| 摘要: |
| 对800 MPa超级钢不同焊接热输入作用下HAZ组织和性能进行了研究.结果表明,800 MPa超级钢在焊接热循环作用下HAZ晶粒明显长大,随着焊接热输入的增大,晶粒长大的趋势越显著;HAZ包含有超低碳贝氏体和细小铁素体等组织,过热区组织在焊接热循环的作用下变化明显,是断裂裂纹的发源地;不同焊接热输入下,整个HAZ的硬度与母材相比有所降低,且在靠近母材和靠近熔合线附近存在两个明显的软化区域;随着焊接热输入的增大,焊接接头屈服强度逐渐降低. |
| 关键词: 超级钢 低碳贝氏体 软化区 |
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| 基金项目:东北大学轧制技术及连轧自动化国家重点实验室开放课题基金资助项目(2009010) |
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| Effects of welding heat input on structure and properties of 800 MPa ultra fine grained steel welding joints |
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ZHAO Hongyun1, LIU Jiakun1, LUO Zong'an2, HU Haifeng1, WANG Guodong2
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1.School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China;2.State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110004, China
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| Abstract: |
| The HAZ microstructure and mechanical properties of the 800 MPa grade ultra fine grained steel under different welding heat input were studied. The results showed that HAZ grain of the 800 MPa grade ultra fine grained steel had grown up distinctly under welding thermal cycle, and there was a more obvious growth trend along with the increase of welding heat input. HAZ contained ultra-low carbon bainite and thin ferrite, and the structure of overheated zone changed obvious under the effect of welding heat, which was the birthplace of the fracture cracks. By comparing to that of the base metal, the hardness value of the whole HAZ was decreased, and there were two distinct softened regions under different welding heat input. The yield strength of the welded joints was reduced gradually with the increase of welding heat input. |
| Key words: ultra fine grained steel low carbon bainite softened region |
