adhesion test; condensation chamber test; Hot-dip galvanizing; MAG welding; Zn layer

Hot-dip galvanising is one of the most widely used methods for protecting structural steel against corrosion. This article examines the quality and thickness of the Zn coating on Kosmalt E300T low carbon deep-drawing structural steel Kosmalt E300T MAG-welded. The steel meets the requirement for hot-dip galvanising according to the Sandelin diagram, with a silicon content below the critical amount of 0.03 % wt. In contrast, the welding wire contains a critical amount of 0.9 % wt. silicon, which is unsuitable for hot-dip galvanising. On the basis of this fact and the Sandelin diagram, the Zn coating on the welded joint is expected to have a higher thickness and a different structure compared to the unaffected steel surface. The article evaluates the quality of the Zn coating on the welded joint by adhesion testing and condensation chamber testing. According to the results of the experimental tests, the Zn coating on the welded joint was twice as thick as that on the unaffected steel surface. The Zn coating on the welded joint shows changes in the content of individual phases, good adhesion to the welded joint, and resistance to corrosion. © 2024 Tanger Ltd., Ostrava.

Hot-dip galvanising is one of the most widely used methods for protecting structural steel against corrosion. This article examines the quality and thickness of the Zn coating on Kosmalt E300T low carbon deep-drawing structural steel Kosmalt E300T MAG-welded. The steel meets the requirement for hot-dip galvanising according to the Sandelin diagram, with a silicon content below the critical amount of 0.03 % wt. In contrast, the welding wire contains a critical amount of 0.9 % wt. silicon, which is unsuitable for hot-dip galvanising. On the basis of this fact and the Sandelin diagram, the Zn coating on the welded joint is expected to have a higher thickness and a different structure compared to the unaffected steel surface. The article evaluates the quality of the Zn coating on the welded joint by adhesion testing and condensation chamber testing. According to the results of the experimental tests, the Zn coating on the welded joint was twice as thick as that on the unaffected steel surface. The Zn coating on the welded joint shows changes in the content of individual phases, good adhesion to the welded joint, and resistance to corrosion. © 2024 Tanger Ltd., Ostrava.