Corrosion Behavior of Welded Steel Pipe

　　The corrosion resistance of welded steel pipe containing Ni is strong in acidic environment. In the environment containing sulfuric acid or hydrochloric acid, the higher the content of Ni in welded steel pipe, the stronger the corrosion resistance. In general environment, only adding Cr into welded steel pipe can prevent corrosion. The poor edge condition of steel strip is another important reason for the wrong edge. The influence of mass flow rate, heat flux density and structural parameters (the ratio of helical curvature diameter to welded pipe diameter, Dc/D) on the heat transfer coefficient of saturated bubbling in vertical helical tubes.

　　In the production of API 5l x70 Q345 Carbon Welded Steel Pipe, staggered edges occur from time to time, and there are many influencing factors. In production practice, the steel pipe is often degraded due to the excessive errors of dry staggered edges. Therefore, it is necessary to analyze the causes and preventive measures of the misalignment of spiral steel pipe.

　　Because the shape and dimension accuracy of the non-trimmed steel strip head and tail are poor, it is easy to cause the steel strip to bend hard and cause staggered edges when butting. The range of simulation parameters: vertical pipe: diameter D = lOmm, length L = 660mm; three kinds of vertical welded steel pipe: diameter D = 10mm, the ratio of curvature diameter of welded steel pipe to helical diameter changes respectively Dc/D = 15, 20, 25, helical pitch Pt = 20mm, length L = 503mm, L = 660mm, L = 817MM. 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.