Gasoline engine piston expansion ring and preparation method thereof

Abstract

The invention provides a gasoline engine piston expansion ring and a preparation method thereof. In order to keep the expansion ring elastic at high temperature, use iron powder, graphite, ferrosilicon powder, ferromanganese powder, etc. to prepare matrix components, add graphite, MoS2, CaF2 as lubricant, and add WC, TiC, VC, Cr3C2 as hard phase Improve the wear resistance, add V and Mo as alloy elements to improve the high temperature performance of the expansion ring, add Cu powder to improve the heat dissipation performance of the expansion ring, and prepare the expansion ring through powder mixing, pressing, sintering, grinding, and opening. This method can produce expanded rings in near-net shape, and only needs simple grinding and opening treatment after sintering. The process is short and the cost is low; there are no casting defects such as porosity, shrinkage cavity, composition segregation, and coarse lamellar structure. Uniform and fine microstructure, easy to add alloy elements, lubricating components, hard phase particles, excellent performance; in addition, the process has high stability and repeatability, and can realize batch continuous production.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and particularly provides a method for preparing a gasoline engine piston expansion ring. technical background [0002] The piston expansion ring is a metal elastic ring with a cut, commonly known as a piston ring. When working, the expansion ring is pressed against one side of the expansion ring groove by the pressure of the working medium, and the outer cylindrical surface of the expansion ring and the close-fitting end face jointly play a sealing role. Expanding rings are mainly used for piston seals of reciprocating compressors and internal combustion engines with high operating temperatures, and shaft seals of steam turbines. [0003] At present, there are two methods of preparing expansion rings: casting and machining. When using the casting process to produce expansion rings, cast iron is usually used as the material. This process has the problems of many processes, low yield, a...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two methods of preparing expansion rings: casting and machining. When using the casting process to produce expansion rings, cast iron is usually used as the material. This process has the problems of many processes, low yield, and high cost, and cast iron is not durable. Grinding; when the machining process is used, 65Mn forging machine materials are mostly used, and after machining processes such as turning and milling, however, since the elastic expansion ring is a thin-walled multi-notch part, there are problems in the cold / hot processing process. Factors such as various stresses and improper clamping of the workpiece cause serious deformation of the elastic expansion ring, and the scrap rate is as high as 70%~80%, which greatly increases the manufacturing cost