DETERMINATION OF THE FRACTURE TOUGHNESS CHARACTERISTICS OF S355JR STEEL

The article presents the results of tests carried out on S355JR steel of ferrite-pearlite and ferrite-bainite microstructures.The strength properties and fracture toughness were determined.The critical value of fracture toughness was determined at the moment of crack initiation by measuring of the stretch zone width, and in the moment of reaching a subcritical crack growth of 0.2 mm.Determination of fracture toughness characteristics was carried out in accordance with the procedures of ISO and ASTM standards.