Anti-Corrosion Performance of Four Hot Dip Galvanizing Bolts

The hot-dip galvanizing coating can promote the anti-corrosion performance of the bolts in outdoor steel structure engineering. But the anti-corrosion performance cannot match that of the steel due to the centrifugal process. In this paper, the anti-corrosion performance of four kinds of bolts obtained from different company was researched by the neutral salt spray test method. The results show that the anti-corrosion performance of the all four bolts was unsatisfactory. The reasons were studied through testing the thickness of the coating, coating uniformity, surface morphology and elemental composition. The results show that the causes are the lower thickness of the hot-dip coatings, too much defects on the surface of the coatings and the elemental composition impurity.