MARTENSITIC STEEL AND METHOD FOR PRODUCING SAME

摘要

Provided is martensitic steel which is used in structures such as buildings and bridges, and automotive underbody, and mechanical parts such as gears and is more suitably used for steel products such as thick steel sheets, shape steel, a deformed steel bar, steel bars, or steel wires. The martensitic steel has a microstructure of a martensite structure containing a chemical composition, by mass %, of Si: 1.0 to 3.5%, Mn: 4.5 to 5.5%, Al: 0.001 to 0.080%, Nb: 0.045% or less, and C having an amount in which the following regression equation (1) is satisfied and the maximum stress (TS) becomes 1800 to 2160 MPa, a balance being Fe and inevitable impurities of: P: 0.030% or less, S: 0.020% or less, and N: 0.010% or less, the martensitic steel having total elongation of 13 to 15%.;TS(maximum stress) [MPa]=4000×C[mass %]+1050  (1)

主权项

1. Martensitic steel having a microstructure of a martensite structure, containing a chemical composition, by mass %, of:
Si: 1.0 to 3.5%, Mn: 4.5 to 5.5%, Al: 0.001 to 0.080%, Nb: 0.045% or less, and C having an amount in which the following regression equation (1) is satisfied and the maximum stress (TS) becomes 1800 to 2160 MPa, a balance being Fe and inevitable impurities of: P: 0.030% or less, S: 0.020% or less, and N: 0.010% or less, wherein the martensitic steel has total elongation of 13 to 15%.
TS(maximum stress) [MPa]=4000×C[mass %]+1050  (1)