X100级管线钢焊接粗晶区微观组织预测

Microstructure Forecast of X100 Pipeline Steel Welding Coarse Grain Zone

采用Gleeble3500热-力学模拟试验机,研究了在不同焊接热循环条件下,X100级管线钢焊接粗晶区组织形态的变化规律。实验结果表明,X100级管线钢焊接粗晶区组织主要有粗大的粒状贝氏体、贝氏体铁素体和马氏体。当焊后冷却速度低于2℃/s时,焊接粗晶区组织为粒状贝氏体;当焊后冷却速度为2～5℃/s时,组织为贝氏体铁素体;当焊后冷却速度高于5℃/s时,粗晶区开始出现马氏体组织。

Using the Gleeble thermal simulation machine, under different welding thermal cycles, the variation of the microstructure in coarse grained zone of X100 pipeline steel was researched. The results illustrate that there are mainly three types of microstructure in coarse grain zone of X100 pipeline steel, coarse granular Bainite, Bainite ferrite and Martensite. When cooling rate after welding is smaller than 2℃/s, granular Bainite is obtained in coarse grain zone;when cooling rate is between 2℃/s and 5℃/s, Bainite ferrite is more likely to generate; when cooling rate is higher than 5℃/s, Martensite is appeared in coarse grain zone.