A study on mechanical properties of modern rolled structural metal at elevated temperatures

Introduction. The purpose of this work is to obtain experimental data on the numerical dependence between the strength characteristics of the most widely used grades of rolled structural metal products (including those featuring high heat resistance) and a critical increase in temperature. Materials and methods. As the subject of research we used specimens of rolled metal of the following strength classes: С255 (steel St3sp), С345 (steel 09G2S), С390 (steel 14G2), and rolled metal that had high heat resistance properties S355P (steel 06MBF). Small cylindrical specimens of type B, with M10 thread on heads and the working diameter of 4 mm were used to conduct the static tension and compression tests of mechanical properties. The procedure encompassed the heating of the specimens to the pre-set testing temperature at the rate of not more than 10 °C/min, their 15-minute exposure, and testing for static uniaxial tension/compression. Results and discussion. The results of the experimental research on mechanical properties of different widely used grades of rolled structural steel, including heat resistant rolled metal, subjected to the fire impact, are presented in the article. The data are presented in the form of diagrams used to make a quantitative assessment of the effect of elevated temperature on the strength properties of rolled structural metal under the impact of fire. This information can be contributed to the design and operation of structural metal constructions to develop analytical methods of identifying the fire-resistance limits of constructions made of structural metal. Conclusion. The new data on the fire resistance of metal products allow for a more reasonable building design, higher safety and resistance of buildings and structures to the effect of fire. A wider area of application of the whole range of rolled products featuring higher heat resistance will reduce metal consumption and construction costs, boost competitiveness and attractiveness of steel structures and their application in the construction of buildings and structures of various purposes.