Patent ID: 8631572

Claim:
Method for the production of a piston for an internal combustion engine, having a ring-shaped cooling channel that lies radially on the outside, and a cooling chamber that lies in the center, comprising the following method steps: forging a piston blank ( 1 ), from which an upper piston part ( 5 ) and a lower piston part ( 6 ) are formed, separating the upper piston part ( 5 ) from the lower piston part ( 6 ), machining a piston part to form recesses ( 7 ′, 9 ′) for a ring-shaped cooling channel, welding the upper piston part ( 5 ) to the lower piston part ( 6 ), finish-machining the piston to produce piston ring grooves ( 32 , 33 , 34 ), pin bores ( 14 , 14 ′), and a combustion chamber bowl ( 28 ), wherein during forging of the piston blank ( 1 ), the top surface ( 2 ) of the piston blank ( 1 ) is partly given the shape of the underside of the upper piston part ( 5 ), during forging of the piston blank ( 1 ), the underside of the piston blank ( 1 ) is given a shape that corresponds to the interior ( 3 ) of the lower piston part ( 6 ), after forging of the piston blank ( 1 ) and before separation of the upper piston part ( 5 ) from the lower piston part ( 6 ), pin bores ( 14 , 14 ′) are introduced into regions of the piston blank ( 1 ) intended for the pin bosses ( 11 , 11 ′), and the top surface ( 2 ) of the piston blank ( 1 ) is given the finished shape of the underside of the upper piston part ( 5 ) by means of a cutting machining method, after separation of the upper piston part ( 5 ) from the lower piston part ( 6 ), and before welding of the upper piston part ( 5 ) to the lower piston part ( 6 ), the surface ( 26 ) of the lower piston part ( 6 ) on the piston crown side is finish-machined, and wherein during welding, the upper piston part ( 5 ) is welded to the lower piston part in an inverted orientation so that the top surface ( 2 ) of the piston blank ( 1 ) becomes the underside of the upper piston part.