Method for the production of a piston for an internal combustion engine

A method for the production of a piston for an internal combustion engine, comprising the following steps:

• producing an upper piston part made of steel by forging, the upper piston part having a piston crown having a combustion bowl, a ring wall formed onto the piston crown radially on an outside, directed downward, and a ring-shaped support disposed radially within the ring wall formed onto an underside of the piston crown, wherein an upper part of a cooling channel is formed between the ring wall and the support,
• producing a lower piston part made of steel by forging or casting, the lower piston part having two skirt elements that lie opposite one another, which are connected with one another by way of two pin bosses that lie opposite one another, a ring-shaped contact part disposed on a top of the lower piston part and connected with the pin boss, and a circumferential ring rib disposed radially outside of the contact part and connected with the skirt elements, wherein a lower part of the cooling channel is formed between the contact part and the ring rib,
• welding the upper piston part to the lower piston part by way of contact surfaces of the ring wall and the ring rib, and of the support and the contact part, respectively, wherein the cooling channel formed by the upper piston part and by the lower piston part is closed, and
• finishing the piston using a chip-cutting production method,
• wherein during the step of producing the upper piston part, an upper piston part blank is pre-formed using a semi-hot-forming method, at 600° C. to 900° C., after which the upper piston part blank is cold-formed at 0° C. to 150° C., after which the combustion bowl and/or the upper part of the cooling channel undergo no further processing, and subsequently a radially outer region of the piston crown, a radially outer region of the ring wall, a lower region of the inner surface of the ring wall, and the contact surface of the support of the upper piston blank are finished to produce the upper piston part.

A method for the production of a piston for an internal combustion engine, comprising the following steps:

• producing an upper piston part made of steel by forging, the upper piston part having a combustion bowl, a ring wall formed onto the piston crown radially on an outside, directed downward, and a ring-shaped support disposed radially within the ring wall formed onto an underside of the piston crown, wherein an upper part of a cooling channel is formed between the ring wall and the support,
• producing a lower piston part made of steel by forging or casting, the lower piston part having two skirt elements that lie opposite one another, which are connected with one another by way of two pin bosses that lie opposite one another, a ring-shaped contact part disposed on a top of the lower piston part and connected with the pin boss, and a circumferential ring rib disposed radially outside of the contact part and connected with the skirt elements, wherein a lower part of the cooling channel is formed between the contact part and the ring rib,
• welding of upper piston part to the lower piston part by way of contact surfaces of the ring wall, and the ring rib, and of the support and the contact part, respectively, wherein the cooling channel formed by the upper piston part and by the lower piston part is closed, and
• finishing the piston using a chip-cutting production method,
• wherein during the step of producing the upper piston part, an upper piston part blank is cold-formed at 0° C. to 150° C., after which the combustion bowl and/or the upper part of the cooling channel undergo no further processing, and subsequently a radially outer region of the piston crown, a radially outer region of the ring wall, a lower region of an inner surface of the ring wall, and the contact surface of the support of the upper piston blank are finished to produce the upper piston part.