Seamless steel tubes with different cross-sectional shapes can be divided into tubular and special-shaped ones. Because around the same conditions, the largest area of a circle with a circular tube can carry more fluid. In addition, the circular section is subjected to internal or external radial pressure, and the force is uniform.  Therefore, the vast majority of pipelines are pipelines. However, there are some limitations. Under the conditions of plane bending, pipe and square, bending strength of large seamless steel pipe, skeleton of some agricultural machinery, square and rectangular pipes popular in steel and wood furniture. Seamless steel tubes with different mechanical properties.


Seamless hot rolled coil is used as raw material for cold rolling after pickling and rust removal. The rolling hardness of finished product is high. The rolling hardness deformation strength, hardness increase and toughness plasticity index decrease due to continuous cold working hardening. Therefore, stamping performance will deteriorate and can only be used for simple modification of components. Rolled hard volume can be used as raw material for hot dip galvanizing equipment, because the hot dip galvanizing production line has annealing line. Rolling hard coils generally weigh 6 to 13.5 tons and have a coil inner diameter of 610 mm. Cold-rolled sheet is usually used. Coils should be evaluated by continuous annealing (CAPL unit) or intermittent annealing and rolling to eliminate work hardening stress and meet the corresponding mechanical performance standards.