Use of a carbon-manganese steel for structural members of high strength and toughness by simple heat treatment

摘要

1. Use of a steel having 0.3 to 0.6 % carbon 0.2 to 0.6 % silicon 0.55 to 2.5 % manganese 0.05 to 0.2 % vanadium 0 to 0.3 % zirconium 0 to 0.2 % niobium 0 to 0.5 % chromium 0 to 0.5 % nickel 0 to 0.5 % copper 0 to 0.3 % molybdenum 0.01 to 0.05 % sulphur 0 to 0.1 % aluminium 0.0005 to 0.005 % boron 0 to 0.4 % nitrogen less than 0.0003 % hydrogen the rest iron and melting-induced impurities, as a material for components with a cross section from about 40 cm**2 which, after heat deformation by rolling, forging or pressing, or an annealing process at final moulding temperatures up to about 1 000 degrees C or annealing temperatures up to about 1 000 degrees C, and subsequent cooling in still or moving air, if necessary after controlled cooling, have a ferritic-pearlitic structure with approximately 5 to 20% ferrite, the rest pearlite and an interval- or 0.2 border of at least 580 N/nm**2 and an impact energy measured by ISO-U tests of at least 25 J.