NON-QUENCHED AND TEMPERED STEEL HAVING ULTRAFINE GRAINED PEARLITE STRUCTURE AND METHOD OF MANUFACTURING THE SAME

摘要

This invention relates to a method of manufacturing non-quenched and tempered steel having an ultrafine grained pearlite structure, including hot forging a steel material so as to be high-temperature compression deformed, thus obtaining a hot forged body; rapidly cooling the hot forged body to a low-temperature pearlite transformation range, thus obtaining a supercooled hot forged body; isothermally holding the supercooled hot forged body in the low-temperature pearlite transformation range so as to be isothermally transformed; and air-cooling the hot forged body; and to non-quenched and tempered steel manufactured thereby.