[1] [1] Li Helin. Developing pulse and prospect of oil and gas transmission Pipe[J]. Welded Pipe and Tube,2004,27(6):111

[2] [2] Mi Qiuzhan,Yu Yingzi,Wang Lesheng. Welding technology of long-distance oil and gas pipeline[J]. Welding Technology,2006,35(1):46

[3] [3] P. L. Moore,D. S. Howse,E. R. Wallach. Microstructures and properties of laser/arc hybrid welds and autogenous laser welds in pipeline steels[J]. Science and Technology of Welding and Joining,2004,9(4 ):314-322

[4] [4] S. Webster,J. K. Kristensen,D. Petring. Joining of thick section steels using hybrid laser welding[J]. Ironmaking & Steelmaking,2008,35(7):496-504

[5] [5] Yang Xichen,Wang Yu,Ying Chaolong et al.. Microstructure and Properties of High Power Laser Welding of Ship Steel Plate[J]. Chinese J. Lasers.,2007,34(6):866-870

[6] [6] Chen Jimin,Xu Xiangyang,Xiao Rongshi. Laser Modern Manufacture Technology[M]. Beijing:National defense Industry Press,2007,8283,108

[7] [7] Chen Yanbin. Modern Laser Welding Technology[M]. Beijing:Science Press,2005,23

[8] [8] Wang Hong,Shi Yaowu,Gong Shuili et al.. Effect of assist gas flow on the gas shielding during laserdeep penetration welding[J]. Journal of Materials Processing Technology,2007,184(13):379-385

[9] [9] M. Hamadou,R. Fabbro,F. Coste et al.. Experimental study of CO2 laser welding inside a grooveApplication to high thickness laser welding[J]. Journal of Laser Applications,2005,17(8):178-182

[10] [10] K. Y. Benyounis,A. G. Olabi,M. S. J. Hashmi. Effect of laser welding parameters on the heat input and weld bead profile[J]. Journal of Materials Processing Technology,2005,164-165:978-985

[11] [11] K. Manonmani,N. Murugan,G. Buvanasekaran. Effects of process parameters on the bead geometry of laser beam butt welded stainless steel sheets[J]. The International Journal of Advanced Manufacturing Technology,2007,32(11-12):1125-1133

[12] [12] Li Yanxiang,Wu Aiping. Principle of materials processing[M]. Beijing:Tsinghua University Press,2005,119-123

[13] [13] Zhang Wenyue. Welding metallurgy[M]. China Machine Press,1996,185-188

[14] [14] M. Kocak,J. dos Santos,S. Riekehr.Trends in laser beam welding technology and fracture assessment of weld joints[J]. Science and Technology of Welding and Joining,2001,6( 6):347-350

[15] [15] Zhang Xiaoli,Zhuang Chuanjing,Ji Lingkang et al.. Structure Feature and Strength-Toughness of High Grade Pipeline Steels[J]. Special Steel,2006,27(6):27-29