The result shows that the ring weld has weld defects and under alternating stress it will crack,which will finally cause breaking of the urea synthetic tower.

Effect of simulated welding parameters on pipe girth weld residual stresses;

In order know the size and the distribution of residual stresses of mill welding seam,this paper uses blind-hole method to test the girth welds between round plate and the cylinder body of the mill produced by CBMI CONSTRUCTION CO.

The mechanical properties testing and metallography testing of girth welded joints were carried out.

Experimental results show that the acoustic emission technique can effectively detect heavy weld active flaws and the accurate size and location of flaws can be measured by the ultrasonic phased array technique.