A process for manufacturing corrosion resistant metal components is disclosed. The process comprises abrasive blasting of a silicon-containing steel substrate followed by hot dip galvanizing, a second abrasive blasting process, treating with a mineral acid, and coating with a polymeric coating. The resulting corrosion resistance is enhanced.

Described herein is a method for treatment of a metallic surface, including the step of (A) contacting the metallic surface with a first aqueous composition, and a subsequent step of (B) contacting the metallic surface subsequent to step (A) with a second aqueous composition. Also described herein is a kit-of-parts including the first and second aqueous composition and a kit-of-parts including master-batches of the first and second aqueous compostions. Also described is a method of using the kit-of-parts for treating a metallic surface and substrates including the thus treated metallic surfaces.

Provided are a high-strength cold-rolled steel sheet and a hot-dip galvanized steel sheet comprising in % by weight: 0.05 to 0.3% of carbon (C); 0.6 to 2.5% of silicon (Si); 0.01 to 0.5% of aluminum (Al); 1.5 to 3.0% of manganese (Mn); and the remainder being Fe and unavoidable impurities, the steel sheet has a microstructure comprised of, in an area fraction, ferrite in an amount of 60% or less, lath-type bainite of 25% or more, martensite of 5% or more, and lath-type retained austenite in an amount of 5%, wherein the ferrite has an average grain diameter of 2 m or less and the ferrite satisfies Fn2, defined by relational expression 1, is 89% or more and Fa5, defined by relational expression 2, is 70% or less.

The present disclosure relates to: a plated steel sheet which is for hot forming, has excellent hydrogen embrittlement resistance, and includes an Al-based plating layer formed on the surface of a base steel sheet, wherein the average Ni content in the Al-based plating layer is 0.05 to 0.35 wt %; and a method for manufacturing same.

A method of manufacturing a low-density clad steel sheet, including: preparing a base material, a lightweight steel sheet including C: 0.3 to 1.0%, Mn: 4.0 to 16.0%, Al: 4.5 to 9.0%, and Fe; preparing cladding materials, each being martensitic carbon steel including C: 0.1 to 0.45%, Mn: 0.1 to 3.0%, and Fe; disposing the base material between the cladding materials to obtain a laminate; welding an edge of the laminate, and heating the welded laminate to 1050 to 1350? C.; finish-rolling the heated laminate to 750 to 1050? C. with a rolling reduction ratio of 30% or more in a first pass, to obtain a hot-rolled steel sheet; coiling the hot-rolled steel sheet at 400 to 700? C.; applying a cold-reduction ratio of 35 to 90% to obtain a cold-rolled steel sheet; and annealing the cold-rolled steel sheet at 550? C. or higher and A3+200? C. or lower of the cladding materials.

Provided is a galvannealed steel sheet having high strength and excellent deep drawability, and being further excellent in slab cracking resistance and secondary working embrittlement resistance. A base metal steel sheet of the galvannealed steel sheet has a chemical composition containing, in mass %: C: 0.0080% or less; Si: 0.7% or less; Mn: 1.0 to 2.5%; P: more than 0.030 to 0.048%; S: 0.025% or less; Al: 0.005 to 0.20%; N: 0.010% or less; Ti: 0.005 to 0.040%; Nb: 0.005 to 0.060%; and B: 0.0005 to 0.0030%, with the balance being Fe and impurities, satisfying Formula (1) to (4). A galvannealed layer contains 7 to 15 mass % of Fe.

25P+4Si3.6(1)

BX10.0005(2)

C(12/93)NbX20.0035(3)

110Si+48Mn+550P120(4)

A steel sheet coated with a metallic coating is provided. The steel sheet includes from 2.0 to 24.0% by weight of zinc, from 7.1 to 12.0% by weight of silicon, optionally from 1.1 to 8.0% by weight of magnesium, and optionally additional elements chosen from Pb, Ni, Zr, or Hf, the content by weight of each additional element being less than 0.3% by weight, the balance being aluminum and optionally unavoidable impurities and residual elements. The ratio Al/Zn is above 2.9.

Provided is a method of manufacturing a zinc-plated steel sheet. The method includes: coating a metal on the steel sheet on a steel sheet; annealing the metal coated steel sheet; and zinc plating the annealed steel sheet by dipping in a molten zinc plating bath. Further provided is a method of manufacturing a hot-press part including: coating a metal on the steel sheet on a steel sheet; annealing the metal coated steel sheet; zinc plating the annealed steel sheet by dipping in a molten zinc plating bath; heating the zinc-plated steel sheet; and press forming the heated steel sheet.

Provided is a method of manufacturing a hot-dip galvanized steel sheet. According to an aspect of the present invention, the method may include preparing a base steel sheet, forming a iron (Fe)-plated layer on the prepared base steel sheet, oxidation heating the steel sheet having the Fe-plated layer formed thereon at a temperature ranging from 600 C. to 800 C., maintaining the heated steel sheet at a temperature ranging from 750 C. to 900 C. for 5 seconds or more in a reducing atmosphere with a dew point of between -30 C. to 5 C. including 20 ppm or less of oxygen, 1 vol % to 20 vol % of H.sub.2, and N.sub.2 as well as unavoidable gases as a remainder, cooling the maintained steel sheet, and plating the cooled steel sheet by dipping in a hot-dip galvanizing bath.

Provided is a zinc-plated steel sheet for hot pressing having outstanding surface characteristics, comprising: a steel foundation plate comprising a metal surface diffusion layer of which the Gibbs free energy reduction per mole of oxygen during oxidation is less than that of Cr, an aluminum-rich layer containing at least 30 wt. % of aluminum formed on the surface diffusion layer, and a zinc plating layer formed on the aluminum-rich layer. In this way, a metal having a low affinity for oxygen is coated to an effective thickness prior to annealing and thus the creation of annealing oxides at the surface of the steel sheet is suppressed and a uniform zinc plating layer is formed, and alloying of the zinc plating layer is promoted during press-processing heat treatment. Cracking in the steel foundation plate during hot press molding is prevented.