METHOD FOR MANUFACTURING PISTON WITH RE-MOLTEN REINFORCED COMBUSTION CHAMBER THROAT

摘要

A method for manufacturing a piston with a re-molten reinforced combustion chamber throat. A material of the piston is an aluminum alloy or a magnesium alloy. The manufacturing steps comprises: a) piston rough machining: the combustion chamber throat and the combustion chamber bottom of the piston are the weakest parts of the piston, and machining allowances of the combustion chamber throat and the combustion chamber bottom are 1-3mm; b) piston washing and degreasing treatment; c) coating or spraying a surfactant on the combustion chamber throat and the combustion chamber bottom that need to be re-molten, wherein the surfactant formula comprises the components TiO2, SiO2, CuCl2 and MnCl2 that are mixed in percentage: 1-30% of TiO2, 1-30% of SiO2, 1-40% of CuCl2 and 1-50% of MnCl2; after the four components are uniformly mixed, a suspension liquid is prepared by using acetone as a solvent according to a mass ratio of 1: (3-8); d) re-melting the piston by using an A-TIG welding method; and f) after re-melting, processing the piston into a finished product. After re-melting treatment, the microscopic structure of the aluminum alloy is obviously changed, and the microscopic hardness in the re-molten zone is about 1.2-2.0 times of the hardness of the piston body. The method helps to improve the anti-fatigue capability of the aluminum alloy material, namely, the throat part.