ERW steel pipes adopt cold bending forming process combined with 0.6% diameter reduction and sizing technology. Thanks to the stable forming temperature and standardized production process at room temperature, the outer diameter tolerance can be accurately controlled within the range of ±0.05mm. Seamless steel pipes adopt high-temperature hot rolling forming process above 800℃. Affected by the thermal expansion and contraction of materials and roller wear, the outer diameter fluctuation range increases significantly, and the tolerance range is difficult to accurately control.
ERW steel pipes are made of high-precision hot-rolled strip coils. Through continuous cold rolling process, the wall thickness tolerance is ≤0.05mm, and the transverse wall thickness uniformity error is less than 0.05mm/m. Seamless steel pipes are limited by the round billet perforation process, and the wall thickness deviation can reach ±5-10%, especially at the pipe end. Local thickening or thinning is prone to occur.
