Hot‐dip galvanizing of high‐strength hot‐finished hollow sections

Abstract

The galvanizability of high‐strength, hot‐finished hollow sections was investigated as part of a test programme. Here, square sections made of steel grades ranging from 355 to 620 MPa were galvanized using two processes: a classic, quasi‐rare zinc melt and a zinc‐5 % aluminium alloy. To determine the influence of galvanizing on the material properties, samples were taken from the galvanized specimens, tensile tests and Charpy‐V‐tests were performed on them, and the results were compared with those in the ungalvanized initial state. Furthermore, we investigated the optical and microstructural characteristics of the zinc coatings, as well as possible cracking due to liquid metal embrittlement (LME). The results show that the two galvanizing processes used in the test programme produce no negative effect, but rather tend to have a positive effect on the mechanical properties of the steels tested. In all cases, stable zinc coatings are formed that exhibit the expected characteristics. Cracking as a result of LME could not be detected.