换热管与管板先胀后焊工艺焊接方案优化

Optimization of the“Expansion before Welding”Scheme for Heat Exchange Tubes and Tube Plates

在换热器制造过程中,换热管与管板的连接是最为关键的工序之一,换热管胀焊并用的连接方式应用较多,目前,先焊后胀制造次序的选用最为广泛,但是对于先胀后焊焊接方法的介绍和讨论较少。本文基于某合成氨项目中变换气锅炉给水预热器,对该设备换热管与管板先胀后焊制造过程中管头焊缝产生气孔缺陷的原因进行了分析,提出了优化的焊接方法。通过模拟实验和产品返修结果验证了优化方法的可行性,可为先胀后焊换热器的制造提供借鉴和参考。

The connection between heat exchange tube and tube plate is one of the most critical processes in heat exchanger manufacturing.The connection method featuring heat exchange tube expansion&welding is widely used.At present,the manufacturing sequence of“welding before expansion”is the most extensively selected,while the“expansion before welding”method is less introduced and discussed.In this paper,the cause of cavity on the pipe head welds through“expansion before welding”of the heat exchange tubes and tube plates of the feed water preheater to the shift-gas boiler in a certain synthetic ammonia project is analyzed,and the optimized welding method is put forward.The feasibility of this optimization method is verified via simulation experiments and product rechecking results,providing reference for the manufacture of heat exchangers through“expansion before welding”.