Method for strengthening engine valve and engine valve

Abstract

The invention discloses a method for strengthening an engine valve and an engine valve. The method for strengthening an engine valve includes the following steps: step S1, the initial engine valve blank undergoes electrothermal upsetting to obtain a first engine valve blank; step S2, the first engine valve blank The conical surface and neck of the blank are hot stamped to obtain a second engine valve blank; step S3, cooling the second engine valve blank to room temperature, and then performing solution treatment on the cooled second engine valve blank; step S4, the second engine valve blank The conical surface and neck of the second engine valve blank are subjected to severe plastic deformation treatment to obtain the third engine valve blank; step S5, the third engine valve blank is subjected to aging treatment to obtain the engine valve; the present invention obtains the engine valve through the conical surface and the neck of the engine valve It has been strengthened. Compared with the existing conical surface surfacing technology or surface nitriding treatment, the engine valve can obtain a surface with higher hardness, fine grain and compressive stress.

Description

technical field [0001] The invention relates to the field of engine valves, in particular to an engine valve strengthening method and the engine valve. Background technique [0002] In order to meet the ever-increasing environmental protection requirements of motor vehicles, the engine is gradually developing towards higher explosion pressure and combustion temperature. Among them, the wear resistance, high temperature resistance and corrosion resistance of the directly affected engine valves, as well as the mechanical and fatigue strength are proposed. higher requirements. The engine valve cone and engine valve neck have the most complicated working conditions, which are affected by alternating loads, high temperatures, friction and wear, etc., so it is necessary to further improve the comprehensive performance of the engine valve cone and neck. [0003] In order to meet the performance requirements of modern diesel engines, the heads of many engine valves are made of high...

AI Technical Summary

Problems solved by technology

The former has high manufacturing costs, and there are some surfacing problems, such as surfacing cracks, surfacing pores, surfacing stress, etc.; the latter is mainly through chemical heat treatment methods such as nitriding, carburizing or nitrocarburizing. Strengthening, keeping the core hardness unchanged, can greatly improve the surface hardness (the surface hardness of austenitic steel reaches 800HV after nitriding, and the carburized surface hardness is about 600HV), and the wear resistance is also greatly improved. The characteristics of stainless steel and nickel-based alloy materials determine that the hardening depth of chemical heat treatment is relatively shallow, usually the surface depth is only a dozen microns, and its effective wear-resistant surface is thin, which is often worn away during use, so that it cannot reach Required service life

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