Advantages and disadvantages of LSAW pipeline
Date:2018-05-24 View:316 Tag:Advantages and disadvantages of LSAW pipeline
Advantages of LSAW pipes
It can destroy the casting structure of steel ingots, refine the grain of steel, eliminate the defects of structure, make the steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel pipe is no longer isotropic to some extent; the dumping bubble, the crack and the loose stratum can also be welded at high temperature and high pressure.
1, the residual stress caused by unequal cooling. The residual stress is the internal self balancing stress in the absence of external force. All cross-sections of hot rolled steel have such residual stresses. The greater the size of the general section, the greater the residual stress. Although the residual stress is self balanced, the steel structure may have adverse effects on the external force, such as deformation, stability, fatigue and so on.
2, after welding, the non-metallic inclusions in the steel pipe are pressed into thin slices and stratified to reduce the thickness of the straight pipe, and the interlayer tear may occur when the weld is contracted. The local strain induced by welding shrinkage usually reaches several times the yield point strain, far greater than the strain induced by load.