某承压蒸汽锅炉检修时发现其烟管端头处出现大量裂纹,采用宏观观察、扫描电镜分析,以及热力计算和结构设计校核对烟管开裂原因进行了分析。结果表明:烟管端头部位温度过高导致热疲劳开裂;锅炉结构存在严重的设计问题,锅炉炉胆长度太短,燃烧器与炉膛实际结构不匹配,造成回燃室和烟管端头位置温度过高。

A large number of cracks appeared at the end of the flue pipe of a pressurized steam boiler. The reasons for the cracking of the flue pipe were analyzed by macroscopic observation, scanning electron microscopy analysis, thermal calculation and structural design check. The results show that the high temperature at the end of the flue tube led to thermal fatigue cracking. There were serious design problems in the boiler structure. The length of the boiler furnace was too short, and the burner did not match the actual structure of the furnace, resulting in high temperature at the end of the combustion chamber and the flue pipe.