Valve retainer and preparation process thereof

Abstract

The invention provides a valve retainer and a preparation process thereof. The preparation process comprises the following steps of: preparing powder, wherein the powder comprises high alloy layer powder and low alloy layer powder; carrying out compression moulding and sintering on the powder to prepare a valve retainer; carrying out cold treatment, heat treatment, cleaning and drying on the prepared valve retainer; carrying out deposition on a base surface of the valve retainer by adoption of a cathode arc deposition technology and magnetron sputtering technology combined manner so as to forma transition layer and a DLC coating; and finally annealing the valve retainer. By adoption of the preparation process, the valve retainer has relatively high heat stability, relatively high corrosion resistance and relatively low friction coefficient, so that the wear resistance, service life and system reliability of the valve retainer are effectively improved.

Description

technical field [0001] The invention mainly relates to a method for preparing engine cylinder head accessories, in particular to a valve seat ring and a preparation process thereof. Background technique [0002] This section provides background information related to the present disclosure only and is not necessarily prior art. [0003] The valve seat ring is located at the part where the cylinder head is combined with the valve cone surface. There is a corresponding cone surface. With continuous improvement, the high-speed impact and working stress between the valve and the valve seat ring are increasing, and the impact wear on the valve seat ring is becoming more and more serious. In addition, the valve seat ring in the prior art is often There are adhesive wear and corrosion wear. The so-called adhesive wear, also known as occlusal wear, refers to the local occurrence of metal adhesion on the contact surface of the friction pair during sliding friction, and the adhesion ...

AI Technical Summary

Problems solved by technology

[0003] The valve seat ring is located at the part where the cylinder head is combined with the valve cone surface. There is a corresponding cone surface. With continuous improvement, the high-speed impact and working stress between the valve and the valve seat ring are increasing, and the impact wear on the valve seat ring is becoming more and more serious. In addition, the valve seat ring in the prior art is often There are adhesive wear and corrosion wear. The so-called adhesive wear, also known as occlusal wear, refers to the local occurrence of metal adhesion on the contact surface of the friction pair during sliding friction, and the adhesion is destroyed in the subsequent relative sliding, and metal chips are removed from the surface of the part. A form of wear that is pulled down or the surface of the part is scratched. The so-called corrosive wear refers to the chemical or electrochemical reaction between the surface material and the surrounding medium during the relative sliding process of the friction pair surface, accompanied by mechanical action. Loss phenomenon, corrosion wear is usually a kind of slight wear, but it may also turn into severe wear under certain conditions

In addition, the extensive application of unleaded fuel and the weakening of the lubrication effect on the surface of the valve seat ring have also aggravated the wear of the valve seat ring

With the prolongation of the service life of the engine, the wear of the valve seat becomes more and more serious. The increase of the wear of the valve seat will cause the contact surface of the valve to move, thereby reducing the thickness of the valve head and causing the valve to be prone to elasticity during operation. Deformation, leading to serious accidents such as cylinder air leakage, valve groove or seat ring falling off, resulting in serious problems such as poor reliability and poor stability of the engine system

In addition, because the valve seat ring is inlaid inside the cylinder head and used in conjunction with the cone surface of the valve disc to seal the cylinder and control the intake of fresh air and the discharge of exhaust gas, its poor wear resistance will also directly Affect the fuel consumption and power of the engine

[0004] The valve seat in the prior art, the reason why impact wear, adhesive wear and corrosion wear often occur is inseparable from the material used in the valve seat, especially the structure of the material, the composition of the material, and the preparation of the material. , for example, Chinese patent CN20300898U discloses a valve seat ring, which has a vent hole in the middle of the valve seat ring, and the hole wall surface of the vent hole is coated with a wear-resistant adhesive layer DLC coating. Valve seat rings that are small, not easy to sinter at high temperature and reduce carbon deposits, but the above scheme is to directly coat the surface of the valve seat ring of alloy steel or powder metallurgy material with DLC coating, and there is no transition layer between the DLC coating and the substrate, which is easy to cause Insufficient bonding force between the coating and the substrate, coating peeling and other problems. In addition, in the process of preparing DLC ​​coating film by sputtering, the DLC coating often has problems such as large internal stress and prone to cracks.

[0005] It can be seen that the valve gasket in the prior art has many disadvantages and problems such as poor wear resistance, poor impact resistance, insufficient hardness, poor surface lubrication, and a large surface friction coefficient. The materials used, especially the structure of the material, the components of the material, and the preparation process of the material, all have corresponding technical defects, which further aggravate the problems of multiple impact wear, adhesive wear and corrosion wear. Therefore, it is urgent to provide a kind of Valve seat ring with better wear resistance, better impact resistance, better corrosion resistance and lower surface friction coefficient and its preparation process

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