Fire-resistant welding steel in the form of hollow profiles, supports or molded steel contains alloying additions of silicon, manganese, aluminum, molybdenum, tungsten and niobium

摘要

Fire-resistant welding steel in the form of hollow profiles, supports or molded steel contains (in wt.%) 0.06-0.13 C, 0.15-0.50 Si, 1.0-2.0 Mn, maximum 0.025 P, maximum 0.02 S, 0.005-0.040 Al, 0.20-0.40 Mo, 0.40-0.70 W, 0.02-0.05 Nb and a balance of Fe with unavoidable impurities. A component made from the steel has a yield point at elevated temperature of at least 200 MPa at 600 deg. C and a CEIIW value of less than 0.5. - An INDEPENDENT CLAIM is also included for a process for the production of hot-rolled hollow profiles having a thickness of up to 30 mm made from the above steel comprising casting the steel into strands, hot rolling into rods and then into hollow profiles at at least 1200 deg. C before cooling in air.