Process formula and method of high-strength gray cast iron casting

Abstract

The invention discloses a process formula and method of a high-strength gray cast iron casting. The high-strength gray cast iron casting is prepared from the following raw material components in percentage by weight: 2.8-3.0% of carbon, 1.7-1.9% of silicon, 0.8-1.0% of manganese, 0.1-0.2% of chromium, 0.3-0.5% of copper, 0.06-0.1% of tin, 0.01-0.05% of nickel, 0.01-0.03% of titanium, 0.005-0.02% of vanadium and the balance of iron, wherein the proportion of the components is percent by weight based on the chemical purity content. According to the process formula and method, the technical understanding of a traditional casting is broken through, trace alloy elements are added during low carbon silicon equivalent, the comprehensive mechanical properties of the casting is improved, high pearlite content is maintained, and a foundation is laid for forming an ideal compound layer for subsequent surface chemical heat treatment.

Description

technical field [0001] The invention relates to a manufacturing method of a metal casting, in particular to a manufacturing method for improving the service life of a workpiece through nitrocarburizing treatment of gray cast iron friction pair parts in the later stage, specifically a technical formula and a method of a high-strength gray iron casting. Background technique [0002] High-pressure plunger pump is the most important core component of construction machinery excavator, which is composed of pump body, swash plate bracket, plunger, cylinder block, etc. The flange and the swash plate bracket are one of the most important pair of friction pairs. Generally, different metal materials are selected according to different partners, and materials such as ductile iron and gray cast iron are often used in consideration of manufacturing costs and product working life characteristics; because The working pressure of the high-pressure hydraulic pump is usually above 30MPa, and t...

AI Technical Summary

Problems solved by technology

In actual production, it is difficult to achieve the above-mentioned mechanical properties, chemical composition and metallographic structure of flange castings with a wall thickness of more than 30 mm, especially high-end castings after finishing with nitrogen-carbon surface chemical heat treatment, hardness and deformation requirements are relatively high; however Since carbon and silicon elements hinder the infiltration of active nitrogen atoms and lack elements combined with nitrogen atoms, the carbon and silicon content of castings should be as low as possible to meet the requirements of the casting process. At the same time, trace alloy elements are added to change the compound layer structure, but the casting Low carbon and silicon content is easy to form carbides and shrinkage cavities, and the performance of the core of the casting is seriously reduced due to the thick wall thickness

In order to eliminate the above unfavorable factors, it is usually used to add trace amounts of Cu, Sn, Cr and other alloying elements to change and refine graphite to a certain extent, control the quantity and shape of ferrite, pearlite is also refined, and ferrite in the matrix Solid solution strengthening is obtained due to the action of trace alloying elements. Microalloying improves the strength of cast iron and improves the microstructure of the material. However, if the addition of Sn and Cr is too large, the shrinkage porosity inside the casting tends to increase.