Patent ID: 8286852
Filing Date: 2012-10-16
Classification: B23K,F02F

Abstract:
1. A method of friction welding of a piston having a cooling duct, a head member and a skirt member; wherein a hollow cooling duct is formed upon welding together of the head and skirt member; with the steps: providing a head member; providing a skirt member; chamfering at least one of the surfaces of contact areas of the parts of the head member and skirt member to be welded such that they do not match and provide a gap for receiving a welding bead produced by the friction welding when the parts are positioned opposite each other, said gap side facing into an area for forming the cooling duct, arranging the contact areas of the parts of the head member and skirt member to be welded so that an internal connection surface of the inner wall of the head member is reciprocally arranged with respect to an internal connection surface of an inner wall of the skirt member, and arranging an external connection surface of an outer wall of the head member relative to an outer wall of the skirt member so that said gap is formed between the internal connection surfaces of the head and skirt member before welding; and then, producing friction welded connections between said internal and external connection surfaces in a manner causing friction weld beads formed to be essentially contained within in the gap adjacent the cooling duct with essentially no weld beads protruding into the cooling duct so as to allow an undisturbed oil circulation through the cooling duct by causing the material accumulations of the welding process to form outside of the cooling duct.