Abstract: A process for the industrial production of wear-resistant steel pipes having an optimized life. The process includes providing a wear-resistant, hardenable steel sheet in an unhardened or tempered state, shaping the steel sheet into a tubular preform in which two longitudinal edges of the steel sheet are positioned opposite one another with a welding gap extending between the two edges, welding the longitudinal edges by forming a welded seam which closes the welding gap, thereby forming a steel pipe, and heat treating the steel pipe. The heat treatment of the steel pipe includes heating the steel pipe at an average heating rate of 5-400 K/s to a hold temperature which is ? the Ac3 temperature of the steel and ?1100° C., holding the steel pipe at the hold temperature for 1-120 s, and cooling the steel pipe at an average cooling rate of 10-600 K/s to room temperature.

Abstract: “A method for thermally treating a flat steel product, a thermally treated flat steel product and use thereof. The method includes providing a flat steel product with a structure with a first hardness. The flat product is heated at least in sections to an austenitizing temperature. The heated flat product is cooled at least in sections so that a structure with a second hardness is formed within the flat product at least in sections, the second hardness having a higher level of hardness in comparison to the structure with the first hardness. The heating and the cooling down of the flat product are coordinated with each other such that the structure with the second hardness is formed across the thickness of the flat product and at least in one of said sections, the structure with the first hardness remains constant across the thickness of the flat product.

Abstract: The invention relates to a method for joining a composite sheet to a metallic substrate, wherein the composite sheet has at least one metallic top layer and at least one non-metallic layer which consists of a plastic material, wherein an opening is introduced into the composite sheet, and wherein at least one joining element is provided which is inserted into the opening of the composite sheet. A method for joining a composite sheet to a metallic substrate with process reliability and of specifying a corresponding structure is achieved by forming the joining element as a metallic sleeve, wherein the metallic sleeve is deformed, so that it joins together with the composite sheet in a form-fit and force-fit manner, and wherein the metallic sleeve is firmly bonded to the substrate with the end pointing towards the substrate using a filler material, wherein the filler material is arranged inside the sleeve.

Abstract: The invention relates to a method for joining a composite sheet to a metallic substrate, wherein the composite sheet has at least one metallic top layer and at least one non-metallic layer which consists of a plastic material, wherein an opening is introduced into the composite sheet, and wherein at least one joining element is provided which is inserted into the opening of the composite sheet. A method for joining a composite sheet to a metallic substrate with process reliability and of specifying a corresponding structure is achieved by forming the joining element as a metallic sleeve, wherein the metallic sleeve is deformed, so that it joins together with the composite sheet in a form-fit and force-fit manner, and wherein the metallic sleeve is firmly bonded to the substrate with the end pointing towards the substrate using a filler material, wherein the filler material is arranged inside the sleeve.

Abstract: A method for welding a first workpiece with a joining element, wherein the joining element and the first workpiece consist at least partially of a metal, includes moving the joining element relative to the first workpiece during welding and at the same time pressing the joining element against the first workpiece. This method for welding a joining element with a material permits a reliable firmly-bonded connection between joining element and workpiece, when the workpiece consists of a composite material or has low rigidity, and is achieved by generating an electrical current between workpiece and joining element during mechanical contact of the joining element with the first workpiece.

Abstract: A method for welding a first workpiece with a joining element, wherein the joining element and the first workpiece consist at least partially of a metal, includes moving the joining element relative to the first workpiece during welding and at the same time pressing the joining element against the first workpiece. This method for welding a joining element with a material permits a reliable firmly-bonded connection between joining element and workpiece, when the workpiece consists of a composite material or has low rigidity, and is achieved by generating an electrical current between workpiece and joining element during mechanical contact of the joining element with the first workpiece.