不锈钢激光-MAG复合焊接头微区性能研究
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摘要
激光复合焊可用于不锈钢焊接,但激光复合焊接头热影响区小,组织变化梯度大.研究接头微区性能可以确定接头薄弱环节,为焊接接头的工艺评定和断裂分析提供理论依据.为此,本文对4 mm厚SUS301L-HT不锈钢进行激光-MAG复合焊接,采用维氏硬度、微型剪切和微拉伸等试验,研究了焊接接头焊缝、热影响区及母材的微区力学性能,并结合金相、断口扫描等分析了各微区力学性能的差异.结果表明:焊缝区域组织主要为柱状奥氏体树枝晶+少量的δ铁素体;母材的剪切强度和抗拉强度最高,分别为560和1 066 MPa,其次为复合焊接头热影响区,焊缝区域最差,接头硬度分布规律与各微区强度变化趋势一致;运用数学方法,得出了接头微拉伸强度与微型剪切强度、硬度之间关系的经验公式.接头各微区剪切断口和拉伸断口SEM分析呈现典型的韧性断裂特征.
The laser hybrid welding can be used for stainless steel welding,but the laser hybrid welded joint has a small heat affected zone and a large microstructural change gradient. The study of joint micro-area performance can determine the weak link of the joint,provide a theoretical basis for the process assessment and fracture analysis of welded joints. The laser-MAG hybrid welding was applied to weld the stainless steel with 4 mm thickness. The properties of the welded metal,heat affect zone and base metal were researched by hardness test,micro-tensile test and micro-shear test. The differences of micro-zone properties were analyzed using metallography and SEM. The results indicate that the microstructure of the welded metal is columnar austenite dendrites and small amount of δ-ferrite. The base metal had the highest shear strength of 560 MPa and tensile strength of 1 066 MPa,followed by heat-affected zone and welded metal. The hardness distribution of welded joint was consistent with the trend of micro-intensity. By mathematical method,the experienced formula of micro-tensile strength and micro-shear strength as well as micro-tensile strength and hardness were obtained respectively. It was found by analyzing shear and tensile fracture of joint,fracture morphology of the micro-zone was a dimple pattern with feature of ductile fracture.
The laser hybrid welding can be used for stainless steel welding,but the laser hybrid welded joint has a small heat affected zone and a large microstructural change gradient. The study of joint micro-area performance can determine the weak link of the joint,provide a theoretical basis for the process assessment and fracture analysis of welded joints. The laser-MAG hybrid welding was applied to weld the stainless steel with 4 mm thickness. The properties of the welded metal,heat affect zone and base metal were researched by hardness test,micro-tensile test and micro-shear test. The differences of micro-zone properties were analyzed using metallography and SEM. The results indicate that the microstructure of the welded metal is columnar austenite dendrites and small amount of δ-ferrite. The base metal had the highest shear strength of 560 MPa and tensile strength of 1 066 MPa,followed by heat-affected zone and welded metal. The hardness distribution of welded joint was consistent with the trend of micro-intensity. By mathematical method,the experienced formula of micro-tensile strength and micro-shear strength as well as micro-tensile strength and hardness were obtained respectively. It was found by analyzing shear and tensile fracture of joint,fracture morphology of the micro-zone was a dimple pattern with feature of ductile fracture.
引文
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[13]唐舵,王春明,田曼,等. SUS301L-HT不锈钢激光焊接与MIG焊接对比试验研究[J].中国激光,2015,42(7):90-97.TANG Duo,WANG Chunming,TIAN Man,et al.Contrasting study on quality of SUS301L-HT jointsin fiber laser welding and MIG welding[J]. Chinese Journal of Lasers,2015,42(7):90-97.
[14]龚兴华,唐舵,朱伟,等. 2 mm不锈钢SUS301LHT光纤激光对接工艺研究[J].造船技术,2016(1):69-74.GONG Xing,TANG Duo,ZHU Wei,et al. Study on the process of 2 mm stainless steel sus301L-HT fiber laser butt welding[J]. Marine Technology, 2016(1):69-74.
[15]李洪梅,孙大千,王文权,等.奥氏体不锈钢丝激光焊接头的组织与力学性能[J].焊接学报,2009,30(6):71-74.LI Hongmei,SUN Daqian,WANG Wenquan,et al.Microstructure and mechanical properties of austenite stainless steel wire joints welded by laser[J].Transactions of the China Welding Institution,2009,30(6):71-74.
[16]杨晓益,陈辉,王秋影,等. A7N01P-T4铝合金激光-MIG复合焊接头微区性能[J].焊接学报,2016,37(8):114-118.YANG Xiaoyi,CHEN Hui,WANG Qiuying,et al.Micro-zone performance of laser-MIG hybrid welded A7N01P-T4 Al alloy joints[J]. Transactions of the China Welding Institution,2016,37(8):114-118.
[2] HAYASHI M. Trends in laser arc combination welding methods[J]. Welding International,2002,16(2):94-98.DOI:10. 1080/09507110209549498
[3] ABE N,HAYASHI M. Trend of laser arc combination welding method[J]. Quarterly Journal of the Japan Welding Society,2001,70(4):389-393.
[4]李刚卿,韩晓辉.不锈钢车体的焊接工艺及发展[J].机车车辆工艺,2004(1):1-4.LI Gangqing,HAN Xiaohui. The welding technology for stainless steel car body and its development[J].Locomotive&Rolling Stock Technology,2004(1):1-4.
[5]刘龙玺,钟元木,马传平,等.地铁用SUS301L奥氏体不锈钢激光焊接头残余应力研究[J].热加工工艺,2013,42(13):186-188.LIU Longxi,ZHONG Yuanmu,MA Chuanping,et al.Research on laser welding joint residual stress of SUS301L austenitic stainless steel for subway[J].Hot Working Technology,2013,42(13):186-188.
[6]张兰.我国不锈钢焊接工艺研究现状及进展[J].山西冶金,2007,30(2):1-5.ZHANG Lian. Present research status and development of welding technology for stainless steel in china[J]. Shanxi Metallurgy,2007,30(2):1-5.
[7]张亮,方洪渊,王林森,等. A7N01铝合金焊接接头的不均匀特性[J].焊接学报,2012,33(11):97-100.ZHANG Liang,FANG Hongyuan,WANG Linsen,etal. Inhomogeneity for A7N01 aluminum alloy welded joint[J]. Transactions of the China Welding Institution,2012,33(11):97-100.
[8]周丽霞,王士元,DORN L.应用微型剪切试验评定焊接接头的力学性能[J].西安交通大学学报,1993(5):41-48.ZHOU Lixia,WANG Shiyuan,DORM L. Evaluation of mechanical properties for welded joint by microshear test[J]. Journal of Xian Jiaotong University,1993(5):41-48.
[9]汤忠斌,徐绯,许泽建,等.焊缝结构微区材料力学性能研究[J].机械强度,2010,32(1):58-63.TANG Zhongbin,XU Fei,XU Zejian,et al. Research on mechanical properties of micro zones of welding line[J]. Journal of Mechanical Strength,2010,32(1):58-63.
[10]雷斌隆,王元良.微型剪切试验法及基在焊接技术中的应用[J].西南交通大学学报,1990,25(1):14-20.LEI Binlong,WANG Yuanliang. Micro shear test and its use in welding technique[J]. Journal of Southwest Jiaotong University,1990,25(1):14-20.
[11]雷斌隆,王元良.焊接接头微型剪切试验[J].西南交通大学学报,1992,27(1):7-11.LEI Binlong,WANG Yuanliang. Micro shear testing of welded joints[J]. Journal of Southwest Jiaotong University,1992,27(1):7-11.
[12] BUNAZIV I,AKSELSEN OM,SALMINEN A,et al.Fiber laser-MIG hybrid welding of 5 mm 5083aluminum alloy[J]. Mater Process Technol,2016,233:107-114.DOI:10. 1016/j. jmatprotec. 2016. 02. 018.
[13]唐舵,王春明,田曼,等. SUS301L-HT不锈钢激光焊接与MIG焊接对比试验研究[J].中国激光,2015,42(7):90-97.TANG Duo,WANG Chunming,TIAN Man,et al.Contrasting study on quality of SUS301L-HT jointsin fiber laser welding and MIG welding[J]. Chinese Journal of Lasers,2015,42(7):90-97.
[14]龚兴华,唐舵,朱伟,等. 2 mm不锈钢SUS301LHT光纤激光对接工艺研究[J].造船技术,2016(1):69-74.GONG Xing,TANG Duo,ZHU Wei,et al. Study on the process of 2 mm stainless steel sus301L-HT fiber laser butt welding[J]. Marine Technology, 2016(1):69-74.
[15]李洪梅,孙大千,王文权,等.奥氏体不锈钢丝激光焊接头的组织与力学性能[J].焊接学报,2009,30(6):71-74.LI Hongmei,SUN Daqian,WANG Wenquan,et al.Microstructure and mechanical properties of austenite stainless steel wire joints welded by laser[J].Transactions of the China Welding Institution,2009,30(6):71-74.
[16]杨晓益,陈辉,王秋影,等. A7N01P-T4铝合金激光-MIG复合焊接头微区性能[J].焊接学报,2016,37(8):114-118.YANG Xiaoyi,CHEN Hui,WANG Qiuying,et al.Micro-zone performance of laser-MIG hybrid welded A7N01P-T4 Al alloy joints[J]. Transactions of the China Welding Institution,2016,37(8):114-118.