Provided is a plated steel material which can be used for an automobile, a household appliance, a building material, and the like and, more particularly, to a zinc alloy plated steel material having excellent corrosion resistance after being processed and a method for manufacturing the same.

The present invention related to a structural steel sheet having excellent seawater resistance and having excellent corrosion resistance in environments in which corrosion is accelerated by seawater, and a method for manufacturing same.

Disclosed are high-strength ferritic stainless steel STS430, which has a yield strength of 350 MPa or greater and can be applied to a clamp of a vehicle or a common hose, and a manufacturing method thereof. The high-strength ferritic stainless steel for a clamp, according to one embodiment of the present invention, comprises, by weight, 0.04-0.1% of C, 0.2-0.6% of Si, 0.01-1.5% of Mn, 14.0-18.0% of Cr, 0.005-0.2% of Al, 0.005-0.2% of V, 0.02-0.1% of N, and the remainder as Fe and inevitable impurities, satisfies Expressions (1) and (2), and has at least 2.5×10.sup.6 precipitates having a mean diameter of 0.5 μm or less per mm.sup.2. (1) 0.35%≤Si+Al+V≤0.6% (2) 0.09%≤C+N≤0.12%

The present disclosure relates to a thick steel material that can be appropriately used as a line pipe, a sour-resistant material and, more particularly, to a high-strength steel material having excellent sulfide stress corrosion cracking resistance and excellent resistance against propagation of sulfide stress corrosion cracking, and a method of manufacturing the steel material.

Provided is a steel sheet which can be used for automobile parts and the like, and relates to a steel sheet having an excellent balance of strength and ductility and an excellent balance of strength and hole expansibility, and excellent bending workability, and a method for manufacturing same.

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.

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 excellent bending workability, and excellent balance of strength and ductility and of strength and hole expansibility.

A steel material for a vacuum tube according to an aspect of the present disclosure may include C: 0.1˜0.2%, Si: 0.05∞0.5%, Mn: 1.0∞1.6%, Ni: 0.5∞1.0%, Cr: 1.5∞4.0%, and the balance of Fe and unavoidable impurities in percentage by weight, and may have a complex structure of ferrite and pearlite as a microstructure.

The present disclosure relates to a high-strength hot-dip galvanized steel sheet having excellent surface quality and electrical resistance spot weldability, and a method for manufacturing the same. A galvanized steel sheet according to an aspect of the present disclosure is a galvanized steel sheet including a base steel sheet and a zinc-based plating layer formed on a surface of the base steel sheet, wherein a ratio (a/b) of a hardness of a surface layer portion (a) to a hardness of an internal portion (b) of the base steel sheet may be less than 0.95.

Provided is a hot rolled steel sheet having a predetermined chemical composition and a microstructure comprising, by area ratio, pearlite: 90 to 100% and pro-eutectoid ferrite: 0 to 10%, wherein the pearlite has an average lamellar spacing of 0.08 to 0.30 μm, and the percentage of cementite in the pearlite having a major axis length of more than 0.3 μm and an aspect ratio of less than 3.0 is less than 15%.