Mechanical properties of structural steels at elevated temperatures and after cooling down

Experimental research program has been carried out during the years 1994-2001 in the Laboratory of Steel Structures at Helsinki University of Technology in order to investigate mechanical properties of several structural steels at elevated temperatures by using mainly transient state tensile test method. The aim is to produce accurate material data for the use in different structural analyses. The main test results are public and they are available for other researchers. In this paper the experimental test results for the mechanical properties of the studied steel grades S350GD+Z, S355 and S460M at fire temperatures are presented with a short description of the testing facilities. A test series was also carried out for cold-formed material taken from rectangular hollow sections of structural steel S355J2H and these test results are also given in this report. The mechanical properties of structural steel after cooling down have also been shortly examined and these test results are given in this report. The test results were used to determine the temperature dependencies of the mechanical properties, i.e. yield strength, modulus of elasticity and thermal elongation, of the studied steel material at temperatures up to 950°C. The test results are compared with the material model for steel according to Eurocode 3: Part 1.2