余热锅炉汽包开裂原因分析  

Analysis of Cracking Causes of Waste Heat Boiler Steam Drum

作　　者：林寅 LIN Yin

机构地区：[1]福建省锅炉压力容器检验研究院漳州分院,漳州市363000

出　　处：《化工装备技术》2024年第6期50-53,共4页Chemical Equipment Technology

摘　　要：若焊接时坡口形式和焊接规范不合理,加上使用过程中操作管理不当,将会对锅炉安全运行产生重大影响。以某台余热锅炉汽包内表面开裂为例,通过资料审查、宏观检查、无损检测和理化检验等方法对汽包内表面开裂机理进行了分析和研究。结果表明,汽包内表面发生开裂的主要原因为对接焊口坡口钝边较大,为了获得较大熔深,采用大电流和小焊速的焊接工艺,导致焊接接头过热,产生魏氏组织,从而增加了裂纹敏感性。在使用过程中,由于除氧器及省煤器失效,导致给水温度过低,同时,锅炉水容积大幅减小,给水频率显著增加,裂纹敏感性较强的焊缝及其热影响区在给水冷冲击的循环作用下,产生疲劳裂纹。If the groove form and welding specification selection are not reasonable during welding,coupled with improper operation and management during use,it will have a serious impact on the safe operation of the boiler.Taking the cracking of the inner surface of a waste heat boiler steam drum as an example,the mechanism of cracking on the inner surface of the steam drum was analyzed and studied through methods such as data review,macroscopic inspection,non-destructive testing,and physical and chemical testing.The results showed that the main reason for the cracking of the inner surface of the steam drum was the excessive blunt edge of the butt weld groove.In order to obtain a larger penetration depth,a welding process with high current and low welding speed was adopted,resulting in overheating of the welding joint and the formation of Widmanstätten structure,thereby increasing the sensitivity of cracks.During use,the failure of the deaerator and economizer resulted in a low feedwater temperature.At the same time,the boiler water volume significantly decreased,the feedwater frequency significantly increased,and the weld seams and their heat affected zones with strong crack sensitivity developed fatigue cracks under the cyclic action of water cooling impact.

关 键 词：余热锅炉 魏氏组织 冷冲击 疲劳裂纹 

分 类 号：TK223[动力工程及工程热物理—动力机械及工程]