基于高效焊接的EQ51海工钢焊接接头组织调控研究

Research in Microstructure Controlling of Welded Joint with Offshore Steel EQ51 Based on High-Efficiency Welding

通过常规力学检测获得了高效焊接条件下EQ51海工钢熔敷金属及匹配不同板材焊后的力学性能。利用SEM和EBSD等方法分析了焊缝、再热粗晶区、临界再热粗晶区和亚热影响区的组织形貌。结果表明，母材碳和锰的含量偏高和焊接融合比是造成焊缝韧性偏低的原因。通过降低碳和锰的含量、降低镍含量和提高钼含量的递进式母材成分设计进行组织调控，有效抑制了热影响区中M／A岛的析出，将熔合线平均冲击吸收功从14J提高到62J，满足大于33J的焊接要求。

Considering the difference of cooling process between thick plant and thin plant, thewelding mechanical properties of high-efficiency welding on offshore steel EQS1 have been investigated for improving the welding structure security in this paper. The microstructure in four areas marked HF, CGHAZ, ICGHAZ and SCGHAZ has been analyzed by SEM and EBSD. The results show that the higher component of C-Mn in base metal and penetration ratio are the primary causes which make the toughness decreased. Though graded composition design from decreasing C- Mn, decreasing Ni, to increasing Mo, the ideal microstructure is obtained, which makes the M/A precipitates depressed in HAZ. The average impact energy in fusion-line can be raised from 14 J to 62 J, which is sufficient the deadline of 33 J.