HIGH STRENGTH STEEL SHEET FOR HOT FORMING WITH EXCELLENT HEAT TREATMENT PROPERTY, HOT FORMED HARDENING MEMBER AND MANUFACTURING METHODS THEREOF

摘要

The present invention in weight%, C: 0.2 ~ 0.5%, Si: 0.01 ~ 1.5%, Mn: 0.5 ~ 2.0%, P: 0.1% or less (excluding 0%), S: 0.03% or less (excluding 0% ), soluble Al: 0.1% or less (0% is excluded), N: 0.01 ~ 0.1%, Cr: 0.1 to 2.0%, the rest is characterized in that the composition of Fe and other impurities are not more than the hot molded around the tensile strength is 800MPa that the heat treatment has excellent ultra-high strength steel sheet hot forming processing and to a method of manufacturing the same. In addition, after the hot forming and quenching the steel sheet, to a curable heat treatment member and a manufacturing method characterized in that it has a tensile strength of at least 1800MPa. ; The present invention after the former hot forming a steel sheet having a tensile strength and provides less than 800MPa, a tensile strength hot-forming and rapid cooling can be effective with more than 1800MPa. Further, after the coating has the effect to increase the yield strength of at least 100MPa with. ; Yield strength (yield strength), high strength (high strength steel), hot forming (hot press forming), the structural member (reinforcement), hardenability (hardenability)