论文部分内容阅读
采用热模拟技术模拟研究不同热输入对X80管线钢焊接粗晶区组织与性能的影响。结果表明,焊接热影响粗晶区组织主要由板条状和粒状贝氏体组成,随着热输入的增加,焊接热影响粗晶区的板条贝氏体数量逐渐减少,粒状贝氏体数量逐渐增加,彼此交错分布。当热输入E=20 kJ/cm时,焊接热影响粗晶区晶粒虽有所长大,但板条贝氏体和粒状贝氏体交叉混合分布,表现出较好的冲击性能。通过分析得出,采用焊前预热和小热输入的焊接工艺既可以减少高温停留时间tH,防止晶粒粗化,又可以相应的提高800℃到500℃的停留时间t8/5,给组织相变提供适当的时间,以达到改善X80管线钢手工焊工艺。
The influence of different heat input on the microstructure and properties of X80 pipeline steel in the coarsening zone was simulated by thermal simulation. The results show that the microstructure of coarse grains in the heat affected zone mainly consists of lath and granular bainite. With the increase of heat input, the number of lath bainite in the coarse grain zone decreases gradually. The amount of granular bainite Gradually increase, staggered with each other. When the heat input E = 20 kJ / cm, although the grain size of coarse grains in the weld heat affected grows, the lath bainite and granular bainite are mixed and distributed, showing good impact properties. Through the analysis, it can be concluded that the welding process with preheating and small heat input can reduce the high temperature residence time (tH), prevent the grain coarsening and raise the residence time (t8 / 5) from 800 ℃ to 500 ℃, Phase change to provide the appropriate time to improve the X80 pipeline manual welding process.