Effect of aging treatment on microstructure and mechanical properties of deposited metal of ER347 stainless steel

时效处理对ER347不锈钢熔敷金属微观组织和力学性能的影响 Effect of aging treatment on microstructure and mechanical properties of deposited metal of ER347 stainless steel 郝龙宇 HAO Longyu 1 first-author 田得喜 TIAN Dexi 2 徐锴 XU Kai 1 李瑞 LI Rui 2 吕晓春 LV Xiaochun 1 安洪亮 AN Hongliang 1 郭枭 GUO Xiao 1 哈尔滨焊接研究院有限公司 哈尔滨焊接研究院有限公司 Beijing Xinfeng Aerospace Equipment Co.,Ltd. Beijing Xinfeng Aerospace Equipment Co.,Ltd. 北京新风航天装备有限公司  北京新风航天装备有限公司  Harbin Welding Institute Limited Company Harbin Welding Institute Limited Company 研究了ER347熔敷金属在750 ℃长期时效过程中σ相的析出行为及其对力学性能的影响。结果显示,ER347熔敷金属的铁素体含量、硬度及冲击韧性与时效时间存在密切关联。ER347熔敷金属在750 ℃时效时,随时效时间的延长,σ相析出增多,硬度增大,铁素体含量和韧性则降低。ER347熔敷金属焊态冲击韧性良好,时效处理后,韧性下降,其脆化的根本原因在于δ-铁素体分解形成了硬脆σ相,显著降低了ER347熔敷金属韧性。（σ+γ 2 ）结构内部存在大量的高能σ/γ 2 和δ/σ/γ 2 非共格界面,且σ相自身硬脆,易作为潜在裂纹源,在高应变速率下,发生脆性开裂并迅速扩展,导致熔敷金属韧性降低。 The precipitation behavior of σ phase and its effect on mechanical properties of ER347 deposited metal during long-term aging at 750 ℃ are studied. The results show that the ferrite content,hardness and impact toughness of ER347 deposited metal are closely related to the aging time. When ER347 deposited metal is aged at 750 ℃,with the extension of aging time, σ phase precipitation increases,hardness increases,while the ferrite content and toughness decrease. ER347 deposited metal has good as-welded impact toughness,but the toughness decreases after aging treatment. The root cause of the embrittlement is that δ-ferrite decomposes to form a hard and brittle σ phase,which significantly reduces the toughness of ER347 deposited metal. There are a large number of high-energy σ/γ2 and δ/σ/γ2 incoherent interface inside（σ +γ2） structure,and the σphase itself is hard and brittle, which is easy to act as a potential crack source,under high strain rate,brittle cracking occurs and spreads rapidly, resulting in the deposited metal toughness decreased. ER347熔敷金属 σ相 力学性能 时效处理 ER347 deposited metal σ phase mechanical properties aging treatment TG44;TL34;TG156.92 2022-03-08 5 51