Abstract: A casting tool for a piston may include a casting mold for forming a piston part from a casting melt and a casting head including a feeder for feeding the casting melt into the casting mold. The casting head may include a ring-shaped groove, and the groove may include an inner groove flank for forming the casting melt into a circumferential, ring-shaped sealing rib such that an inner rib flank of the sealing rib rests with a sealing effect against the inner groove flank when the casting melt solidifies in the groove. Additionally or alternatively, the casting head may include a ring-shaped collar, and the collar may include an outer collar flank for forming the casting melt to provide a circumferential, ring-shaped sealing groove such that an outer groove flank of the sealing groove rests with a sealing effect against the outer collar flank when the casting melt solidifies.

Abstract: A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

Abstract: An insert part for a cast piston of an internal combustion engine may include a powder, such as a sintered powder material, containing at least iron or alloys thereof, and having a capacity for being infiltrated. The powder may contain particles having different grain sizes, and up to 4% by volume of the powder may include particles having a diameter smaller than 75 ?m.

Abstract: A casting tool for a piston may include a casting mold for forming a piston part from a casting melt and a casting head including a feeder for feeding the casting melt into the casting mold. The casting head may include a ring-shaped groove, and the groove may include an inner groove flank for forming the casting melt into a circumferential, ring-shaped sealing rib such that an inner rib flank of the sealing rib rests with a sealing effect against the inner groove flank when the casting melt solidifies in the groove. Additionally or alternatively, the casting head may include a ring-shaped collar, and the collar may include an outer collar flank for forming the casting melt to provide a circumferential, ring-shaped sealing groove such that an outer groove flank of the sealing groove rests with a sealing effect against the outer collar flank when the casting melt solidifies.

Abstract: A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

Abstract: A method for producing a piston with a combustion bowl may include fastening an annular fibrous preform for reinforcing a periphery of the combustion bowl in a casting mold for the piston coaxially with a piston axis in a plane of a piston head. The method may also include introducing a metal melt into the casting mold to produce a piston blank, generating a pressure difference between the metal melt and the fibrous preform for infiltration of the metal melt into the fibrous preform, and machining the piston blank. The fibrous preform may be held in the casting mold by suction tubes in which a negative pressure may prevail such that the metal melt may be sucked into and infiltrate the fibrous preform. At least one section of at least one of the suction tubes may accelerate solidification of the metal melt passing into the suction tube.

Abstract: An insert part for a cast piston of an internal combustion engine may include a powder, such as a sintered powder material, containing at least iron or alloys thereof, and having a capacity for being infiltrated. The powder may contain particles having different grain sizes, and up to 4% by volume of the powder may include particles having a diameter smaller than 75 ?m.

Abstract: A piston for an internal combustion engine including a piston crown having an upper surface and a lower surface; a piston skirt; and a generally cup-shaped undercrown formed on the lower surface of the piston crown and integral with the top portions of opposing side walls of the piston skirt, at least a portion of the surface of the undercrown being rough, defining at least one region of increased surface area, wherein the distance between an uppermost and lowermost points of the surface of the undercrown in the at least one region of increased surface area is in the range of approximately 0.1 mm to 1.0 mm.