针对某垃圾发电余热锅炉过热器管子与集箱连接角焊缝部位频繁开裂的问题，对上下集箱间平行直管的受热面结构及管间温差于管子与集箱连接角焊缝部位的热应力进行分析计算。结果表明，对于本算例，当管间温差大于42℃时，连接部位的一次应力＋二次应力已超过相关标准的允许值。综合考虑焊缝形状、焊缝抗疲劳能力等因素，建议将管间温差控制在20℃以下。%Weld seam cracking occurred frequently on a waste heat boiler's superheater header nozzle.Thus, the structure of heating surface of parallel straight tubes between the upper and lower headers was ana-lyzed,and the structure thermal stress caused by temperature difference between the tubes was calculated. When the temperature difference between tubes is higher than 42 ℃,the primary plus secondary stress of connection parts has exceeded the related standards.Considering factors like the weld shape,weld fatigue resistance weakening and others,suggestion that the temperature difference between tubes should be con-trolled below 20 ℃ was put forward.
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