Patent ID: 8616161

Claim:
Method for the production of a piston ( 10 ) for an internal combustion engine, having a circumferential cooling channel ( 24 ), whereby a blank ( 11 â€²) of a lower piston part ( 11 ) is forged, and a blank ( 12 â€²) of an upper piston part ( 12 ) is produced, the blanks ( 11 â€², 12 â€²) are pre-machined and joined together to form a piston blank ( 10 â€²), which is finished to produce the piston ( 10 ), wherein the lower piston part ( 11 ) forms a circumferential ring belt ( 22 ) and a combustion chamber bowl ( 23 ), wherein said circumferential cooling channel ( 24 ) is positioned between said ring belt ( 22 ) and said combustion chamber bowl ( 23 ), wherein at least one depression ( 25 ) is formed into the blank ( 11 â€²) of the lower piston part ( 11 ) during the forging process, wherein a circumferential lower cooling channel ( 24 a ) is worked in during pre-machining of the blank ( 11 â€²) of the lower piston part ( 11 ), in such a manner that the at least one depression ( 25 ) is exposed and an opening ( 33 ) for a coolant inflow and/or a coolant outflow is formed.