Straight seam steel pipe is fully analyzed. The application of submerged arc welded straight seam steel pipe in the industry is obvious to all. Its wide application must be due to its unique advantages. However, as a successful business, we should fully understand this product, and analyze the advantages and disadvantages of hot-rolled steel pipe.
Hot-rolled 20# straight seam steel pipe Disadvantages: [1] Residual stress caused by uneven cooling. Residual stress is the internal self-phase equilibrium stress without external force. Hot-rolled steel of various cross-sections has such residual stress. The larger the section size of the section steel, the larger the residual stress. Although the residual stress is self-phase-balanced, it still has some influence on the performance of the steel component under external force. For example, deformation, stability and fatigue resistance may occur. Unfavorable effect; [2] After welding, the non-metallic inclusions inside the straight seam steel pipe are pressed into thin slices, and delamination occurs. The layering makes the performance of the 20# straight seam steel pipe pulled in the thickness direction greatly deteriorated, and It is possible that the interlaminar tear occurs when the weld shrinks. The local strain induced by the weld shrinkage often reaches several times the yield point strain, which is much larger than the strain caused by the load.
Advantages of submerged arc welding straight seam steel pipe: it can destroy the casting structure of steel ingot, refine the grain of steel, and eliminate the defects of microstructure, so that the steel structure is compact and the mechanical properties are improved. This improvement is mainly reflected in the rolling. In the direction, the 20# straight seam steel pipe is no longer an isotropic body to some extent; the bubbles formed during casting, cracks and looseness can also be welded under the action of high temperature and pressure.
