Shortcomings of Hot-rolled LSAW Steel Pipe

[1] Non-uniform cooling caused by residual stress. Residual stress is no external force in the internal self-phase equilibrium stress, a variety of cross-section of hot-rolled steel have such residual stress, the general section size of the larger steel, residual stress The residual stress is self-phase equilibrium, but it has certain influence on the performance of the steel member under external force, such as deformation, stability, anti-fatigue and so on.

[2] After welding, the non-metallic inclusions in lsaw steel pipe are compressed into thin slices, which causes the delamination phenomenon, which greatly deteriorates the tensile properties of the straight seam steel pipe along the thickness direction, The local strain induced by weld shrinkage often reaches several times of the yield point strain, which is much greater than the strain caused by the load.