摘要
研究了不同线能量输入对EH420钢焊接热影响区组织及低温冲击性能的影响。利用真空感应炉和TMCP轧制工艺制备EH420试验钢板,利用Gleeble-3800型动态热模拟试验机对试样进行焊接热模拟试验,利用拉伸试验机和冲击试验机对母材和焊后模拟试样进行力学性能检测,利用光学显微镜对试样进行金相观察。结果表明:采用Ti-Mg复合脱氧的氧化物冶金技术和TMCP轧制工艺制备的钢板具有良好的大线能量焊接性能;Ti-Mg-O粒子促使焊接热影响区生成大量的针状铁素体,从而改善其低温冲击性能;随着线能量的增加,原奥氏体尺寸增大,晶界铁素体逐渐增多,魏氏体含量先增加后减少,魏氏体晶粒尺寸增大, HAZ低温冲击吸收功呈下降趋势。
The effects of different heat input on the microstructure and low temperature impact properties of the heat affected zone(HAZ) of EH420 steel were studied. The test steel plate was manufactureed by vacuum induction furnace and TMCP rolling process. The welding thermal simulation tests were carried out by using the Gleeble-3800 dynamic thermal simulation test machine. The mechanical properties of the base metal and post-weld simulated samples were tested by tensile testing machine and impact tester. The metallographic observation was carried out by using optical microscope. The results show that the steel plate prepared by using Ti-Mg compound deoxidization and TMCP rolling process has excellent welding performance of high heat input welding. In the heat affected zone, a large number of acicular ferrite is formed because of Ti-Mg-O particles, which improves the low temperature impact properties. With the increase of heat input, the original austenite size increases, the ferrite at grain boundary increases gradually, the Widmanstaten content first increases and then decreases, the size of the Widmanstatten increases. Therefore, the low temperature impact absorbing energy of the HAZ decreases.
引文
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