2 the size and surface quality of steel pipe shall meet the following requirements:1) the new steel pipe should have quality certificate, quality inspection report; steel surface should be flat and smooth, no cracks, scarring, delamination, dislocation, bend, burr, indentation and scratch depth of steel pipe; allowable deviation table item allowable deviation inspection tool 1 welded steel pipe size (mm) diameter 48 wall 3.5 -0.5 thick 2 vernier caliper at two ends of the steel tube shear diagonal deviation 1.7 corner ruler feeler, the outer surface of the steel pipe 3 corrosion depth is less than or equal to 0.50 bar 4 vernier caliper end bend L = 1.5m = 5, 5 pole bending steel ruler 3m