R60702锆激光焊接接头焊缝区的显微组织及其在硫酸中的耐蚀性研究  

Investigation on Microstructure of Weld Zone of R60702 Zirconium Laser Welded Joint and Its Corrosion Resistance in Sulfuric Acid

作　　者：白甘雨 贾均红 李宁 杨光 韩松松 BAI Ganyu;JIA Junhong;LI Ning;YANG Guang;HAN Songsong(College of Mechanical and Electrical Engineering,Shaanxi University of Science and Technology,Xi’an 710021,China;School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710048,China;Xi’an United Pressure Vessel Co.,Ltd.,Xi’an 710201,China)

机构地区：[1]陕西科技大学机电工程学院,陕西西安710021 [2]西安理工大学材料科学与工程学院,陕西西安710048 [3]西安优耐特容器制造有限公司,陕西西安710201

出　　处：《材料保护》2024年第1期50-57,共8页Materials Protection

基　　金：国家自然科学基金(52175178;51974243)资助。

摘　　要：为探究不同焊接工艺下(工艺1:激光功率1 600 W,焊接速度1 600 mm/min,线能量60 J/mm,气体流量20 L/min,离焦量0 mm;工艺2:激光功率1 800 W,焊接速度1 200 mm/min,线能量90 J/mm,气体流量20 L/min,离焦量0 mm)R60702激光焊接接头中焊缝区不同组织的耐蚀性,采用金相显微镜(OM)、X射线衍射仪(XRD)、电化学测试仪、扫描电镜(SEM)、三维轮廓仪和能谱(EDS)对其金相组织、物相组成、耐腐蚀性能及机理、腐蚀形貌、腐蚀产物元素组成进行分析。结果表明:2种焊接工艺下的焊缝区呈现出不同的显微组织,工艺1条件下焊缝区为篮网状组织及少量(26.7%)平行板条状魏氏组织的混合,工艺2条件下焊缝区呈现出典型的魏氏组织。在100℃的20%硫酸中浸泡腐蚀72 h后,混合组织焊缝表现为电偶腐蚀,平行板条状魏氏组织焊缝表现为均匀腐蚀,平行板条状魏氏组织焊缝的耐蚀性更优。这是由于混合组织焊缝的显微组织不均匀性形成了电位差,导致氧化膜因电偶腐蚀发生破裂,因此其耐蚀性较差;而平行板条状魏氏组织焊缝的电化学均匀性良好,自腐蚀电位无显著差异,有利于抑制电偶腐蚀。In order to explore the corrosion resistance of different structures in the weld zone of R60702 laser welded joints under different welding processes(Process 1: laser power 1 600 W, welding speed 1 600 mm/min, linear energy 60 J/mm, gas flow 20 L/min, defocus amount 0 mm;Process 2: laser power 1 800 W, welding speed 1 200 mm/min, linear energy 90 J/mm, gas flow 20 L/min, defocus amount 0 mm), metallurgical microscope(OM), X-ray diffractometer(XRD), electrochemical tester, scanning electron microscope(SEM), three-dimensional profilometer and energy spectroscopy(EDS) were used to analyze the metallographic structure, phase composition, corrosion resistance and its mechanism, corrosion morphology and elemental composition of corrosion products. Results showed that the weld zone exhibited different microstructures under two welding processes. Under the condition of process 1, the weld zone was a mixture of basket-like structure and a small amount(26.7%) of parallel lath-like Widmanstatten structure. Under the condition of process 2, the weld area displayed a typical Widmanstatten structure. After being immersed and corroded in 20% sulfuric acid at 100 ℃ for 72 h, the mixed structure welds showed galvanic corrosion, and the parallel lath Widmanstatten structure welds showed uniform corrosion. In addition, the parallel lath Widmanstatten structure welds had better corrosion resistance. The inhomogeneity of the microstructure of the mixed-structure weld created a potential difference, which caused the oxide film to rupture due to galvanic corrosion, and so the mixed structure held the poorer corrosion resistance. On the contrary, the parallel lath Widmanstatten structure weld had good electrochemical uniformity and no significant difference in self-corrosion potential, which was beneficial to inhibit galvanic corrosion.

关 键 词：激光焊接 工业纯锆 组织 耐腐蚀性能 

分 类 号：TG146.414[一般工业技术—材料科学与工程]