高强度钢激光焊接的材料机理研究
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摘要
随着汽车工业的蓬勃发展,以及汽车轻量化的大趋势,优质高强度钢的使用成为了潮流。激光焊接是汽车工业中主要的连接方式之一,解决高强度钢激光焊接的工艺问题具有重要的意义。本文针对CP和DP系列汽车用高强度钢,研究了激光焊接工艺对焊缝成形性,接头组织和力学性能的影响。
选取1.8mm厚DP600钢板和2.8mm厚CP800钢板,分别采用四种不同的激光焊接工艺进行焊接试验,结果表明DP600钢激光焊接线能量增加3.5%,焊缝的上宽度从2.02mm增加到2.48mm,而下宽度从1.13mm减小到1.06mm,而形状因子σ减少了21.8%,焊缝倒梯形上宽下窄的趋势更明显。CP800钢激光焊接线能量增加了7.3%,焊缝的上下宽度都在增加,而形状因子σ增加了16.3%。从焊缝形状上来看,随着线能量的增大,焊缝的倒梯形有向矩形转变的趋势。激光焊接后的样品进行组织观察,结果表明DP600钢中焊缝中间主要是板条状马氏体组织,在热影响区有马氏体,铁素体和残余奥氏体生成。在CP800钢的焊缝中主要形成板条状马氏体以及板条之间的残余奥氏体组织,其中马氏体晶粒尺寸约为20-30μm,同时在焊缝中发现了孪晶马氏体。在热影响区中主要有铁素体,马氏体,贝氏体和残余奥氏体组织生成,热影响区细晶区的晶粒尺寸约为3-5μm,粗晶区晶粒尺寸约为约为15-23μm。测试焊接后的样品的显微硬度,从母材到热影响区再到焊缝区,DP和CP钢激光焊接后样品显微硬度逐渐提高。DP钢激光焊接后焊缝区的显微硬度大约为母材硬度的1.5-1.9倍。CP 800钢激光焊接后焊缝区硬度大约为母材硬度的1.4-1.5倍。DP600和CP800钢采用四种不同的激光焊接工艺,结果表明材料表面成形质量很好,熔合的很整齐,焊缝比较美观,而且没有发现气孔,裂纹等焊接缺陷。
High strength steel (HSS) becomes more and more popular in the automobile production, because the lightweight is always important for the energy consumption and the circumstance protection. Its weld process is required to be more accurate and higher efficient so as to meet the demand of the volume-produce in automobile industry. Laser welding, being an effective method to join the HSS sheets, is very suitable for such application. In this dissertation, two grades of the high strength steel, DP600 and CP800, are selected for the laser welding. The weldments have been investigated in terms of geometry, defects, and the microstructure in the weld and the thermal effect zone. Some relationships have been established between the laser welding parameters and the weldments.
Based on these experiments, the up-width of the weld in DP600 steel increases from 2.02mm to 2.48mm and the down-width of the weld decreases from 1.13mm to 1.06mm when the heat input of the laser-welding improves 3.5%. However, the shape factorσdecreases 21.8%. The up-width and the down-width of the weld in CP800 steel increase and the shape factorσalso increases 16.3% when the heat input of the laser-welding improves 7.3%. The shape of the weld has the tendency to change from inverted trapezoid to rectangle with the increasing of the linear energy in laser welding. The microstructures of the weldments were observed after welding, and the results show that the structures of the weld in the DP600 steel samples are mainly composed of Martensite. And Ferrite, Austenite and Martensite are also observed in the heat affected zone (HAZ). Martensite and retained Austenite which is formed between lath Martensite are observed in the weld of the CP800 steel sheets, and the grain size of the weld is in the range of 20 and 30μm. Twin Martensite is also found in the weld of the samples. The structures of the HAZ consist of Ferrite, Bainite, Martensite and retained Austenite. The grain size of the FG HAZ is in the range of 3 and 5μm and the size of CG HAZ is in the range of 15 and 23μm.
The results of the hardness experiments show that the microhardness of the samples increases gradually from the parent metal to the weld in both DP600 and CP800 steel. And the hardness of the weld is half time higher than that of the base metal. We also found that the qualities of the welding joints are excellent. The weldments are beautiful and the defects (pore or crack) do not exist in the joints.
选取1.8mm厚DP600钢板和2.8mm厚CP800钢板,分别采用四种不同的激光焊接工艺进行焊接试验,结果表明DP600钢激光焊接线能量增加3.5%,焊缝的上宽度从2.02mm增加到2.48mm,而下宽度从1.13mm减小到1.06mm,而形状因子σ减少了21.8%,焊缝倒梯形上宽下窄的趋势更明显。CP800钢激光焊接线能量增加了7.3%,焊缝的上下宽度都在增加,而形状因子σ增加了16.3%。从焊缝形状上来看,随着线能量的增大,焊缝的倒梯形有向矩形转变的趋势。激光焊接后的样品进行组织观察,结果表明DP600钢中焊缝中间主要是板条状马氏体组织,在热影响区有马氏体,铁素体和残余奥氏体生成。在CP800钢的焊缝中主要形成板条状马氏体以及板条之间的残余奥氏体组织,其中马氏体晶粒尺寸约为20-30μm,同时在焊缝中发现了孪晶马氏体。在热影响区中主要有铁素体,马氏体,贝氏体和残余奥氏体组织生成,热影响区细晶区的晶粒尺寸约为3-5μm,粗晶区晶粒尺寸约为约为15-23μm。测试焊接后的样品的显微硬度,从母材到热影响区再到焊缝区,DP和CP钢激光焊接后样品显微硬度逐渐提高。DP钢激光焊接后焊缝区的显微硬度大约为母材硬度的1.5-1.9倍。CP 800钢激光焊接后焊缝区硬度大约为母材硬度的1.4-1.5倍。DP600和CP800钢采用四种不同的激光焊接工艺,结果表明材料表面成形质量很好,熔合的很整齐,焊缝比较美观,而且没有发现气孔,裂纹等焊接缺陷。
High strength steel (HSS) becomes more and more popular in the automobile production, because the lightweight is always important for the energy consumption and the circumstance protection. Its weld process is required to be more accurate and higher efficient so as to meet the demand of the volume-produce in automobile industry. Laser welding, being an effective method to join the HSS sheets, is very suitable for such application. In this dissertation, two grades of the high strength steel, DP600 and CP800, are selected for the laser welding. The weldments have been investigated in terms of geometry, defects, and the microstructure in the weld and the thermal effect zone. Some relationships have been established between the laser welding parameters and the weldments.
Based on these experiments, the up-width of the weld in DP600 steel increases from 2.02mm to 2.48mm and the down-width of the weld decreases from 1.13mm to 1.06mm when the heat input of the laser-welding improves 3.5%. However, the shape factorσdecreases 21.8%. The up-width and the down-width of the weld in CP800 steel increase and the shape factorσalso increases 16.3% when the heat input of the laser-welding improves 7.3%. The shape of the weld has the tendency to change from inverted trapezoid to rectangle with the increasing of the linear energy in laser welding. The microstructures of the weldments were observed after welding, and the results show that the structures of the weld in the DP600 steel samples are mainly composed of Martensite. And Ferrite, Austenite and Martensite are also observed in the heat affected zone (HAZ). Martensite and retained Austenite which is formed between lath Martensite are observed in the weld of the CP800 steel sheets, and the grain size of the weld is in the range of 20 and 30μm. Twin Martensite is also found in the weld of the samples. The structures of the HAZ consist of Ferrite, Bainite, Martensite and retained Austenite. The grain size of the FG HAZ is in the range of 3 and 5μm and the size of CG HAZ is in the range of 15 and 23μm.
The results of the hardness experiments show that the microhardness of the samples increases gradually from the parent metal to the weld in both DP600 and CP800 steel. And the hardness of the weld is half time higher than that of the base metal. We also found that the qualities of the welding joints are excellent. The weldments are beautiful and the defects (pore or crack) do not exist in the joints.
引文
[1] http://www.autosteel.org/AM/Template.cfm?Section=ULSAB_AVC1
[2]张梅,高强度和超高强度相变塑性钢的开发和研究,学位论文,2007
[3]潘玲玲,曾顺民.高强度钢作为汽车轻质材料的应用,上海汽车,2005,8,41-43
[4]王利,朱晓东,张丕军,陆匠心,汽车轻量化与先进的高强度钢板,宝钢技术,2003,5,35-95
[5] AHSS GUIDELINES,IISI-Autoco,2004,3
[6]马鸣图,吴宝榕.双相钢-物理和力学冶金[M],北京:冶金工业出版社,1988
[7] Rocha R O, Melo TMF, Pereloma E V ,et al,Microstructural Evolution at the Initial Stages of Continuous Annealing of Cold Rolled Dual-Phase Steel[J],Materials Science and Engineering,2005,A(391):296-304
[8]江海涛,唐荻,米振莉,汽车用先进高强度钢的开发及应用进展,钢铁研究学报,2007,19(8):1-6
[9]戈晓岚,许晓静,汽车用材料的现状与展望,汽车工程,2002,24(4):294-296
[10] Yan B,用于汽车车身面板的新型双相钢,世界钢,2003(5):32-38
[11] Carrie Gordon, James Robin,Gary Rocheleau,Advanced high strength steel outer body panels in Ford Mustang,http://www.autosteel.org,2003
[12]黄晓艳,刘波,超轻型汽车用钢的研究与开发,炼钢,2007,23(2):05-35
[13] ThomasHeller,Dr.BernhardEnd,BertramEhrhardt et al,New High Strength Steels Production,Properties&Applications.40MWSP CONF.PROC:ISS,1998:25-34
[14] Shi MF,Thomas GH,Chen XM, Formability Performance Comparison Between Dual Phase and HSLA Steels.43MWSPCONF.PROC:ISS,2001:165-174
[15] Horvath CD, Fekete J R. Opportunities and Challenges for Increased Usage of Advanced high Strength Steels in Automobile Applications[A].Baker M A,eds.Proceedings of International Conference on Advanced High Strength Sheet Steels for Automotive Applications[C],AIST Golden CO,USA:2004.1-7
[16]唐荻,米振莉,陈雨来,国外新型汽车用钢的技术要求及研究开发现状[J],钢铁,2005,40 (6):1-5
[17]刘其斌,激光加工技术及其应用,北京-冶金工业出版社,2007
[18]吴思,激光的种类及其在印刷领域中的应用,印刷杂志,2002,6:60-63
[19]李景辉,常君,激光焊接,焊管,2004,27(1):59-62
[20]陈彦宾,现代激光焊接技术[M],北京:科学出版社, 2005
[21]刘必利,谢颂京,姚建华,激光焊接技术应用及其发展趋势[J],激光与光电子学进展,2005,42(9):43-46
[22]曹凤国,激光加工技术,北京:科技出版社,2007
[23]丁黎光,吴德林,丁伟,SMT激光再流焊传热中几种效应的研究,激光杂志,2006,27(1):82-83
[24]胡伦骥,刘建华,汤漾平等,宽板激光拼接技术及设备,应用激光,2002,22(2):188～192
[25]姚建华,苏宝蓉,齿轮激光焊接技术与应用.电力机车,2002,25(4):20-21
[26]朱海红,唐霞辉,朱国富,激光焊接技术在粉末冶金材料中的应用.粉末冶金技术,2000,18(2):117-121
[27] Hamill J A. P/M Jioning processes, Material and technology, The international journal of powder metallurgy,1991,27(4):363～371
[28] Wilks J, Wilks E. Properties and Application of Diamond,Oxford: Butterworth-Heinemann Ltd.,1991,224
[29]姚建华,孙东跃,熊缨等,激光焊接超细基胎体金刚石薄壁钻,激光与光电子学进展,2002,19(6):51～54
[30]梅遂生,激光加工在电子工业中的应用,激光与红外,1994,24(1):5～8
[31] Jail K K.Sutureless misrovascular anastomosis using a Nd YAG laser, Microsurg,1980, 1:436
[32] Bochking G,Ghadially F N. Gastric wall anastomosis by laser in rat,Laser Surg and Med,1988,8:578
[33] Baules J E,Rentleu G.Beview of tissue welding applicatin on Neurosurg, Microsurg,1987, 8:242
[34] Lauto A, Dawes J M, Cushway T et al.Laser nerve repair by solid protein band technique, I. Indentification of optimal laser dose, power, and solder surface area [J]. Microsurgery,1998,18:55-59
[35] Menovsky T, Van-den BWM, Beek J F. Effect of CO2 milliwatt laser on peripheral nerves: Part 1. A dose-response study [J],Microsurgery, 1996,17:562-567
[36]刘卫平,王彦刚,章翔等.激光吻合鼠坐骨神经后神经再生及脊髓神经元变化的实验研究[J],中华显微外科杂志,1999,2:53-54
[37]刘铜军,孙东辉,谭毓铨等,激光焊接皮肤切口的临床研究,中华外科杂志,1999,37:408
[38]赵红亮,刘铜军,刘珍,低功率CO2激光焊接胆总管的研究,中华实验外科杂志,2002, 19(5):474
[39] Master G, Berey B, Forman S K. The biomedical effects of laser application. Laser Surg and Med, 1985, 8:31-39
[40]巩水利,汤昱,杜翔等,BT20钛合金CO2激光焊接工艺,焊接,2002,(10):32～35
[41]王家淳,王希蛰,惠松骁.HE130合金激光焊接线能量与焦点位置的研究,中国激光,2003,30(2):179-184
[42]张军,Li-ion电池的激光焊接,中国机械工程,2001,12(5):213-215
[43]陈俐,胡席远,胡伦骥,高强钢的激光焊接性研究,应用激光,2003,23(1):19-52
[44] A.Khersonsky,et al,Advanced Materials & Processes.2000,(4),39-41
[45]张旭东等,应用激光,1999,19,(5),272-274,78
[46]王锬,怎样防止焊接裂纹,北京:机械工业出版社,1987
[47] E.A.Metzbower,et al,Materials Science and Technology 1994,10,(1),56-59
[48] R.H.Phillips,et al,Welding J.,1992,71,(6),201s-208s.
[49] Y.N.Liu,et al,Welding J.,1997,76,(9),342s
[50] U.Draugelates, et al,Schweissen & Schneiden (Welding and Cutting).2000,52,(1), E27-E31
[51] J.Schuster,et al,Schweissen & Schneiden (Welding and Cutting).1999,51,(5), E74～E77,252-257
[52]任芝兰,汽车用高强度钢的激光焊焊接性研究,机械制造,2006,44(497):72-73
[53] L.Creteur,A.I.Koruk,L.Tosal-Martinez,Proc.Int.Conf.on TRIP-aided High Strength Ferrous Alloys,GRIPS,Ghent,Belgium,2002,pp.353-8
[54] H.Bitzer,The Fascinating World of Sheet Metal,Kesler Verlag- druckerei,Bobingen,Germany,1996
[55] G.Sayeh,Laser Welding,Eurolaser Academy,Liverpool,1996
[56]刘汉谊,焊接碳当量计算及公式应用,承钢技术,2007,(1):34-38
[57] I.Hrivnak,Theory of Weldability of Metals and Alloys,Elsevier,London,GB,1992
[58] Metals Handbook,vol.6,Welding and Brazing,2nd Edition,American Society for Metals, Ohio,1974
[59] I.Ito,K.Bessyo,Weldability Formula of High Strength Steels,D oc,IIW-IX-576-68,IIW,Paris,1968
[60] M.Ono,A.Yoshitake,M.Ohmura,Laser Weldability of High Strength Steel Sheets in Fabrication of Tail or Welded Blanks,NKK Technical Review,No.86,2002,pp.13-18
[61] B.A.Gravile,Proc.Int.Conf.,Rome,Italy,1978,pp.85-101
[62]阎启,热轧高强双相钢焊接性研究,焊接,2008(7):5-25
[63]薛海青,浅谈焊缝的形状尺寸与焊缝质量的关系,同煤科技,2007(3),41-42
[64]张文钺,焊接冶金学(基本原理),机械工业出版社,2003
[65]徐祖耀,低碳马氏体的形成及其应用,上海金属,1982,4(4):46-51
[66] G.Krauss,Metall.Trans.A,vol.32A,2001,pp.861-77
[67] E.A.Wilson,ISIJ Int,vol.34,1994,pp.615-30
[2]张梅,高强度和超高强度相变塑性钢的开发和研究,学位论文,2007
[3]潘玲玲,曾顺民.高强度钢作为汽车轻质材料的应用,上海汽车,2005,8,41-43
[4]王利,朱晓东,张丕军,陆匠心,汽车轻量化与先进的高强度钢板,宝钢技术,2003,5,35-95
[5] AHSS GUIDELINES,IISI-Autoco,2004,3
[6]马鸣图,吴宝榕.双相钢-物理和力学冶金[M],北京:冶金工业出版社,1988
[7] Rocha R O, Melo TMF, Pereloma E V ,et al,Microstructural Evolution at the Initial Stages of Continuous Annealing of Cold Rolled Dual-Phase Steel[J],Materials Science and Engineering,2005,A(391):296-304
[8]江海涛,唐荻,米振莉,汽车用先进高强度钢的开发及应用进展,钢铁研究学报,2007,19(8):1-6
[9]戈晓岚,许晓静,汽车用材料的现状与展望,汽车工程,2002,24(4):294-296
[10] Yan B,用于汽车车身面板的新型双相钢,世界钢,2003(5):32-38
[11] Carrie Gordon, James Robin,Gary Rocheleau,Advanced high strength steel outer body panels in Ford Mustang,http://www.autosteel.org,2003
[12]黄晓艳,刘波,超轻型汽车用钢的研究与开发,炼钢,2007,23(2):05-35
[13] ThomasHeller,Dr.BernhardEnd,BertramEhrhardt et al,New High Strength Steels Production,Properties&Applications.40MWSP CONF.PROC:ISS,1998:25-34
[14] Shi MF,Thomas GH,Chen XM, Formability Performance Comparison Between Dual Phase and HSLA Steels.43MWSPCONF.PROC:ISS,2001:165-174
[15] Horvath CD, Fekete J R. Opportunities and Challenges for Increased Usage of Advanced high Strength Steels in Automobile Applications[A].Baker M A,eds.Proceedings of International Conference on Advanced High Strength Sheet Steels for Automotive Applications[C],AIST Golden CO,USA:2004.1-7
[16]唐荻,米振莉,陈雨来,国外新型汽车用钢的技术要求及研究开发现状[J],钢铁,2005,40 (6):1-5
[17]刘其斌,激光加工技术及其应用,北京-冶金工业出版社,2007
[18]吴思,激光的种类及其在印刷领域中的应用,印刷杂志,2002,6:60-63
[19]李景辉,常君,激光焊接,焊管,2004,27(1):59-62
[20]陈彦宾,现代激光焊接技术[M],北京:科学出版社, 2005
[21]刘必利,谢颂京,姚建华,激光焊接技术应用及其发展趋势[J],激光与光电子学进展,2005,42(9):43-46
[22]曹凤国,激光加工技术,北京:科技出版社,2007
[23]丁黎光,吴德林,丁伟,SMT激光再流焊传热中几种效应的研究,激光杂志,2006,27(1):82-83
[24]胡伦骥,刘建华,汤漾平等,宽板激光拼接技术及设备,应用激光,2002,22(2):188～192
[25]姚建华,苏宝蓉,齿轮激光焊接技术与应用.电力机车,2002,25(4):20-21
[26]朱海红,唐霞辉,朱国富,激光焊接技术在粉末冶金材料中的应用.粉末冶金技术,2000,18(2):117-121
[27] Hamill J A. P/M Jioning processes, Material and technology, The international journal of powder metallurgy,1991,27(4):363～371
[28] Wilks J, Wilks E. Properties and Application of Diamond,Oxford: Butterworth-Heinemann Ltd.,1991,224
[29]姚建华,孙东跃,熊缨等,激光焊接超细基胎体金刚石薄壁钻,激光与光电子学进展,2002,19(6):51～54
[30]梅遂生,激光加工在电子工业中的应用,激光与红外,1994,24(1):5～8
[31] Jail K K.Sutureless misrovascular anastomosis using a Nd YAG laser, Microsurg,1980, 1:436
[32] Bochking G,Ghadially F N. Gastric wall anastomosis by laser in rat,Laser Surg and Med,1988,8:578
[33] Baules J E,Rentleu G.Beview of tissue welding applicatin on Neurosurg, Microsurg,1987, 8:242
[34] Lauto A, Dawes J M, Cushway T et al.Laser nerve repair by solid protein band technique, I. Indentification of optimal laser dose, power, and solder surface area [J]. Microsurgery,1998,18:55-59
[35] Menovsky T, Van-den BWM, Beek J F. Effect of CO2 milliwatt laser on peripheral nerves: Part 1. A dose-response study [J],Microsurgery, 1996,17:562-567
[36]刘卫平,王彦刚,章翔等.激光吻合鼠坐骨神经后神经再生及脊髓神经元变化的实验研究[J],中华显微外科杂志,1999,2:53-54
[37]刘铜军,孙东辉,谭毓铨等,激光焊接皮肤切口的临床研究,中华外科杂志,1999,37:408
[38]赵红亮,刘铜军,刘珍,低功率CO2激光焊接胆总管的研究,中华实验外科杂志,2002, 19(5):474
[39] Master G, Berey B, Forman S K. The biomedical effects of laser application. Laser Surg and Med, 1985, 8:31-39
[40]巩水利,汤昱,杜翔等,BT20钛合金CO2激光焊接工艺,焊接,2002,(10):32～35
[41]王家淳,王希蛰,惠松骁.HE130合金激光焊接线能量与焦点位置的研究,中国激光,2003,30(2):179-184
[42]张军,Li-ion电池的激光焊接,中国机械工程,2001,12(5):213-215
[43]陈俐,胡席远,胡伦骥,高强钢的激光焊接性研究,应用激光,2003,23(1):19-52
[44] A.Khersonsky,et al,Advanced Materials & Processes.2000,(4),39-41
[45]张旭东等,应用激光,1999,19,(5),272-274,78
[46]王锬,怎样防止焊接裂纹,北京:机械工业出版社,1987
[47] E.A.Metzbower,et al,Materials Science and Technology 1994,10,(1),56-59
[48] R.H.Phillips,et al,Welding J.,1992,71,(6),201s-208s.
[49] Y.N.Liu,et al,Welding J.,1997,76,(9),342s
[50] U.Draugelates, et al,Schweissen & Schneiden (Welding and Cutting).2000,52,(1), E27-E31
[51] J.Schuster,et al,Schweissen & Schneiden (Welding and Cutting).1999,51,(5), E74～E77,252-257
[52]任芝兰,汽车用高强度钢的激光焊焊接性研究,机械制造,2006,44(497):72-73
[53] L.Creteur,A.I.Koruk,L.Tosal-Martinez,Proc.Int.Conf.on TRIP-aided High Strength Ferrous Alloys,GRIPS,Ghent,Belgium,2002,pp.353-8
[54] H.Bitzer,The Fascinating World of Sheet Metal,Kesler Verlag- druckerei,Bobingen,Germany,1996
[55] G.Sayeh,Laser Welding,Eurolaser Academy,Liverpool,1996
[56]刘汉谊,焊接碳当量计算及公式应用,承钢技术,2007,(1):34-38
[57] I.Hrivnak,Theory of Weldability of Metals and Alloys,Elsevier,London,GB,1992
[58] Metals Handbook,vol.6,Welding and Brazing,2nd Edition,American Society for Metals, Ohio,1974
[59] I.Ito,K.Bessyo,Weldability Formula of High Strength Steels,D oc,IIW-IX-576-68,IIW,Paris,1968
[60] M.Ono,A.Yoshitake,M.Ohmura,Laser Weldability of High Strength Steel Sheets in Fabrication of Tail or Welded Blanks,NKK Technical Review,No.86,2002,pp.13-18
[61] B.A.Gravile,Proc.Int.Conf.,Rome,Italy,1978,pp.85-101
[62]阎启,热轧高强双相钢焊接性研究,焊接,2008(7):5-25
[63]薛海青,浅谈焊缝的形状尺寸与焊缝质量的关系,同煤科技,2007(3),41-42
[64]张文钺,焊接冶金学(基本原理),机械工业出版社,2003
[65]徐祖耀,低碳马氏体的形成及其应用,上海金属,1982,4(4):46-51
[66] G.Krauss,Metall.Trans.A,vol.32A,2001,pp.861-77
[67] E.A.Wilson,ISIJ Int,vol.34,1994,pp.615-30