600MW超临界锅炉中隔墙开裂原因分析

Cause Analysis on Mid-board Tube Fracture of 600 MW Supercritical Boiler

针对600MW锅炉安装现场反复出现12Cr1MoV中隔墙开裂的现象,对开裂管段进行宏观、金相、电镜、化学、力学等分析,认为焊接和热处理过程中产生的焊接应力在强拘束条件下诱发鳍片焊接缺陷扩展是导致中隔墙管材开裂的原因,提出扩大加热范围和加长鳍片割开长度避免裂纹缺陷的建议。

For repeated fracture on 12Cr1MoV Mid Board tube of 600 MW supercritical boiler in the course of installation,a series of analysis on the crack is made through macroscopic,observation,metallographic examination,SEM,chemical and mechanical properties test.It is regarded that the high stress of the tube producing by welding and heat treatment induce crack initiation and propagation on the defects of fins weld under the rigid restraint.Suggestions have been made that heat zone must be enlarged and the length of fins cutting must extend when thick wall tubes welding under the condition of strong constraint.