A method for improving the wear resistance of the valve disc cone surface and reducing the surface roughness

Abstract

The invention provides a method for improving the wear resistance of the cone surface of the valve disc and reducing the surface roughness. A layer of dense chilled layer is formed on the cone surface by external force forging. The hardness of the chilled layer is higher than that of The base body is 4-8 units higher than HRC, and the thickness of the hardened layer is 1.5-2.0mm, which improves the wear resistance of the valve disc cone surface, and at the same time presses the microscopic wave peaks and troughs on the disc cone surface through the mirror forging die Flat, improving the smoothness of the disc cone surface, the surface roughness of the disc cone surface can be reduced to below Ra0.15, close to the mirror surface requirements, thus improving the sealing performance of the valve disc cone surface and avoiding the wear and tear of the valve disc cone surface Potential risks, improve product reliability.

Description

technical field [0001] The invention relates to the technical field of manufacturing internal combustion engine components, in particular to a method for improving the wear resistance of the conical surface of a valve disc and reducing the surface roughness. Background technique [0002] The role of the valve is to input air into the engine and discharge the exhaust gas after combustion. It is divided into intake valve and exhaust valve. The function of the intake valve is to suck air into the engine and mix it with fuel for combustion. The exhaust gas after combustion is discharged and dissipated. [0003] The valve and the valve seat or the valve seat ring are sealed by the cone surface, and the angle between the valve cone surface and the valve top surface is called the valve cone angle. The valve cone angle of the intake and exhaust valves is generally 45°, and only a few engines have an intake valve cone angle of 30°. The valve adopts a tapered working surface to obta...

AI Technical Summary

Problems solved by technology

[0006] In order to improve the wear resistance of the valve disc cone surface, the current treatment methods for the valve disc cone surface are: 1. The disc cone surface is quenched, and the hardness is generally around HRC45. Since the intake valve is mostly made of martensitic material, this method only It is used in intake valves and exhaust valves are mostly austenitic materials, which cannot be applied and has limitations; 2. Surfacing alloys on the disc and cone surfaces. There will be a large tensile stress during fusion, and this tensile stress will crack or fall off under complex working conditions in the engine

[0007] Furthermore, since the material of the valve is alloy steel, the toughness of this alloy steel material is relatively good, and the shedding of the grinding wheel during processing is likely to cause surface roughness, so the current processing method is likely to cause the surface roughness of the valve cone surface to be relatively large, which is difficult to To achieve a finish close to the mirror surface, a large surface roughness means that there are tiny peaks and troughs on the valve cone surface that are invisible to the naked eye, which is likely to cause air leakage and cause the valve cone surface to be less tight

Images