压力容器用508-Ⅲ钢焊接热影响区组织分析

摘要

On Gleeble 1500 thermal simulation test machine, adopting thermal simulation technique to study continuous cooling transformation curve of 508- Ⅲ steel HAZ . Combined with metallographic observation and hardness measurement, it plotted SH-CCT curve of 508-Ⅲ steel, and analyzed structure of weldment HAZ according to the results of cooling transformation curve .The results showed that, in order to obtain perfect HAZ structure, it should adjust welding process parameter, reduce cooling speed at the key temperature range of phase transition(800～500 ℃). In actual welding, it should keep cooling speed at 1～5 ℃/s (t85 is 60～300 s ), 13％～27％ ferrite + 73％～81％ granular bainite can be obtained.%采用焊接热模拟技术,在Gleeble1500热模拟试验机上对508-Ⅲ钢的焊接热影响区进行了连续冷却转变曲线(SH-CCT)的研究,结合金相观察和硬度测定,绘制了508-Ⅲ钢的SH-CCT曲线.根据冷却转变曲线试验结果对现场提供的焊接件热影响区进行了组织分析.通过分析得出,为了获得较为理想的热影响区组织,应当通过调整焊接工艺参数,减小重点相变温度段(800～500℃)的冷却速度,实际焊接时应保证以1～5℃Is(t<,8/5>为60～300 s)的速度冷却,可以得到组织为13%～27%的铁素体+73%～81%的粒状贝氏体.