Effect of Microstructure of Welded Joints HG785D on Impact Toughness


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The microstructure and impact toughness of joints of HG785D high strength steel welded by metal active gas shielded arc welding (80%Ar+20%CO2) was observed and analyzed. The result showed that the microstructure of weld seam was mainly composed of acicular ferrite, the impact energy of which was better. While the microstructure of HAZ with large size bainite and M-A island. Using the method of EBSD, it's also found that the effective grain size of weld seam was similar with fine grain HAZ. However the proportion of high-angle grain boundary in weld seam was much larger than that of HAZ. As a result, it could arrest propagating cracks and enhance the toughness.



Edited by:

Hun Guo, Taiyong Wang, Dunwen Zuo, Zijing Wang, Jun Li and Ji Xu




Q. Zhang et al., "Effect of Microstructure of Welded Joints HG785D on Impact Toughness", Key Engineering Materials, Vol. 693, pp. 740-746, 2016

Online since:

May 2016




* - Corresponding Author

[1] Hajro Ismar, Zijah Burzic, Nenad Kapor. Experimental investigation of high-strength structural steel welds. Journal of Mechanical Engineering [J]. 2012, 58(6): 422-428.

DOI: https://doi.org/10.5545/sv-jme.2011.281

[2] Jiang Qiuyue, Jia Kunning. Structure transformation of HAZ for high strength weathering steel. Heat Treatment of Metals [J]. 2013, 38(3): 28-31.

[3] Morito S, Saito H, Ogawa T, et al. Effect of austenite grain size on the morphology and crystallography of lath martensite in low carbon steel[J]. ISIJ Int, 2005, 45(1): 91-94.

DOI: https://doi.org/10.2355/isijinternational.45.91

[4] Dhua S K, Mukerjee D, Sarma D S, Weldability an microstructure aspects of shielded metal arc welded HSLA steel plates[J]. ISIJ Int, 2005, 42(3): 290-298.

DOI: https://doi.org/10.2355/isijinternational.42.290

[5] WANG Jianfeng, LI Guangqiang, XIAO Aida, DENG Shen. Study on Microstructure and Properties of Welded Joints of 600 MPa Grade Ti-microalloyed High Strength Steel. Casting·Forging·Welding[J]. 2010, 39(19): 10-15.

[6] Neves J, Loureiro A. Fracture toughness of welds effect of brittle zones and strength mis-mat ch[ J] . Journal of Material Processing Technology, 2004, (153- 154) : 537- 543.

DOI: https://doi.org/10.1016/j.jmatprotec.2004.04.120

[7] FENG Wei, CAO Rui, PENG Yun, DU Wansheng, TIAN Zhiling, CHEN Jianhong. Microstructure and mecharical properties of HAZ of 980 MPa high strength steel joints. Transactions of the China Welding Institution[J]. 2009, 30(7): 18-21.

[8] WU changzhong, CHEN huaining, LEI qinghua, WANG ulin. Microstructure and toughness of HAZ of 1000 MPa high strength steel joints. Transactions of the China Welding Institution[J]. 2011, 32(5): 97-101.