Abstract: A low-alloyed steel, comprising about 0.3 to about 0.50 wt. % carbon, about 2.0 to about 5.0 wt. % silicon, and a remainder of iron, optionally containing low amounts of molybdenum, titanium and/or boron, with up to about 0.5 wt. % impurities. The low-alloyed steel is useful for making structural components having a tensile strength of greater than about 1000 to about 2000 MPa, a yield strength of greater than about 700 to approximately 950 MPa; a break elongation of greater than about 17% and a scaling resistance of greater than about 650° C.

Abstract: A method for producing a rotationally symmetrical hollow metal part, particularly a shaft. According to the method, bar-shaped ductile solid material is provided, the solid material is heated from about 300° C. below the forging temperature to the forging temperature, the solid material is transversally spline-rolled until weakenings are created in the core zone (3) of the solid material and the sold material is torn open. Two mandrels (5,6) are forcibly introduced into the center of the bar-shaped solid material during the rolling process, and then one mandrel is retracted while the other mandrel continues advancing so as to produce a tubular part. A transversally spline-rolled rotationally symmetrical hollow part, especially a shaft, which is produced according to noted method can be embodied as a transmission shaft, camshaft, drive shaft, output shaft, starter shaft, hollow shaft, or can be a preform for molded parts and the like.

Abstract: A device and method are provided for forging sleeve-shaped parts such as pistons. The device includes a form with: an upper form mandrel (C); an outer form ring (A); a lower form mandrel (B); an ejector device with an upper ejector (G) for ejection through the upper form mandrel (C); a lower ejector (H) for ejection through the lower form mandrel (B). Optional support devices for the form include a lower reinforcement ring (D) for the lower region of the outer form ring (A), a form mandrel housing (F) for the upper region of the outer form ring (A), and a clamping base (E) to support the lower form mandrel (B), by means of which the lower ejector (H) may be operated. The device and method advantageously facilitates the manufacture of pistons having a long skirt length and a minimal wall thickness.

Abstract: A method of friction welding a head part to a skirt part of a piston having a hollow cooling duct in which the internal connection surface of the first part to be welded is reciprocally arranged with an internal connection surface of the second part to be friction welded, so that they form a unsymmetrical contact area, so that the resulting weld of the first and the second parts produces a weld bead that is located predominantly outside of the hollow cooling duct. The unsymmetrical contact area can be formed by chamfered, angled edge surfaces that produce, for example, a wedge-shaped space, or partially matched, inter-fitting surfaces that remain out of contact and produce a gap at sides facing the hollow space.

Abstract: A method of friction welding a head part to a skirt part of a piston having a hollow cooling duct in which the internal connection surface of the first part to be welded is reciprocally arranged with an internal connection surface of the second part to be friction welded, so that they form a unsymmetrical contact area, so that the resulting weld of the first and the second parts produces a weld bead that is located predominantly outside of the hollow cooling duct. The unsymmetrical contact area can be formed by chamfered, angled edge surfaces that produce, for example, a wedge-shaped space, or partially matched, inter-fitting surfaces that remain out of contact and produce a gap at sides facing the hollow space.

Abstract: A cooling channel piston for an internal combustion engine which includes a piston bottom and a piston shaft that are joined thereto of a friction welding process. The piston bottom and the piston shaft jointly form a cooling channel. An annular wall which radially delimits the cooling channel towards the outside is formed by the piston bottom and/or the piston shaft. The annular wall can be sealed by a welding process once the piston bottom and the piston shaft have been joined together.

Abstract: A method for producing a rotationally symmetrical hollow metal part, particularly a shaft. According to the method, bar-shaped ductile solid matrial is provided, the solid material is heated from about 300° C. below the forging temperature to the forging temperature, the solid material is transversally spline-rolled until weakenings are created in the core zone (3) of the solid material and the sold material is torn open. Two mandrels (5,6) are forcibly introduced into the center of the bar-shaped solid material during the rolling process, and then one mandrel is retracted while the other mandrel continues advancing so as to produce a tubular part. A transversally spline-rolled rotationally symmetrical hollow part, especially a shaft, which is produced accoridng to noted method can be embodied as a transmission shaft, camshaft, drive shaft, output shaft, starter shaft, hollow shaft, or can bea preform for molded parts and the like.

Abstract: A device and method are provided for forging sleeve-shaped parts such as pistons. The device includes a form with: an upper form mandrel (C); an outer form ring (A); a lower form mandrel (B); an ejector device with an upper ejector (G) for ejection through the upper form mandrel (C); a lower ejector (H) for ejection through the lower form mandrel (B). Optional support devices for the form include a lower reinforcement ring (D) for the lower region of the outer form ring (A), a form mandrel housing (F) for the upper region of the outer form ring (A), and a clamping base (E) to support the lower form mandrel (B), by means of which the lower ejector (H) may be operated. The device and method advantageously facilitates the manufacture of pistons having a long skirt length and a minimal wall thickness.

Abstract: A method of friction welding a first part to a second part of a component having a hollow space in which the internal connection surface of the first part to be welded is reciprocally arranged with an internal connection surface of the second part to be friction welded, so that they form a unsymmetrical contact area, so that the resulting weld of the first and the second parts produces a weld bead that is located predominantly outside of the hollow space. The unsymmetrical contact area can be formed by a chamfer, angled edge surfaces that produce, for example, a wedge-shaped space, or partially matched, inter-fitting surfaces that remain out of contact at sides facing the hollow space.