Posco Co., Ltd

Posco

Tae-Oh Lee

Jae-Hoon Lee

Min-Seo Koo

Young-Roc Im

Jong-Chan Park

Tae-Kyo Han

Min-Hong Seo

Jong-Kweon Kim

Kang-Hwan Ahn

Il-Hyun Kim

Provided is a high-strength steel sheet including: 0.12% to less than 0.17% of carbon (C), 0.3% to 0.8% of silicon (Si), 2.5% to 3.0% of manganese (Mn), 0.4% to 1.1% of chromium (Cr), 0.01% to 0.3% of aluminum (Al), 0.01% to 0.03% of niobium (Nb), 0.01% to 0.03% of titanium (Ti), 0.001% to 0.003% of boron (B), 0.04% or less of phosphorus (P), 0.01% or less of sulfur(S): 0.01% or less of nitrogen (N), and a balance of iron (Fe) and inevitable impurities. The contents of C, Si, and Al satisfy: [C]+([Si]+[Al])/5≤0.35 wt %. A microstructure includes more than 1% to 4% or less of retained austenite, more than 10% to 20% or less of fresh martensite, 5% or less (excluding 0%) of ferrite, more than 50% to 70% or less of tempered martensite, and a balance of bainite.

High-strength steel sheet and manufacturing method thereof

Provided is a steel sheet and a method for manufacturing same, the steel sheet, which can be used for automobile parts and the like, having superb bendability, and excellent balance of strength and ductility and of strength and hole expansion ratio. The steel sheet includes: by wt %, C: 0.25 to 0.75%, Si: 4.0% or less, Mn: 0.9 to 5.0%, Al: 5.0% or less, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, a balance of Fe, and unavoidable impurities; and as microstructures, ferrite which is a soft structure, and tempered martensite, bainite, and retained austenite which are hard structures.

High strength steel sheet having excellent workability and method for manufacturing same

Provided is a vehicle seat structure that is lighter than a steel vehicle seat structure while providing the same function thereof. For this, the vehicle seat structure includes a seat cushion frame and a seat back frame connected to the seat cushion frame. At least one of components constituting the seat back frame and the seat cushion frame is formed of a magnesium plate produced through a rolling process and that has a texture.

Vehicle seat structure

Growing community of inventors

Gwangyang-si, South Korea

Tae-Oh Lee