Abstract: An apparatus for the exact positioning and fastening of several parts, which have an opening, onto a hollow body, whereby, in the initial state, the opening of said parts, which are to be fastened, is larger than the dimensions of the respective fastening positions of the hollow body. Before the fastening process is carried out by hydraulically expanding the hollow body, the parts are positioned at the respective fastening positions of the hollow body by placing the parts into the depressions of a mold, which comprises at least two parts. The hydraulic fluid is introduced into the hollow body via an inlet element, which is attached to the mold. To prevent leakage of the fluid and contamination of the workpiece, there is an expandable elastic container for the hydraulic fluid, disposed at the inlet element, which adjoins to one end of the hollow body. The container is inserted into the hollow body and is held by a support on its free face.

Abstract: A method of producing a cam shaft or a similar member that has a core pipe upon which are secured, via expansion of the core pipe, components that are spaced from one another and have a precribed position on the core pipe, with the expansion of the core pipe being effected by introducing a hydraulic fluid into the core pipe. The surface of the components that are secured on the core pipe and are made of a ductile spheroidal graphite iron or sintered material, are subjected to a mechanical abrasion and are melted via a controlled laser beam in such a way as to first slightly reduce the adhesive pressure betewwn the components and the core pipe as a consequence of the melting of the surface layer, and subsequently, after hardening of the melted layer and due to temperature equalization in the components and the core pipe, to increase the adhesive pressure to a higher value. The melting results in a ledeburitic structure having an adequate depth.

Abstract: A method and apparatus for securing one or more parts, each of which is provided with an opening, to a hollow member. In the starting state, the inner diameter of the opening of the parts is greater than the outer diameter of the surface provided on the hollow member for securing the part. The parts are placed in the prescribed position on the hollow member prior to the securing operation. In order in a simple and economical manner to reliably secure the parts to the hollow member without the danger of overstressing the latter, and without the danger that the parts will loosen, a temperature difference is produced, prior to placing the parts on the hollow member, by heating the parts and/or by cooling the hollow member. Subsequently, each part is secured to the hollow member by widening the latter at least in the securing regions thereof, and by a subsequent shrink fitting of the parts onto the hollow member as a consequence of the temperature equalization that occurs.

Abstract: An apparatus for securing straight tubes between two tube sheets in a pressure-tight manner, especially in the manufacture of heat exchangers. Tubes are inserted, with play, in bores of the tube sheets. One end of each tube is hydraulically expanded via a pressure medium to thereby press this one end against the associated tube sheet. The one end is secured to the associated tube sheet, preferably by being welded thereto. Each tube is heated in conformity with a prescribed prestress that is to be produced in secured ones of the tube to take into account subsequent operation conditions to push a portion of the non-secured other end of the tube out of its associated tube sheet until a predetermined difference in length between the cold and heated-up states of the tube is pushed out.

Abstract: A method and apparatus for securing straight tubes between two tube sheets in a pressure-tight manner, especially in the manufacture of heat exchangers. Tubes are inserted, with play, in bores of the tube sheets. One end of each tube is hydraulically expanded via a pressure medium to thereby press this one end against the associated tube sheet. The one end is secured to the associated tube sheet, preferably by being welded thereto. Each tube is heated in conformity with a prescribed prestress that is to be produced in secured ones of the tube to take into account subsequent operating conditions to push a portion of the non-secured other end of the tube out of its associated tube sheet until a predetermined difference in length between the cold and heated-up states of the tube is pushed out.

Abstract: A method of securing tubes between tube sheets of a heat exchanger, with the tube sheets being interconnected via a housing. The tubes and/or the tube sheets of are made of a steel that has to be annealed after a welding process. To be able to provide a stress-free connection between the tubes and the tube sheets, and to enable simple repair of the tubes, the length of at least one end of each tube is extended by welding thereto a tubular piece that is made of a material that can be welded without subsequent thermal treatment being required. Sleeves that extend the length of the holes in the tube sheet are welded onto the outer surface of at least one of the tube sheets. At least the free end of each sleeve is made of a material that can be welded without subsequent thermal treatment being required. One end of each tube, if such end is not provided with a tubular extension, is welded onto a tube sheet.