Before the pressure pipeline nondestructive testing, visual inspection of welds shall comply with the requirements. Pressure pipe weld appearance and surface quality of welded joints general requirements are as follows: welding should look good shape, width of each side groove edge 2mm overshadowed appropriate. Fillet weld leg height should meet the design requirements, the shape should be smooth transition.


(1) Do not allow cracks, lack of fusion, pores, slag, spatter exist.
(2) The design temperature is below -29 degrees pipes, stainless steel and hardened alloy steel pipes tend to be larger weld surface, without undercut. Other material pipe weld undercut depth should be greater than 0.5mm, continuous undercut length should not exceed 100mm, and both sides of the weld undercut always grow up to 10 percent of the entire length of the weld.
(3) Not be lower than the surface of the weld surface of the pipe. Weld reinforcement and no more than 3mm, (the maximum width of weld joints after groove).
(4) Welded joints the wrong side of the wall thickness should be less than 10% and not more than 2mm.