Advantages of LSAW tube
It can destroy the casting structure of ingot, refine the grain size of steel, eliminate the defects of microstructure, make the steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, which makes the LSAW pipe to some extent no longer isotropic; pouring bubbles, cracks and loose layers can also be welded under high temperature and pressure.
LSAW tube
Defects of LSAW pipeline
1. Residual stress caused by uneven cooling. Residual stress is the internal self-equilibrium stress without external force. This residual stress exists in all hot rolled steel sections. The larger the general section size, the greater the residual stress. Although the residual stress is self-balanced, steel members may have adverse effects under external forces or certain impact forces, such as deformation, stability, fatigue and so on.


2. After welding, the non-metallic inclusions in the sawtooth pipe are pressed into thin sheets and layers, which makes the performance of the straight seam pipe layered in the thickness direction, and may occur when the seam shrinks and the interlayer is torn. The local strain caused by weld shrinkage is usually several times that of yield point strain, which is much larger than that caused by load.