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谭锦红, 张新平, 曹姗姗, 王鹏, 曾庆瑞, 陈斌. U71Mn钢闪光-摩擦复合焊接头组织性能[J]. 焊接学报. DOI: 10.12073/j.hjxb.20240117002
引用本文: 谭锦红, 张新平, 曹姗姗, 王鹏, 曾庆瑞, 陈斌. U71Mn钢闪光-摩擦复合焊接头组织性能[J]. 焊接学报. DOI: 10.12073/j.hjxb.20240117002
TAN Jinhong, ZHANG Xinping, CAO Shanshan, WANG Peng, ZENG Qingrui, CHEN Bin. Investigation on Microstructure and Properties of Rail U71Mn Steel Joints by Flash-Friction hybrid Welding[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION. DOI: 10.12073/j.hjxb.20240117002
Citation: TAN Jinhong, ZHANG Xinping, CAO Shanshan, WANG Peng, ZENG Qingrui, CHEN Bin. Investigation on Microstructure and Properties of Rail U71Mn Steel Joints by Flash-Friction hybrid Welding[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION. DOI: 10.12073/j.hjxb.20240117002

U71Mn钢闪光-摩擦复合焊接头组织性能

Investigation on Microstructure and Properties of Rail U71Mn Steel Joints by Flash-Friction hybrid Welding

  • 摘要: 闪光对焊在焊接钢轨时易在焊缝中心产生氧化夹杂缺陷以及软化层,严重降低了接头力学性能,针对上述问题,开发了闪光-摩擦复合焊, 并基于不同的顶锻距离对U71Mn钢进行了焊接工艺研究.结果表明,焊接接头成型良好,接头组织主要分为母材区(base material, BM)、热机影响区(thermo-mechanically affected Zone, TMAZ)、热影响区(heat-affected Zone, HAZ)以及焊核区(weld zone, WZ),其中,在焊接热输入以及摩擦顶锻的作用下,TMAZ及WZ晶粒发生细化,同时,在线性摩擦的作用下,WZ未出现明显的高铁素体含量的软化层组织.接头显微硬度呈现M形分布,最高硬度位于TMAZ,接头抗拉强度随顶锻距离的增加呈现先上升后下降趋势,最高抗拉强度约为900.3 MPa,达到母材的89.2%,其断裂形式为准解理断裂.

     

    Abstract: Flash butt welding, when applied to rail welding, is prone to the formation of oxidized inclusion defects and softening layers at the weld, significantly impairing the mechanical properties of the joints. To address these issues, this study proposed a novel flash-friction hybrid welding(F-FHW) method and explored the welding process for U71Mn steel based on varying upsetting distances. The results revealed that the welded joint was well formed and the joint structure was mainly divided into base metal area (BM), thermomechanical affected zone (TMAZ), heat affected zone (HAZ) and weld zone (WZ). Notably, the grains in the TMAZ and WZ were refined under the combined influence of welding heat input and friction upsetting. Additionally, under the action of linear friction, the softening layer with elevated ferrite was not appeared in the WZ. The microhardness of the joints displayed an M-shaped distribution, with the highest hardness located at TMAZ. The tensile strength of the joint initially increased and then discreased as the upsetting distance extends. The maximum tensile strength of the joints was approximately 900.3MPa, achieving 89.2% of the BM, and its fracture form is quasi-cleavage fracture.

     

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