Corrosion resistance of welded steel pipe

　　In the production of T-shaped welded steel pipe, misalignment often occurs, and there are many influencing factors. In the production practice, the steel pipe is often degraded due to the out of tolerance of dry misalignment. Therefore, it is necessary to analyze the causes and preventive measures of spiral steel pipe misalignment.

　　Due to the poor shape and dimensional accuracy of the head and tail of the uncut steel strip, it is easy to cause the hard bending of the steel strip during butt joint and cause the misalignment. Simulation parameters range: vertical pipe: diameter d = lomm, length L = 660mm; Three kinds of vertical T-shaped welded steel pipe: diameter d = 10 mm, the ratio of curvature diameter and spiral diameter of T-shaped welded steel pipe is DC / D = 15,20,25, spiral pitch Pt = 20 mm, pipe length L = 503 mm, l = 660 mm, l = 817 mm. Mass flow g = 200 ~ 400kg / (m'2 · s), heat flux q = 5 ~ 15kw / m'2, saturation pressure P, saturation = 0.414880mpa, saturation temperature T, saturation = 283.15k.