Method for improving abrasion resistance of plate cone surface of valve and reducing surface roughness

Abstract

The invention provides a method for improving the abrasion resistance of the plate cone surface of a valve and reducing surface roughness. A cold and hard layer dense in structure is formed on the plate cone surface through external force forging, the hardness of the cold and hard layer is higher than that of a base body by four to eight units of HRC, the thickness of a hardened layer ranges from1.5 mm to 2.0 mm, and therefore the abrasion resistance of the plate cone surface of the valve is improved. Meanwhile, microcosmic wave crests and wave troughs on the plate cone surface are planishedthrough a mirror surface forging mold, the finish degree of the plate cone surface is improved, and the surface roughness of the plate cone surface can be reduced to Ra0.15 or below and is close to the mirror surface requirement; and therefore the sealing performance of the plate cone surface of the valve is improved, the potential risk of abrasion and cracking of the plate cone surface of the valve is avoided, and the reliability of the product is improved.

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

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