HOT-ROLLED STEEL WITH TENSILE STRENGTH OF 500 MPA OR MORE FOR WHEELS AND MANUFACTURING METHOD THEREFOR

摘要

Disclosed is a hot-rolled steel with a tensile strength of 500 MPa or more for wheels, with the chemical elements of the hot-rolled steel in mass percentages being: C: 0.09-0.2%, Mn: 0.8-1.2%, Al: 0.025-0.060%, and Nb: 0.01-0.10%, with the balance being Fe and other inevitable impurities. Disclosed is a method for manufacturing the hot-rolled steel for wheels. The manufacturing method has no heat treatment step and comprises the following steps: (1) smelting and casting; (2) heating a plate blank; (3) hot rolling; and (4) cooling in segments, wherein in the first stage, a steel plate is cooled to 650-750°C at a rate of 60-150°C/s, in the second stage, the steel plate is cooled in air for 5-20 s, in the third stage, the steel plate is cooled to 350-500°C at a rate of 60-150°C/s, and in the fourth stage, the steel plate is air-cooled to room temperature.