多道间断焊T型接头的数值模拟

Numerical Simulation of Multi-pass Discontinuous Welding of T-joint

不停输带压开孔操作的关键在于在线焊接 ,由于作业时不停止介质的传输 ,管道设备内部介质的压力、温度等特性会影响操作的安全性。在有内部介质流动的设备上进行在线焊接 ,局部高温是引起烧穿的主要原因 ,本文将间断焊技术引入在线焊接 ,对其温度场和应力场进行了数值模拟 ,结果表明 ,采用间断焊可以有效降低焊接时的温度 ,而且残余应力数值与连续焊相当。

In-service welding is an important operation of hot tapping. There is no need to stop transportation. However, the properties of medium such as pressure and temperature etc. will affect the safety of operation. The localized high temperature is the major factor that causes burn-through. In this paper, a technique of discontinuous welding was used for in-service welding. The temperature and stress field were simulated by FEM. It can be concluded that the elevated temperatures could be reduced effectively by discontinuous welding. The values of residual stresses are close to those of continuous welding. However, due to frequent arc starting, the quality is difficult to guarantee.