Discuss the corrosion-induced failure of welds
Thread Content
Applying anti-corrosion coatings to steel structures not only enhances their appearance but also extends the service life of these steel structural components. After some painting projects are completed, upon close inspection, many small cracks can be found in corners, weld areas, and other such places – areas that are easily overlooked. Although it seems unremarkable, it poses serious safety hazards. This is because corners are usually joint areas, and these joints are subjected to tension from the pipes in the steel structure, bearing stress as a result. Once the corrosion protection at these welds fails and corrosion occurs inside, the supporting parts of the entire steel structure become vulnerable, leading to various dangers. In production, issues such as leaks, spills, drips, and even breaks often occur at the welding areas. In mild cases, this leads to system shutdowns and disrupts production; in severe cases, explosions can occur, causing serious losses to production and the economy, as well as potential casualties. The solutions are as follows: 1. First, coat the surface of the steel structure; choose an appropriate coating and strictly control the thickness of the paint film. 2. Second, the metal material must be carefully selected to ensure it has the best possible chemical compatibility with the operating environment. It should also be noted that burrs, cracks, as well as irregular shapes at the surface and root of the weld can be causes of corrosion. To avoid these problems, proper cleaning and surface treatment are very important; the weld must be polished smoothly to eliminate sharp edges. If arc welding or automatic powder welding is used, the slag must be removed after each weld. The surface finish must be uniform and smooth, and it is advisable to oxidize the surface to prevent further corrosion. Passivation can remove surface contaminants and form a new, uniform passivation oxide layer on the surface, thereby protecting the metal from corrosion.
Welds are the weak points in steel structures and are prone to corrosion. Due to the high stresses exerted at corners and welds, improper anti-corrosion treatment can lead to cracks and corrosion, thereby affecting the overall safety of the structure. To prevent weld corrosion, it is necessary to select appropriate coatings, control the thickness of the coating layer, use metal materials that are compatible with the environment, and properly clean and treat the weld surfaces through processes such as grinding, removing slag, and applying oxidation treatments to enhance corrosion resistance. .
Due to the specific requirements of applying anti-corrosion paint at welds, it is difficult to achieve the standard surface treatment requirements. Moreover, the method of application differs from spraying in the prefabrication plant. As a result, corrosion at welds is an inevitable issue, yet it has not been resolved over the years, representing a major challenge in engineering.