Cold-rolled steel sheet for hot forming excellent in corrosion resistance and spot weldability, hot-formed member, and manufacturing method thereof

摘要

One aspect of the present invention is, by weight, C: 0.1-0.4%, Si: 0.5-2.0%, Mn: 0.01-4.0%, Al: 0.001- 0.4%, P: 0.001 to 0.05%, S: 0.0001 to 0.02%, Cr: 0.5% or more and less than 3.0%, N: 0.001 to 0.02% Corrosion resistance and spots, including the remaining Fe and other inevitable impurities, satisfying the following formula (1), and having a Si amorphous oxide layer having a thickness of 1 nm to 100 nm formed continuously or discontinuously on the surface The present invention relates to a cold-rolled steel sheet for hot forming excellent in weldability. Formula (1): 1.4 ≦ 0.4 * Cr + Si ≦ 3.2 (In the above formula (1), each element symbol is a value obtained by measuring the content of each element in weight%.)