ITER用316LN激光焊接接头显微组织和力学性能研究
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摘要
以21 mm厚的316LN奥氏体不锈钢板为研究对象,采用双面对称施焊的方式进行激光焊接,并对激光焊接接头的显微组织和力学性能进行了分析。结果表明,采用锁底式打底焊接时,焊缝中的主要缺陷是焊接气孔。减小钝边厚度,采用单面打底焊后,气孔问题得到解决。焊缝区显微组织为单相奥氏体,不同位置的显微组织呈现不同的结晶形态,焊缝中心处的等轴晶粒能有效抑制焊接裂纹的产生。激光焊焊接接头拉伸试样均断裂于母材处,弯曲样件表面未见任何微裂纹,焊接接头展现了良好的抗低温冲击性能。
Taking 21 mm thick 316 LN austenitic stainless steel plate as the research object, the laser welding tests were carried out with double-side symmetry welding, and the microstructure and mechanical properties of the laser welded joints were studied. The results show that when bottom locking welding is used, the main defects of the welding seam are porosity,which are solved by decreasing the root thickness and using the single side bottom welding. The microstructure of the weld zone is single austenite, and the microstructures in different locations show different crystalline forms. The equiaxed grain at the weld center can effectively suppress the production of welding cracks. The tensile specimens of laser welded joints all fracture in base metal, and there is no visible crack on the surface of the bending specimens, which shows that the welded joints has good low temperature impact resistance.
Taking 21 mm thick 316 LN austenitic stainless steel plate as the research object, the laser welding tests were carried out with double-side symmetry welding, and the microstructure and mechanical properties of the laser welded joints were studied. The results show that when bottom locking welding is used, the main defects of the welding seam are porosity,which are solved by decreasing the root thickness and using the single side bottom welding. The microstructure of the weld zone is single austenite, and the microstructures in different locations show different crystalline forms. The equiaxed grain at the weld center can effectively suppress the production of welding cracks. The tensile specimens of laser welded joints all fracture in base metal, and there is no visible crack on the surface of the bending specimens, which shows that the welded joints has good low temperature impact resistance.
引文
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[7]许鸿吉,赵雯雯,王春生,等.1.4003不锈钢与0Cr18Ni9不锈钢焊接接头组织和力学性能[J].焊接技术,2008,37(6):12-14.
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[10]安少云,孙晓燕,马世辉.激光焊焊接速度对1Cr17Ni7钢焊接接头组织和性能的影响[J].焊接技术,2014(3):10-13.
[11]谢琦,王希东,张晓华,等.关于焊接工艺评定中弯曲试验的体会[J].焊接,2005(1):33-34.
[2]Mitchell N,Bauer P,Bessette D,et al.Status of the ITER magnets[J].Fusion Engineering and Design,2009,84(2-6):113-121.
[3]Fang C,Song Y T,Wu W Y,et al.Thermal analysis of laser welding for ITER correction coil case[J].Fusion Engineering and Design,2015,100:357-363.
[4]Fang C,Song Y T,Wei J,et al.Microstructure characteristics of the laser welded joint of ITER correction coil sub case[J].Fusion Engineering and Design,2015,98-99:1960-1963.
[5]Xin J J,Fang C,Song Y T,et al.Microstructure and Mechanical Properties of ITER Correction Coil Case Material[J].IEEETransactions on Applied Superconductivity,2017,27(6):1-7.
[6]Jijun Xin,Fang C,Song Y T,et al.Effect of post weld heat treatment on the microstructure and mechanical properties of ITER-grade 316LN austenitic stainless steel weldments[J].Cryogenics,2017,83:1-7.
[7]许鸿吉,赵雯雯,王春生,等.1.4003不锈钢与0Cr18Ni9不锈钢焊接接头组织和力学性能[J].焊接技术,2008,37(6):12-14.
[8]杜坤,张丽芳.激光熔化焊技术的应用及焊缝性能研究[J].汽车工艺与材料,2014(5):1-7.
[9]赵琳,塚本进,荒金吾郎,等.大功率光纤激光焊接过程中工艺参数对熔深和气孔的影响[J].中国激光,2013(11):104-108.
[10]安少云,孙晓燕,马世辉.激光焊焊接速度对1Cr17Ni7钢焊接接头组织和性能的影响[J].焊接技术,2014(3):10-13.
[11]谢琦,王希东,张晓华,等.关于焊接工艺评定中弯曲试验的体会[J].焊接,2005(1):33-34.