高钢级ERW石油套管用钢焊接热影响区组织和性能研究

The Study on Microstructure and Mechanical Properties at Welding HAZ of High Grade ERW Petroleum Casing Steel

采用Gleeble焊接热模拟技术并结合金相-硬度法,对试制的高钢级ERW石油套管用钢焊接热影响区组织和性能进行研究。结果表明:随着碳当量的增加,试制钢的淬透性显著增强,同时焊接热影响区冷裂纹敏感性增大;试制钢焊接热影响区的组织存在显著差异,在焊接热影响区的过热粗晶区、热-机械交界区、正火区等3个区域中,过热粗晶区的组织粗大并出现魏氏组织和马氏体淬硬组织。

By means of Gleeble welding simulation technology in combination with metallographic hardness method,the research is performed on the microstructure and mechanical properties at welding HAZ of trial-produced high grade ERW petroleum casing steel.The results show that with the increase of carbon equivalent value,the hardenability of trial-produced steel is greatly improved,and the cold cracking susceptibility at welding HAZ of the same steel is increased.Significant difference exists at the welding HAZ microstructure,i.e.,among the three zones of overheated coarse grain zone,thermo-mechanical cohesive zone and normalized zone at welding HAZ,the microstructure at overheated coarse grain zone is coarsened,and Widmannstatten structure and martensite hardened structure appear at the same zone.