The contrast of ERW and SAW

(1) due to SAW weld length of about 4 to 5 times that of ERW weld length, its ability to remove flash without process, thus inevitably increases when the medium pipeline caused by friction. Flash inside the ERW weld length is short, can remove, medium flow in the pipe, the pipe wall friction produced relatively smaller spiral seam submerged arc welding steel pipe, the decrease mix oil generated in oil transportation and reduce the friction temperature rise is very good.

(2), according to the results of determination of residual stress in ERW steel pipecircumferential stress in forming of small, is advantageous for a pipe. For SAW welded pipe, due to the weld area is large, a drawing also have pressure, stress in weld than ERW pipe stress state is complex, it is associated with the molding process of spiral welded pipe. Inner surface to play after tensile stress, axial stress of + 450 Mpa, the circumferential stress is + 344 Mpa, which on the inner wall of the weld seam and heat affected zone of a wide range of tensile stress of internal defects of cracking and stress corrosion produced adverse effect.

(3) due to SAW weld length is about high frequency straight seam pipe weld length of 4 to 5 times, the finished pipe weld treatment of anti-corrosion treatment more difficult; ERW steel tube with weld short () compared with the spiral seam steel pipe, steel pipe wall thickness, length, stable, high geometry precision, anticorrosive and easy to assure the quality of the welding assembly.