According to an embodiment, a method for manufacturing a thin plate comprises placing a copper piece on a side of an aluminum piece, forming a heterogeneous metal joined body by performing friction welding on the side of the aluminum piece and a side of the copper piece to thereby form a spread layer of the aluminum piece on the side of the aluminum piece, and a spread layer of the copper piece on the side of the copper piece, the respective spread layers of the aluminum piece and the copper piece being mixed into a mixed layer that is then cured, and forming the thin plate by roll-milling the heterogeneous metal joined body.

This invention provides a relatively thick roll-bonded laminate that exhibits a high Erichsen value and excellent molding workability. Such roll-bonded laminate is composed of a stainless steel layer and a non-stainless steel metal layer, and it is characterized in that thickness T is 0.2 mm to 3 mm and a correlation between a proportion P.sub.SUS of thickness T.sub.SUS of the stainless steel layer relative to thickness T and a half width FWHM.sub.200 of a peak exhibiting a crystal plane orientation (200) determined by X-ray diffraction analysis of the stainless steel layer side satisfies the correlation represented by the formula: FWHM.sub.200≤0.0057P.sub.SUS+0.4.

This invention provides a relatively thick roll-bonded laminate that exhibits a high Erichsen value and excellent molding workability. Such roll-bonded laminate is composed of a stainless steel layer and a non-stainless steel metal layer, and it is characterized in that thickness T is 0.2 mm to 3 mm and a correlation between a proportion P.sub.SUS of thickness T.sub.SUS of the stainless steel layer relative to thickness T and a half width FWHM.sub.200 of a peak exhibiting a crystal plane orientation (200) determined by X-ray diffraction analysis of the stainless steel layer side satisfies the correlation represented by the formula: FWHM.sub.200≤0.0057P.sub.SUS+0.4.

Provided is a density clad steel sheet having excellent strength and plateability, the clad steel sheet including a base metal, and a clad material provided at both sides of the base metal, wherein the base metal is a ferrite-austenitic duplex lightweight steel sheet comprising, by wt %, 0.3-0.7% of C, 2.0-9.0% of Mn, 4.5-8.0% of Al and the balance of Fe and inevitable impurities, and the clad material is a ferrite carbon steel comprising, by wt %, 0.0005-0.2% of C, 0.05-2.5% of Mn and the balance of Fe and inevitable impurities.

Provided is a low-density clad steel sheet having excellent formability and fatigue properties, including a base material; and cladding materials provided on both side surfaces of the base material, wherein the base material is a lightweight steel sheet including, by weight, C: 0.3 to 1.0%, Mn: 4.0 to 16.0%, Al: 4.5 to 9.0%, and a remainder of Fe and inevitable impurities, and each of the cladding materials is martensitic carbon steel including, by weight, C: 0.1 to 0.45%, Mn: 1.0 to 3.0%, and a remainder of Fe and inevitable impurities.

Provided is a low-density clad steel sheet having excellent formability and fatigue properties, including a base material; and cladding materials provided on both side surfaces of the base material, wherein the base material is a lightweight steel sheet including, by weight, C: 0.3 to 1.0%, Mn: 4.0 to 16.0%, Al: 4.5 to 9.0%, and a remainder of Fe and inevitable impurities, and each of the cladding materials is martensitic carbon steel including, by weight, C: 0.1 to 0.45%, Mn: 1.0 to 3.0%, and a remainder of Fe and inevitable impurities.

A press-hardened steel assembly after hot stamping/hot forming including a core layer having a tensile strength of ≥about 1,800 megapascals to ≤about 2,200 megapascals and ≥about 90 volume % martensite, the core layer having a first thickness ≥about 40% to ≤about 96% of the thickness of the press-hardened steel assembly; and a first surface layer along a first surface of the core, the first surface layer having a tensile strength of ≥about 800 megapascals to ≤about 1,200 megapascals and ≥about 90 volume % martensite and bainite. The press-hardened steel assembly has a tensile strength of ≥about 1,600 megapascals to ≤about 2,000 megapascals and a VDA 238-100 bending angle of ≥about 50° to ≤about 80°.

A press-hardened steel assembly after hot stamping/hot forming including a core layer having a tensile strength of ≥about 1,800 megapascals to ≤about 2,200 megapascals and ≥about 90 volume % martensite, the core layer having a first thickness ≥about 40% to ≤about 96% of the thickness of the press-hardened steel assembly; and a first surface layer along a first surface of the core, the first surface layer having a tensile strength of ≥about 800 megapascals to ≤about 1,200 megapascals and ≥about 90 volume % martensite and bainite. The press-hardened steel assembly has a tensile strength of ≥about 1,600 megapascals to ≤about 2,000 megapascals and a VDA 238-100 bending angle of ≥about 50° to ≤about 80°.

A foil stock comprising at least one AlFeSi-based layer. The foil stock according to the invention comprises an AlMg-based core layer and an AlFeSi-based cladding layer of not more than 0.05% by weight, in particular of not more than 0.03% by weight magnesium (Mg), thereby ensuring high strength and good deformation and coating properties of a carrier foil produced from said foil stock.

A foil stock comprising at least one AlFeSi-based layer. The foil stock according to the invention comprises an AlMg-based core layer and an AlFeSi-based cladding layer of not more than 0.05% by weight, in particular of not more than 0.03% by weight magnesium (Mg), thereby ensuring high strength and good deformation and coating properties of a carrier foil produced from said foil stock.