyu2, WANG Wenquan2,*
1 College of Optoelectronic Manufacturing, Zhejiang Industry & Trade Vocational College, Wenzhou 325002, Zhejiang, China 2 School of Materials Science and Engineering, Jilin University, Changchun 130022, China
Abstract: 4.5 mm and 9.0 mm thick ultra-high strength armored steels were welded successfully by robotic gas-shielded arc welding technique, and the effects of welding wire (MG70S-6, ER307Si) composition on the microstructures and mechanical properties of welded joints were investigated. The microstructures and phase structures of welded joints were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive analysis (EDS) and X-ray diffraction (XRD), and the hardness, tensile properties and impact toughness of welded joints were also examined. The results showed that the welded joints were well formed without visible defects such as lack of fusion, pores or cracks. The microstructures of weld metals were composed of flaky martensite, acicular ferrite and a small amount of granular bainite, and the microstructures of the fully quenched zone were martensite and bainite. The incomplete quenched zone was composed of mixed microstructure of martensite and ferrite, and reticular cementite was precipitated in the tempering zone. The softening phenomenon of the heat-affected zone of the welded joint was relatively obvious, and the joint strengths were all lower than those of base metals, and the fracture mainly occurred in the weld zone, reflecting the characteristics of brittle fracture. The room temperature impact energy of the 9.0 mm armored steel joint welded with ER307Si reached 94 J, which could meet the application requirements.
1 Cao H Q, Zhao B R, Xu L T. Armor protection technology, Ordnance Industry Press, China, 2012 (in Chinese) 曹贺全, 赵宝荣, 徐龙堂. 装甲防护技术, 兵器工业出版社, 2012. 2 Zhang H J, Li T, Wang J Q, et al. Journal of Iron and Steel Research, 2017, 29(4), 323 (in Chinese). 张海军, 李潭, 王晶琦, 等. 钢铁研究学报, 2017, 29(4), 323. 3 Chen J S, Gao Y L, Sun B S, et al. Journal of Ordnance Equipment Engineering, 2020, 41(10), 1 (in Chinese). 陈京生, 高永亮, 孙葆森, 等. 兵器装备工程学报, 2020, 41(10), 1. 4 Tan J, Zhang Y. Acta Armamentarii, 2013, 34(1), 115 (in Chinese). 谭俊, 张勇. 兵工学报, 2013, 34(1), 115. 5 Chen G, Dai L W, Sun Z F, et al. Journal of Ordnance Equipment Engineering, 2017, 38(9), 58 (in Chinese). 陈功, 代璐蔚, 孙智富, 等. 兵器装备工程学报, 2017, 38(9), 58. 6 Maweja K, Stumpf W. Materials Science & Engineering A, 2006, 432(1-2), 158. 7 Jena P K, Kumar K S, Krishna V R, et al. Engineering Failure Analysis, 2008, 15(8), 1088. 8 Shi J, Dong H, Wang Q, et al. Journal of Iron and Steel Research, 2000, 12(3), 36 (in Chinese). 时捷, 董瀚, 王琪, 等. 钢铁研究学报, 2000, 12(3), 36. 9 Dong X C, Pan H, Zhao Y, et al. Transactions of Materials and Heat Treatment, 2019, 40(9), 163 (in Chinese). 董现春, 潘辉, 赵阳, 等. 材料热处理学报, 2019, 40(9), 163. 10 Cabrilo A, Geric K. Procedia Structural Integrity, 2018, 13, 2059. 11 Zhou L L. Research on the welding procedure and weld microstructures and properties of high strength steel thick plate welded by laser welding with filling wire. Master’s Thesis, Jiangsu University of Science and Technology, China, 2014 (in Chinese). 周礼龙. 高强钢厚板激光填丝焊工艺与接头组织性能研究. 硕士学位论文, 江苏科技大学, 2014. 12 Ramirez J E. Welding Journal, 2008, 87(3), 65. 13 Guo W, Li L, Dong S Y, et al. Optics & Lasers in Engineering, 2017, 91, 1. 14 Zhang N, Dong X C, Pan H, et al. Transactions of the China Welding Institution, 2015, 36(5), 93 (in Chinese). 张楠, 董现春, 潘辉, 等. 焊接学报, 2015, 36(5), 93. 15 Sun Q, Di H S, Li J C, et al. Materials Science & Engineering A, 2016, 669, 150. 16 Gao Z. Microstructure control and application of high strength armor protective steel plate AP500. Master’s Thesis, Northeastern University, China, 2020 (in Chinese). 郜峥. 高强度装甲防护钢板AP500组织性能控制与应用. 硕士学位论文, 东北大学, 2020. 17 Xu L Y, Bai Y J, Han Y D, et al. Transactions of the China Welding Institution, 2022, 43(3), 1(in Chinese). 徐连勇, 白玉洁, 韩永典, 等. 焊接学报, 2022, 43(3), 1. 18 Lee J H, Park S H, Kwon H S, et al. Materials & Design, 2014, 64, 559. 19 Jiao S J, Wang G F, Jia Y L, et al. Transactions of the China Welding Institution, 2022, 43(3), 93 (in Chinese). 焦帅杰, 王国佛, 贾玉力, 等. 焊接学报, 2022, 43(3), 93. 20 Peng X N, Peng Y, Peng X K, et al. Journal of Mechanical Enginee-ring, 2017, 53(18), 106 (in Chinese). 彭杏娜, 彭云, 彭先宽, 等. 机械工程学报, 2017, 53(18), 106.