This invention relates to a sheet or pre-coated blank comprising a steel substrate for heat treatment, overlaid on at least a part of at least one of its principal faces, by a pre-coating having, at least one layer of aluminum or aluminum alloy overlaid, on at least a part of the above-mentioned pre-coating, by a polymerized layer having a thickness between 2 and 30 m composed of a polymer that does not contain silicon, and the nitrogen content of which, is greater than 1% by weight expressed in relation to the above-mentioned layer, wherein the above-mentioned polymerized layer contains carbon pigments in a quantity between 3 and 30% by weight, expressed in relation to said layer.

A thermal-assisted method deforms a sheet metal assembly having constrained ends. A focus bending area located between the constrained ends is heated. The focus bending area is bent while the sheet metal assembly is within an elevated bending temperature range. A sheet metal assembly may be formed by this method, which includes an outer metal sheet and an inner metal sheet fixed together to form constrained ends. The sheet metal assembly has a bend formed therein between the first and second constrained ends, wherein each metal sheet is bent at the bend with a maximum gap between the inner and outer metal sheets at the bend. The maximum gap is no greater than five times the thickness of one of the inner and outer metal sheets, and the bend has a radius less than three times the thickness of one of the inner and outer sheets.

A sheet or blank is provided which includes a substrate and pre-coating on at least one face of the substrate. A polymerized layer overlies at least a part of the pre-coating and has a thickness from 2 m to 30 m, a nitrogen content of less than 1% by weight, carbon pigments in a quantity from 3 to 30% by weight and does not include a polymer with silicon. A welded blank, part and fabrication methods are also provided.

A method for producing a flywheel includes producing a damping plate part by permanently connecting at least a first metallic plate element provided for the flywheel to at least one further material layer to form a sandwich component. According to the method, the first plate element is connected by a joining process to at least a second, parallel plate layer, so that they lie on one another to form a disc-shaped structural unit. According to the method, at least two sheet metal layers from different materials and/or at least two sheet metal layers having different material strengths are connected with each other. This enables a large variance for the production of flywheels. In this way, it is possible, for example, to produce a flywheel having a plurality of superimposed plates adapted to the respective load situation in a defined flexibility.

A fabrication method for a press hardened part is provided. A sheet or a steel substrate blank for heat treatment is provided. A pre-coating is applied. The pre-coating has at least one layer of aluminum or aluminum alloy in contact with the steel substrate on at least one of the principal faces of the sheet or blank. Then a polymerized layer is deposited on the pre-coating. The polymerized layer has a thickness between 2 and 30 m. The polymerized layer does not contain silicon, has a nitrogen content of less than 1% by weight and carbon pigments in a quantity between 3 and 30% by weight. The blank or the sheet is heated to obtain an interdiffusion between the steel substrate and the pre-coating and to give the steel a partly or totally austenitic structure. Then the blank or the sheet is hot stamped to obtain a part. The part is cooled by holding the part in a stamping tool so that the microstructure of the steel substrate includes, at least in a portion of the part, martensite or bainite.

A hot stamping method for simultaneously forming workpieces includes steps of: performing laser welding to which an aluminum filler wire is applied to a welding site between the two or more sheets of blanks, and hot-stamping the two or more sheets of blanks, which are welded in the step of performing the laser welding.

A part obtained by austenitization followed by hot stamping and hardening by holding in the stamping tool a sheet or blank is provided, including, a steel substrate, a precoating having at least one layer of aluminum or aluminum alloy, a microstructure of a steel substrate including martensite and/or bainite, a coating on at least one face of the steel substrate resulting from the interdiffusion between the steel substrate and the pre-coating and an oxide layer overlying the coating, an average content by weight of oxygen between 0 and 0.01 m below a surface of the part being less than 25%, and the average percent by weight of oxygen between 0.1 and 0.2 m below the surface being less than 10%.

Provided is a method for manufacturing an iron core that enables reduction of variations in dimension of a plurality of metal plates that occur during pressing of the laminate of these metal plates. The method includes: a laminate preparation step of stacking a plurality of metal plates to prepare a laminate; a pressing step of giving a temperature gradient to the laminate and pressing the laminate with a pressing machine having a punch and a die; and a temperature-gradient removal step of removing the temperature gradient from the laminate. The pressing step gives the temperature gradient to the laminate so that the temperature rises from the punch-side to the die-side in the stacking direction of the laminate.

A die set for bending a metal plate workpiece includes a lower die for placing the workpiece, an upper die having a pressing surface which presses the workpiece toward the lower die by movement, a lower movable part provided in the lower die and being slidable in the same direction as the direction of the upper die movement, and a gas spring elastically supporting the lower movable part from below. The pressing surface of the upper die is moved, contacts with the upper surface of the workpiece and presses the workpiece toward the lower die. The lower movable part being elastically supported by the gas spring from below brings an opposing surface into contact with the lower surface of the workpiece and makes the upper die to be close to the lower die while applying force in the upward which is opposite direction of the upper die movement.

A blanking punch which extends from a first portion to a second portion along a blanking direction is provided. The second portion has a cutting edge. An engaging portion is provided/designed between the first portion and the second portion. The engaging portion enables the blanking punch to be removed from a workpiece counter to the blanking direction.