HOT-ROLLED STEEL SHEET, METHOD OF MANUFACTURING THE HOT-ROLLED STEEL SHEET AND METHOD OF MANUFACTURING OIL TUBULAR COUNTRY GOODS USING THE HOT-ROLLED STEEL SHEET

摘要

PURPOSE: A hot-rolled steel plate, manufacturing method thereof, and a method for manufacturing a steel pipe using the same are provided to upgrade to a steel grade of a tensile strength of more than 950 MPa, an yield strength of 800 to 8000 MPa, and an elongation rate of 14% through QT(Quenching and Tempering) after pipe production. CONSTITUTION: The equation(1) is 6≤[Mn]/[Si]≤9.