Dependence of mechanical properties of the base metal and welded joint of the high strength steel S690QL on elevated temperatures

Abstract

In this paper is analysed behaviour of mechanical properties of the welded joint and base material of high strength steel S690QL at elevated temperatures. The exposure to elevated temperatures could lead to deterioration of mechanical properties of steel as well as to decreasing of load bearing capacity. Since this steels belongs to a group of steels with exquisite mechanical properties, the aim of this work is to show which is the critical temperature when its mechanical properties are going to worsen. For that purpose, an experimental investigation has been carried out. The specimens were taken both from the welded plate and the base material. The welding was performed with GMAW procedure using two types of filler metals with different mechanical properties for root layer and cover ones. The experiment was performed within the temperature range 20°C to 550°C. The obtained results show the difference with respect to several references, including the European standards, steel producers recommendations and some other researches results. Therefore, studying of mechanical properties of this steel at elevated temperatures is of the utmost importance.