ULTRA THICK STEEL PLATE AND MANUFACTURING METHOD FOR OFFSHORE STRUCTURE HAVING ULTRA-HIGH STRENGTH AND HIGH TOUGHNESS

摘要

The present invention relates to an ultra-thick steel plate having an ultra-high strength and high toughness for a marine structure and a method to manufacture the same and, more specifically, relates to the ultra-thick steel plate having the ultra-high strength and high toughness, and a steel plate manufactured in a method which can be applied to a marine structure or a ship, etc. to purify, store, and produce crude oil, gas, etc. A steel plate provided in the present invention has a high strength of a tensile strength of at least 690 MPa, and a yield strength of at least 770 MPa, and represents at least 69 J of high toughness at a low temperature of -60C; thereby maintaining stability for a long time in a harsh environment such as waves or a storm even when applied to a steel plate manufactured in the method and applied to produce crude oil or gas, etc.