Highly formable and easily phosphated high-manganese cold-rolled steel plate having tensile strength of 1000-1600 mpa, and manufacturing method therefor

Abstract

Provided are a high-manganese cold-rolled steel plate having a tensile strength of 1000-1600 MPa and its manufacturing method. The steel plate is a composite structure comprising a matrix and a surface layer, wherein the matrix is a face-centered cubic phase structure comprising high-density twin crystals and low-density dislocations, wherein the twin crystal density is (1~10)×105 m−1, and the dislocation density is (1~10)×1013 m−1; wherein the matrix comprises the following chemical composition by weight percentage: C: 0.5~0.8%, Mn: 14~18%, Si: 0.1~0.5%, RE: 0.01~0.10%, P: ≤0.020%, S: ≤0.010%, Al: 1.2~1.8%, N: 0.01~0.1%, with a balance of Fe and unavoidable impurities, and also satisfies: Mn+25C−1.5Al≥28%, Si+20RE≥1.0%, wherein the surface layer is a ferroalloy layer having a body-centered cubic phase structure, which comprises C≤0.03 wt %, Mn≤0.5 wt %, Al≤0.1 wt %, wherein the high-manganese cold-rolled steel plate has a yield strength of 700~1400 MPa, a tensile strength of 1000~1600 MPa, an elongation of 20~55%, and satisfies TS2×EL≥49TPa2%.

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