Abstract: A method for manufacturing a bushing of a self-lubricating plunger includes: S1. uniformly mixing a base metal powder with a reinforcing metal powder to obtain a mixture, putting the mixture into a mold for pressing by a hydraulic press machine to form a blank, then sintering the blank to form a tubular metal foundation having a plurality of micropores; S2. melting a metal matrix lubricant by heating up, wherein the metal matrix lubricant includes a metal substance of low melting point and a basic lubricating powder dispersed in the metal substance, and the metal substance has a melting point higher than a storage temperature of the bushing and lower than a working temperature of the plunger; and S3. immersing the tubular metal foundation in the molten metal matrix lubricant to fill the micropores of the tubular metal foundation with the metal matrix lubricant, then cooling down the temperature.

Abstract: A lubricant for a copper alloy die-casting die is mainly prepared by an inorganic nano-powder, an organic substrate material, and an organic resin material. In the present disclosure, the use of oil-based lubricants as a basis and the reduction of the content of oil in the lubricant yield improved oil selection and proportion, which cooperates with the corresponding higher proportion of inorganic powder material mixture and a more suitable spraying amount applied on the surface of the die to exert a good lubricating effect on products with complex and irregular shapes in the inner cavity of a die-casting die. At the same time, the production cost of the lubricant is low. Copper alloy die castings produced after a lubrication process have a high yield rate and smooth surfaces without casting defects.

Abstract: A sand core structure for die-casting includes a positioning-filling rod and a sand core body configured to encompass the positioning-filling rod. The positioning-filling rod has a compressive strength greater than a compressive strength of the sand core body, and the positioning-filling rod is made of a breathable material.