A steel sheet for cans has a chemical composition containing, by mass %, C: 0.015% or more and 0.150% or less, Si: 0.04% or less, Mn: 1.0% or more and 2.0% or less, P: 0.025% or less, S: 0.015% or less, Al: 0.01% or more and 0.10% or less, N: 0.0005% or more and less than 0.0050%, Ti: 0.003% or more and 0.015% or less, B: 0.0010% or more and 0.0040% or less, and the balance being Fe and inevitable impurities. The steel sheet has a microstructure including a ferrite phase as a main phase and at least one of a martensite phase and a retained austenite phase as a second phase, the total area fraction of the second phase being 1.0% or more, and the sheet has a tensile strength of 480 MPa or more, a total elongation of 12% or more, and a yield elongation of 2.0% or less.

A steel sheet for cans has a chemical composition containing, by mass %, C: 0.015% or more and 0.150% or less, Si: 0.04% or less, Mn: 1.0% or more and 2.0% or less, P: 0.025% or less, S: 0.015% or less, Al: 0.01% or more and 0.10% or less, N: 0.0005% or more and less than 0.0050%, Ti: 0.003% or more and 0.015% or less, B: 0.0010% or more and 0.0040% or less, and the balance being Fe and inevitable impurities. The steel sheet has a microstructure including a ferrite phase as a main phase and at least one of a martensite phase and a retained austenite phase as a second phase, the total area fraction of the second phase being 1.0% or more, and the sheet has a tensile strength of 480 MPa or more, a total elongation of 12% or more, and a yield elongation of 2.0% or less.

The present invention provides steel sheet excellent in cold formability and ductility after heat treatment and a method for production thereof. The steel sheet of the present invention is steel sheet which has a chemical composition containing, by mass %, C: 0.10 to 0.40%, Si: 0.30 to 1.00%, Mn: 0.30 to 1.00%, Al: 0.001 to 0.10%, P: 0.0001 to 0.02%, and S: 0.0001 to 0.01% and having a balance of Fe and impurities, which steel sheet characterized in that a ratio (B/A) of the number of carbides at the ferrite grain boundaries (B) to the number of carbides inside the ferrite grains (A) is over 1, a ferrite grain size is 5 m to 50 m, an average grain size of carbides is 0.4 m to 2.0 m, a pearlite area ratio is 6% or less, and a Vicker's hardness is 120 HV to 170 HV.

By first fluxing a steel long product with novel specific flux compositions, it is possible to continuously produce, more uniform, smoother and void-free galvanized coatings on such steel long products in a single hot dip galvanization step making use of zinc-aluminum alloys or zinc-aluminum-magnesium alloys with less than 95 wt. % zinc. This is achieved by providing potassium and sodium chlorides in a KCl/NaCl weight ratio of at least 2.0 in a flux composition comprising (a) more than 40 and less than 70 weight % zinc chloride, (b) from 10 to 30 weight % ammonium chloride, (c) more than 6 and less than 30 weight % of a set of at least two alkali metal chlorides.

By first fluxing a steel long product with novel specific flux compositions, it is possible to continuously produce, more uniform, smoother and void-free galvanized coatings on such steel long products in a single hot dip galvanization step making use of zinc-aluminum alloys or zinc-aluminum-magnesium alloys with less than 95 wt. % zinc. This is achieved by providing potassium and sodium chlorides in a KCl/NaCl weight ratio of at least 2.0 in a flux composition comprising (a) more than 40 and less than 70 weight % zinc chloride, (b) from 10 to 30 weight % ammonium chloride, (c) more than 6 and less than 30 weight % of a set of at least two alkali metal chlorides.

In a method for cleaning a non-machined aluminum alloy product involving alkaline degreasing and treatment thereof after alkaline pickling with an acidic solution, the aluminum alloy product undergoes (a) initial acid cleaning before alkaline degreasing or (b) alkaline degreasing, followed by a subsequent acid rinse, alkaline treatment anew and an additional acid rinse thereafter. The aluminum alloy product may be a rolled aluminum alloy strip, a rolled aluminum alloy sheet and an aluminum alloy profile.

Provided is a steel sheet that may be used for automobile parts and the like, and to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansion ratio, and an excellent yield ratio evaluation index, and a method for manufacturing the same. The steel sheet includes: by wt %, C: 0.1 to 0.25%, Si: 0.01 to 1.5%, Mn: 1.0 to 4.0%, Al: 0.01 to 1.5%, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, B: 0.0005 to 0.005%, a balance of Fe, and unavoidable impurities; and as microstructures, bainite, tempered martensite, fresh martensite, retained austenite and unavoidable structures.

Provided is a steel sheet that may be used for automobile parts and the like, and to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansion ratio, and an excellent yield ratio evaluation index, and a method for manufacturing the same. The steel sheet includes: by wt %, C: 0.1 to 0.25%, Si: 0.01 to 1.5%, Mn: 1.0 to 4.0%, Al: 0.01 to 1.5%, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, B: 0.0005 to 0.005%, a balance of Fe, and unavoidable impurities; and as microstructures, bainite, tempered martensite, fresh martensite, retained austenite and unavoidable structures.

An embodiment of the present invention provides a high strength hot-dip galvanized steel sheet having excellent plating adhesion and weldability and a method of manufacturing same, wherein: the steel sheet comprises a base steel sheet and a hot-dip galvanized layer formed on one surface or both surfaces of the base steel sheet, the base steel sheet comprising, in weight %, carbon (C): 0.1-0.3%, silicon (Si): 0.1-2.0%, aluminum (Al): 0.1-1.5%, manganese (Mn): 1.5-3.0%, and the balance being Fe and inevitable impurities, the sum of Si and Al satisfying 1.2-3.5%, the ratio (Al/Si) of Al and Si satisfying 0.5-2.0; the steel sheet comprises an internal oxidation layer with a thickness of 1-5 m directly below the surface of the base steel sheet; and the decarburization rate in a region from directly below the surface of the base steel sheet to 50 m is 50% or more.

An embodiment of the present invention provides a high strength hot-dip galvanized steel sheet having excellent plating adhesion and weldability and a method of manufacturing same, wherein: the steel sheet comprises a base steel sheet and a hot-dip galvanized layer formed on one surface or both surfaces of the base steel sheet, the base steel sheet comprising, in weight %, carbon (C): 0.1-0.3%, silicon (Si): 0.1-2.0%, aluminum (Al): 0.1-1.5%, manganese (Mn): 1.5-3.0%, and the balance being Fe and inevitable impurities, the sum of Si and Al satisfying 1.2-3.5%, the ratio (Al/Si) of Al and Si satisfying 0.5-2.0; the steel sheet comprises an internal oxidation layer with a thickness of 1-5 m directly below the surface of the base steel sheet; and the decarburization rate in a region from directly below the surface of the base steel sheet to 50 m is 50% or more.