X80钢焊接热影响区的二次热循环组织脆化  

Micro-structure Brittleness of Heat Affected Zone after the Second Thermal Cycle for X80 Pipeline Steel

作　　者：占焕校[1] 王勇[1] 吕统全[1] 

机构地区：[1]中国石油大学(华东)机电工程学院

出　　处：《压力容器》2008年第2期9-12,共4页Pressure Vessel Technology

摘　　要：针对X80钢的多道焊接过程,采用热模拟技术研究了不同的二次热循环峰值温度对焊接热影响区粗晶区组织和低温冲击韧性的影响。试验结果表明,经过一次热循环峰温1300℃、二次峰温800℃作用后,晶粒粗大,韧性显著下降,发生严重脆化;而经过二次热循环峰温650,950,1200℃作用,则晶粒细化,获得韧窝状断口形貌。800℃的组织脆化现象与晶粒粗化以及最快沉淀温度附近第二相粒子的大量偏析和聚集有关。With regard to multi - pass welding processes, the micro - structures and properties of the coarse - grain of heat - affected zones affected by the peak temperatures of the second thermal cycle were studied with thermal simulation technique. The experimental results indicated, when the heat - affected zone subjected to a thermal cycle peak temperature of 1300 ℃ first, then re -cooled from 800 ℃, the grains are coarsen and toughness value dropped severely, while the fine grain and dimple fracture appearance can obtained after the second thermal cycle with 1200 ℃ of the peak temperature. The brittleness of micro- structure is related with coarse grain and multitude second phase particles which segregated and congregated around the critical point of fastest precipitation temperature.

关 键 词：焊接 脆化 热循环 管线钢 船舶 

分 类 号：TG406[金属学及工艺—焊接]