Machining method of friction welding of forged steel piston

Abstract

The invention provides a machining method of friction welding of a forged steel piston. The concrete steps are as follows: (1) dividing the steel piston into a piston head and a piston skirt which are respectively machined to be semi-finished products, wherein the shape of an inner cooling oil channel, an oil inlet and an oil outlet of the piston head and the piston skirt are machined to be in the sizes of a finished product, clearance of 1.5-4mm is reserved in the height direction, and a gap is reserved in the position, on one side of the inner-cooling oil channel, on the welding surface of the piston head and the piston skirt; and (2) combining the piston head and the piston skirt into a whole through the friction welding, wherein the gap is right filled with the turnup edge of a friction welding seam, and then carrying out other machining on the piston. The turnup edge is prevented from occurring on the inner side of the cooling oil channel, cooling effect of cooling oil on the top of the piston can not be affected, no turnup edges exist in the inner cooling oil channel, the weight of the piston can be reduced, the load of a connecting rod mechanism can be lightened, due to the fact that the turnup edge is embedded, the phenomenon that the inner turnup edge is scoured by the cooling oil to fall off to form hard particles, and risks including engine scraping and the like are caused is avoided.

Description

technical field [0001] The invention relates to a processing method of a friction welding forged steel piston, which is suitable for high horsepower and high load vehicle and marine engine steel pistons. Background technique [0002] In order to meet the requirement of increasing the explosion pressure of Euro V and Euro VI emission engines to above 20MPa, and the traditional aluminum piston has reached the limit of use, steel pistons must be used. [0003] like figure 1 Shown is the existing friction welded forged steel piston, which is divided into a steel piston head 1 and a steel piston skirt 2. The steel piston head 1 and the steel piston skirt 2 are combined by friction welding to form a piston The internal cooling oil passage 4 is a common method for all-steel pistons at present, but this process makes the flange 4 of the friction welding seam occupy a large amount of space in the cooling oil passage. The friction welding flanging in the cooling oil passage will lea...

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Problems solved by technology

[0003] like figure 1 Shown is the existing friction welded forged steel piston, which is divided into a steel piston head 1 and a steel piston skirt 2. The steel piston head 1 and the steel piston skirt 2 are combined by friction welding to form a piston The internal cooling oil passage 4 is a common method for all-steel pistons at present, but this process makes the flange 4 of the friction weld occupy a large amount of space in the cooling oil passage

The friction welding flanging in the cooling oil passage will lead to the following serious problems: (1) Reduce the fluidity of the cooling oil in the inner cavity during operation, thereby reducing the cooling effect and increasing the risk of piston burning and cracking when the engine is working; (2) When the engine is working, the inner flanging falls off under the impact of high-pressure oil, forming hard particles, which will wear the key parts of the engine cylinder, reduce the engine power and worsen the emission

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