• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2025, Vol. 61 ›› Issue (20): 72-80.doi: 10.3901/JME.2025.20.072

• 材料科学与工程 • 上一篇    

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304不锈钢局部干法水下激光焊接组织及性能研究

赵永庆1, 张清华1,2, 田义丰3, 陈英杰3, 孙清洁1,2, 刘一搏1,2, 李星帅3   

  1. 1. 哈尔滨工业大学(威海)山东省特种焊接技术重点实验室 威海 264209;
    2. 哈尔滨工业大学材料结构精密焊接与连接全国重点实验室 哈尔滨 150001;
    3. 中广核核电运营有限公司 深圳 518000
  • 收稿日期:2024-12-25 修回日期:2025-06-30 发布日期:2025-12-03
  • 作者简介:赵永庆,男,1998年出生。主要研究方向为水下激光焊接。E-mail:zyq1356251416@163.com
    孙清洁(通信作者),男,1980年出生,博士,教授,博士研究生导师。主要研究方向为焊接过程控制及高效焊接。E-mail:qjsun@hit.edu.cn
  • 基金资助:
    国家自然科学基金(52275320,52175299)和中国广核集团-哈尔滨工业大学先进核能与新能源研究院自主探索预研(202210)资助项目。

Research on the Structure and Performance of Local Dry Underwater Laser Welding of 304 Stainless Steel

ZHAO Yongqing1, ZHANG Qinghua1,2, TIAN Yifeng3, CHEN Yingjie3, SUN Qingjie1,2, LIU Yibo1,2, LI Xingshuai3   

  1. 1. Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209;
    2. State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin 150001;
    3. China Nuclear Power Operations Co., Ltd., Shenzhen 518000
  • Received:2024-12-25 Revised:2025-06-30 Published:2025-12-03

摘要: 水下焊接过程会受到多种因素的影响,包括水的侵入、冷却作用以及对焊接接头微观结构和性能的影响,为探讨水下环境对304不锈钢局部干法激光焊接接头性能的影响,利用自主设计的双层气体排水装置,进行了50 mm水深304不锈钢的局部干法水下激光焊接试验,对激光功率3.0 kW,焊接速度0.8 m/min,内层气流量25 L/min时的水下接头和陆上接头进行研究。结果表明,在焊接过程中水的侵入会造成焊缝表面部分氧化,水的冷却作用降低了焊接过程峰值温度和冷却速度,使形核率和过冷度变大,促进晶粒细化,焊缝凝固模式发生转变,凝固后的组织为奥氏体和部分铁素体,水下接头平均硬度大于陆上接头,抗拉强度可达到陆上接头的97%;从断裂形貌和机制来看,二者为韧性断裂,都为微孔聚集型,但是水下接头有部分脆性特征;从腐蚀行为来看,水的冷却作用加重了Cr、Ni元素的偏析,降低了水下接头的耐腐蚀性。

关键词: 304不锈钢, 局部干法, 激光焊接

Abstract: The underwater welding process is influenced by various factors, including water intrusion, cooling effects, and their impact on the microstructure and properties of the weld joint. To investigate the effects of the underwater environment on the performance of 304 stainless steel partial dry laser welding joints, experiments were conducted using a self-designed double-layer gas drainage device for local dry underwater laser welding of 304 stainless steel at a water depth of 50 mm. The underwater and terrestrial welds were studied under laser power of 3.0 kW, welding speed of 0.8 m/min, and inner gas flow rate of 25 L/min. The results indicated that water intrusion during the welding process caused partial oxidation of the weld seam surface. The cooling effect of water reduced the peak temperature and cooling rate during the welding process, leading to an increase in nucleation rate and undercooling, promoting grain refinement, and altering the solidification mode, resulting in a microstructure consisting of austenite and partial ferrite after solidification. The average hardness of the underwater joint was higher than that of the terrestrial joint, and the tensile strength could reach 97% of the terrestrial joint. Fracture morphology and mechanism analysis revealed that both joints exhibited ductile fracture with micro-pore aggregation, while the underwater joint exhibited some brittle characteristics. Moreover, the cooling effect of water exacerbated the segregation of Cr and Ni elements, reducing the corrosion resistance of the underwater joint.

Key words: 304 stainless steel, local dry method, laser welding

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