High-strength steel sheet and method for producing same

Abstract

The present invention is directed to providing a steel sheet having excellent LME resistance, high strength, and good formability by a method different from conventional techniques, and to providing a method for manufacturing the steel sheet. A high-strength steel sheet containing particular components and having a particular microstructure, wherein the relationship between the amount of dissolved Nb (Nbsol), the amount of Nb in Nb precipitates having a particle size of less than 20 nm (Nbpre), and the total amount of Nb contained in the steel sheet (Nb) satisfies the following Formula 1, and wherein the amount of diffusible hydrogen in the steel is 0.50 mass ppm or less: Nbsol / Nb+Nbpre / Nb≥0.40 where Nbsol represents the amount (mass %) of dissolved Nb, and Nbpre represents the amount (mass %) of Nb in Nb precipitates having a particle size of less than 20 nm.

Images