Provided is a steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if the crystal orientations of an Fe-based electroplating layer and a Si-containing cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet. Provided is an Fe-based electroplated steel sheet having a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; and an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of more than 20.0 g/m.sup.2, where the crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50% at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.

A transition structure includes a metallic portion, a fiber portion including a plurality of tows embedded within the metallic portion and extending out from the metallic portion forming a fabric, and a binding material forming a matrix surrounding the fiber portion embedded within the metallic portion. The fiber portion may be attached to or form part of a composite vehicle component. The transition structure may join a metallic component and a composite component. The transition structure may be manufactured by creating first channels within a layer of a metallic substrate, inserting fiber tows into the first channels, placing a first metallic layer over the metallic substrate and the fiber tows, consolidating the metallic layer to the metallic substrate, and binding the fiber tows within a resin. Prior to binding, additional layers of channels and fiber tows may be consolidated onto the first metallic layer.

A transition structure includes a metallic portion, a fiber portion including a plurality of tows embedded within the metallic portion and extending out from the metallic portion forming a fabric, and a binding material forming a matrix surrounding the fiber portion embedded within the metallic portion. The fiber portion may be attached to or form part of a composite vehicle component. The transition structure may join a metallic component and a composite component. The transition structure may be manufactured by creating first channels within a layer of a metallic substrate, inserting fiber tows into the first channels, placing a first metallic layer over the metallic substrate and the fiber tows, consolidating the metallic layer to the metallic substrate, and binding the fiber tows within a resin. Prior to binding, additional layers of channels and fiber tows may be consolidated onto the first metallic layer.

Method for joining of at least two unweldable materials, non-weldable directly to each other with thermal joining processes in a lap joint configuration, where a two step sequence is used consisting of a first step to apply a thermomechanical or mechanical surface protection layer on the surface of an unweldable material and a second step, where a thermal joining process is used to joint the sprayed layer with an applied layer sheet.

A cold-rolled and heat-treated steel sheet, has a composition comprising, by weight percent: n0.10%C0.25%, 3.5%Mn6.0%, 0.5%Si2.0%, 0.3%Al1.2%, with Si+Al0.8%, 0.10%Mo0.50%, S0.010%, P0.020%, N0.008%. The cold-rolled steel sheet has a microstructure consisting of, in surface fraction: between 10% and 45% of ferrite, having an average grain size of at most 1.3 m, the product of the surface fraction of ferrite by the average grain size of the ferrite being of at most 35 m %, between 8% and 30% of retained austenite, the retained austenite having an Mn content higher than 1.1*Mn %, Mn % designating the Mn content of the steel, at most 8% of fresh martensite, at most 2.5% of cementite and partitioned martensite.

A cold-rolled and heat-treated steel sheet, has a composition comprising, by weight percent: n0.10%C0.25%, 3.5%Mn6.0%, 0.5%Si2.0%, 0.3%Al1.2%, with Si+Al0.8%, 0.10%Mo0.50%, S0.010%, P0.020%, N0.008%. The cold-rolled steel sheet has a microstructure consisting of, in surface fraction: between 10% and 45% of ferrite, having an average grain size of at most 1.3 m, the product of the surface fraction of ferrite by the average grain size of the ferrite being of at most 35 m %, between 8% and 30% of retained austenite, the retained austenite having an Mn content higher than 1.1*Mn %, Mn % designating the Mn content of the steel, at most 8% of fresh martensite, at most 2.5% of cementite and partitioned martensite.

A method for producing a welded metal blank (16) includes cutting a first initial metal sheet (1) and a second initial metal sheet (3) from a first and second metal strip (4); joining the first and second initial metal sheets (1,3) by welding so as to obtain an initial welded metal blank (9), the initial welded metal blank (9) comprising a weld joint (10) joining the first and the second initial metal sheets (1,3); and cutting said initial welded metal blank (9) by a process involving metal melting so as to obtain at least one final welded metal blank (16) comprising a first metal blank portion (17) and a second metal blank portion (18) joined by a weld joint portion (19) consisting of a portion of the weld joint (10) obtained during the joining step.

A method of preparing a pipe-section for welding to another pipe-section to form a pipeline comprising a plurality of said pipe-sections, the method comprising at least the steps of: (i) providing a pipe-section having first and second pipe-ends; (ii) defining a first portion L1 of the longitudinal length of the pipe-section from the first pipe-end being in the range 3% to 40% of the overall length of the pipe-section; (iii) defining a second portion L2 of the longitudinal length of the pipe-section from the end of the first portion L1 towards the second pipe-end; (iv) heating at least the first portion L1 to at least a first temperature T1 of at least 500 C. for at least 2 minutes; (v) maintaining a second temperature T2 of the second portion L2 during step (iv) below the first temperature T1. The invention is able to reduce the strain capacity during reel-laying of a pipeline formed from a plurality of pipe sections formed by the invention.

Provided is a resistance spot welding method that inhibits, in accordance with the degree of axis misalignment between electrodes, the occurrence of cracking in a weld regardless of the steel grade. In resistance spot welding methods according to the present invention, H (ms) is an electrode force retaining time after completion of current passage, D (mm) is an amount of axis misalignment between the electrodes, t (mm) is a total sum of sheet thicknesses of a plurality of overlapping steel sheets, T (MPa) is a tensile strength of a steel sheet having a highest tensile strength among the plurality of steel sheets, F (N) is an electrode force, and d (mm) is a tip diameter of one electrode of the pair of electrodes that has a smaller tip diameter. The electrode force retaining time H is specified to be a predetermined value or greater.

Provided is a resistance spot welding method that inhibits, in accordance with the degree of axis misalignment between electrodes, the occurrence of cracking in a weld regardless of the steel grade. In resistance spot welding methods according to the present invention, H (ms) is an electrode force retaining time after completion of current passage, D (mm) is an amount of axis misalignment between the electrodes, t (mm) is a total sum of sheet thicknesses of a plurality of overlapping steel sheets, T (MPa) is a tensile strength of a steel sheet having a highest tensile strength among the plurality of steel sheets, F (N) is an electrode force, and d (mm) is a tip diameter of one electrode of the pair of electrodes that has a smaller tip diameter. The electrode force retaining time H is specified to be a predetermined value or greater.