Fatigue Strength of Marked Steel Components

Abstract

Steel components have to be identifiable and traceable during the whole manufacturing chain. The choice of the identification method is not specified consistently in international rules and standards. In the European standard for the execution of steel structures EN 1090-2 it is specified that the use of durable marks may not result in producing damages and that hard stamped marks are only permitted for steel grades up to S355 and only in areas where no effect on the fatigue life is expected.In terms of durability and liability, markings should be resistant against particular manufacturing processes such as sandblasting, hot-dip galvanizing or coating. In detail, these methods are hard stamping, scribing, plasma marking and needling.Nowadays the machinery manufacturers have developed machines in which the marking process is automatically integrated in the manufacturing process. However, the effect of the installed notch due to the marking process on the fatigue strength of the components has not been investigated in detail yet. As a result a classification of the notched details in the European detail categories of EN 1993-1-9 is in principle not possible.For these reasons the influence of durable marking methods on the fatigue strength of steel components needs to be clarified by experimental fatigue tests and numerical calculations which are actually performed at the Institute for Metal and Lightweight Structures of University of Duisburg-Essen. The tests should determine the influence of several identification methods on the fatigue strength of structural steel details. Within the investigations the different surface conditions hard stamped, scribed, plasma marked and needled are considered. The fatigue tests are carried out considering three different steel plate thicknesses 15mm, 25mm and 40mm and two different steel grades S355J2 and S460N.