A steel piston based on laser welding forming inner cooling oil passage and its processing method

Abstract

The invention discloses a steel piston forming an inner cooling oil way based on laser welding and a machining method of the steel piston. The steel piston comprise a piston body and an annular sealing plate; a piston head part of the piston body is provided with the inner cooling oil way and a combustion chamber; the inner cooling oil way surrounds the combustion chamber, and the piston head part is further provided with an oil inlet hole and an oil outlet hole which communicate with the inner cooling oil way; an annular opening is formed in the upper end of the inner cooling oil way and located in the top end of the piston head part; the annular sealing plate is embedded in the annular opening and connected and fixed through laser welding, the upper end of the inner cooling oil way is sealed, an inner annular channel is formed by the inner circle of the annular sealing plate and the side wall of the annular opening in a surrounding manner, an outer annular channel is formed by the outer circle of the annular sealing plate and the side wall of the annular opening in a surrounding manner, and the inner annular channel and the outer annular channel are filled with high-temperature-resisting heat isolation rings used for forming a laser welding pool. The method comprises the first step of component machining, the second step of laser welding and assembling, the third step of heat treatment and the fourth step of post machining. The steel piston and the machining method have the beneficial effects of being high in machining cost, good in quality stability and low in machining cost.

Description

technical field [0001] The invention relates to a steel piston and a processing technology thereof, in particular to a steel piston formed on the basis of laser welding to form an internal cooling oil passage and a processing method thereof. Background technique [0002] For the emission upgrade of vehicle diesel engines, the piston is a key component. Steel structure pistons replace aluminum structure pistons, which is one of the important means for vehicle diesel engines to meet Euro IV, Euro V, and Euro VI emission standards. In recent years, all-steel pistons have been widely used in vehicle diesel engines. All-steel pistons are forged, but the inner cooling oil cavity of all-steel pistons is poorly processed, difficult to process, low in efficiency and high in cost. Around the molding of the internal cooling oil cavity, there are various solutions at home and abroad, such as the method for manufacturing the integral piston of the internal combustion engine disclosed by ...

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Problems solved by technology

However, there are also the following deficiencies: first, the residue of the friction welding flash in the internal cooling oil channel is relatively large, which affects the cooling effect, and also increases the weight of the piston head, which affects the performance of the piston; the second is that the friction welding axial control tolerance Limitation (axial tolerance ±0.25mm), the effective height of the internal cooling oil chamber has a large tolerance, which affects the control of the axial dimension of the piston head; the third is that there are process defects in the open trapezoidal welding surface. In the first stage, the upsetting force loading is limited by the open trapezoidal welding surface. Excessive loading will lead to deformation of the welding surface. If the upsetting force is insufficient, the quality of the welded joint formed after the solid phase connection of the weld will be unreliable.

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