1. The surface of the plated parts is not clean⑴The surface of the plated parts contains paint, grease, and welding iron; it can be polished or prepared with related solvents for scrubbing.⑵Iron oxide; lack of pickling; continue pickling.2. Pickling and operation:⑴ Under and over pickling. Under-pic

1. Steel pipe piles need to be properly stackedThe stacking site is required to be flat to ensure that large vehicles can enter directly. For the low-lying area of the site, it is necessary to pave road slag or road wood under the supporting point for artificial reinforcement, and it is necessary to

1. Visual inspection.The visual inspection of welded joints is a simple procedure with a wide variety of inspection methods. It is an important part of finished product inspection, mainly to find welding surface defects and dimensional deviations. Generally, the test is carried out by visual observa

First of all, it may be due to the stress of the spiral welded steel pipe. That is, the residual stress and welding stress after the steel pipe is formed.Secondly, due to the presence of hydrogen. If the flux is not dried enough, the preheating temperature is insufficient or the p