Small-diameter thick-walled seamless steel pipes refer to pipes with an outer diameter less than 377mm and an outer diameter-to-wall thickness ratio less than 20. Currently, the smallest diameter available is 3mm, with wall thickness as thin as 1mm.
Formula for the weight of small-diameter thick-walled seamless steel tubes: (Outer Diameter - Wall Thickness) * Wall Thickness * 0.02466 = kg/m (weight per meter)
Small diameter thick-walled seamless steel tubes are commonly used in the double-sided submerged arc welding production process. The product undergoes multiple processes including bending, jointing, internal welding, external welding, straightening, and flatheading to meet API standard requirements. Large diameter thick-walled steel pipes are predominantly applied in large-scale steel structure construction, serving as the main supporting section, such as bridge pile driving, offshore pile driving, and high-rise building pile driving.
Primarily used for oil geological drilling pipes, cracking pipes for petrochemical use, boiler pipes, bearing pipes, and high-precision structural pipes for automotive, tractor, and aviation applications.