Abstract: A method and a manufacturing line allow for the manufacture of piston blanks of dimensions close to the final dimensions, which in the course of subsequent finish-machining need only be machined with removal of material to a small degree. A piston shaft of the piston blank is produced by backward extrusion. At least one hollow throat element is already produced at the piston blank by an upset-forging operation. For this purpose, a special forging tool is provided, which, after the manufacture of the piston shaft, takes effect on the piston blank in such a way that at least one hollow throat element is formed at the latest at subsequent forming of the piston base. In this way, a perceptible reduction is achieved in the weight of a piston in relation to conventionally manufactured forging pistons.

Abstract: A method for producing a piston for internal combustion engines includes the following steps: a first part is pre-fabricated by hot forging and a recess which has an undercut is formed in the first part during pre-fabrication by forming on the first part a projection, to which projection a lateral force is applied to form the undercut; a second part is pre-fabricated by hot forging and a projection is formed on this second part whose dimensions are matched to the dimensions of the recess; the two parts are joined together so that the projection on one part engages in the recess in the other part; and a compressive force is applied to the two parts which is sufficiently large and so aligned that the material of the projection on one part flows into the recess in the other part and completely fills it to connect the parts by positive fit.

Abstract: A piston for an internal-combustion engine is made up of a first part and a second part. One of the two parts forms the piston head and the other part forms the piston skirt. A cooling chamber, which is delimited by material of the first part and by material of the second part, is configured in the piston. The two parts are joined together positively and non-positively via a press fit formed by a projection of the second part, with the projection engaging with a recess in the first part.

Abstract: A method for producing a piston for internal combustion engines includes the following steps: a first part is pre-fabricated by hot forging and a recess which has an undercut is formed in the first part during pre-fabrication by forming on the first part a projection, to which projection a lateral force is applied to form the undercut; a second part is pre-fabricated by hot forging and a projection is formed on this second part whose dimensions are matched to the dimensions of the recess; the two parts are joined together so that the projection on one part engages in the recess in the other part; and a compressive force is applied to the two parts which is sufficiently large and so aligned that the material of the projection on one part flows into the recess in the other part and completely fills it to connect the parts by positive fit.

Abstract: A method for producing a piston for internal combustion engines includes the following steps: a first part is pre-fabricated by hot forging and a recess which has an undercut is formed in the first part during pre-fabrication by forming on the first part a projection, to which projection a lateral force is applied to form the undercut; a second part is pre-fabricated by hot forging and a projection is formed on this second part whose dimensions are matched to the dimensions of the recess; the two parts are joined together so that the projection on one part engages in the recess in the other part; and a compressive force is applied to the two parts which is sufficiently large and so aligned that the material of the projection on one part flows into the recess in the other part and completely fills it to connect the parts by positive fit.

Abstract: A method and a manufacturing line allow for the manufacture of piston blanks of dimensions close to the final dimensions, which in the course of subsequent finish-machining need only be machined with removal of material to a small degree. A piston shaft of the piston blank is produced by backward extrusion. At least one hollow throat element is already produced at the piston blank by an upset-forging operation. For this purpose, a special forging tool is provided, which, after the manufacture of the piston shaft, takes effect on the piston blank in such a way that at least one hollow throat element is formed at the latest at subsequent forming of the piston base. In this way, a perceptible reduction is achieved in the weight of a piston in relation to conventionally manufactured forging pistons.

Abstract: A method of manufacturing an entire piston, piston heads for example, especially intended for internal-combustion engines, wherein in an initial manufacturing step a blank that will eventually constitute the piston is preliminarily forged along a prescribed axis, shaping appropriate contours, and wherein in at least one subsequent manufacturing step the preliminarily shaped piston is finally forged along at least one other axis, creating additional contours.