Untersuchungen zum zeitabhängigen mechanischen Materialverhalten von S460 im Brandfall

Analysis of the time-dependent mechanical behaviour of S460 in case of fire.

The knowledge of the mechanical behaviour of structural steel at elevated temperatures is essential for structural fire design. In Eurocode 3 Part 1-2 [1] stress-strain relationships up to 1200 °C are provided which are uniform for steel grades from S235 to S460. However, there is no sufficient experimental data base for the high strength fine grain structural steel S460. Creep strain developing in the course of a fire can, according to the design concept of [1], not be considered explicitly. This article presents the results of a research project dealing with the time-dependent mechanical material behaviour of high strength fine grain structural steel S460 in case of fire. The stress-strain relationships at elevated temperatures were derived from the results of extensive transient test series. Subsequently the creep behaviour of S460 under fire conditions was analysed and an empirical creep law was developed which allows for the accurate consideration of creep strain in the stress-strain relationships. By means of metallographic investigations it was possible to identify the influence of the chemical composition and the production process on the high temperature resistance.