Q370q桥梁用钢焊接热影响区组织性能的研究

Study on Microstructure and Properties in HAZ of the Q370q High Strength Bridge Steel

采用Gleeble2000热模拟实验机测定出首钢研制开发的Q370q桥梁用钢焊接连续冷却转变曲线（SH—CCT图），获得焊接工艺特征参数tg/s从3．5s到2500s范围内的组织变化规律。利用热模拟技术进行了Q370q桥梁用钢热影响区组织、性能的模拟研究，结果表明：粗晶热影响区存在着脆化现象，随着焊接热输入的增加，奥氏体晶粒粗化，脆化加剧。

The continuous cooling transformation curve of Q370q Bridge Steel in welding is measured by Gleeble 2000 thermal simulated machine, as well as, the transformation rule of the microstructures with ts/5 from 3.5 second to 2 500 second is obtained. Besides, the microstructures and properties of Q370q Bridge Steel in heat affect zone are studied in use of thermal simulation technique. The study result indicates that the coarse grain heat affect zone （CGHAZ） exists brittle phenomenon, and as the welding heat input increasing, the austenite grain become coarsening and the brittle of CGHAZ is aggravated