HIGH STRENGTH STEEL WIRE ROD AND HIGH STRENGTH STEEL WITH EXCELLENT DELAY FRACTURE RESISTANCE AND MANUFACTURING METHOD THEREOF

摘要

Disclosed is a steel material capable of securing excellent anti-delay property and high strength through alloy composition and microstructure control, and a method for manufacturing the same. High-strength steel excellent in delayed fracture resistance according to an embodiment of the present invention, by weight, C: 0.4 to 0.6%, Si: 0.3% or less, Mn: 1.5 to 2.5%, Cr: 1.0% or less, Mo: 1.0 % Or less, V: 0.01 to 0.1%, P: 0.015% or less, S: 0.010% or less, Al: 0.01 to 0.1%, N: 0.003 to 0.02%, including the remaining Fe and unavoidable impurities, and the microstructure is a volume fraction Furnace contains 90% or more of lower bainite and 10% or less of retained austenite.