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Method for improving valve rod surface wear resistance under high-temperature dry friction conditions

A dry friction and wear resistance technology, applied in the field of improving the wear resistance of the valve stem surface under the condition of high temperature dry friction, can solve the problems of shallow hardened layer, limited range of wear resistance improvement, limited hardness, etc., to achieve enhanced wear resistance. performance, the effect of improving service life

Inactive Publication Date: 2017-10-10
WENZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the hardened layer etched by laser is shallow, the increase in hardness is limited, and the range of increase in wear resistance is limited.
Therefore, in the working environment of high temperature and high pressure dry friction, the single use of laser processing technology cannot meet the requirements

Method used

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  • Method for improving valve rod surface wear resistance under high-temperature dry friction conditions

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (1) Stem surface pretreatment: adopt conventional machining to make the diameter of the valve stem smaller than the design size by 1mm;

[0031] (2) Preparation of laser cladding coating on the surface of the valve stem: a coating with a thickness of 2mm is obtained by laser cladding, specifically:

[0032] a) Degrease and decontaminate the machined surface, clean it with alcohol, and then preheat the valve stem. The preheating temperature is 400°C and the preheating time is 2 hours;

[0033] b) Configure cladding powder, the matrix material is Ni60M alloy powder, and the lubricating phase is CaF 2 Powder, composite powder mass percent: Ni60M alloy powder 85%, CaF 2 Powder 15%, put it into a ball mill and mix evenly, the stirring time is 2 hours;

[0034] c) Multi-channel single-layer cladding is carried out on the surface of the valve stem by fiber laser and coaxial powder feeding; and inert gas is used simultaneously to protect the laser cladding area; the laser cla...

Embodiment 2

[0040] (1) Stem surface pretreatment: adopt conventional machining to make the diameter of the valve stem smaller than the design size by 1mm;

[0041] (2) Preparation of laser cladding coating on the surface of the valve stem: a coating with a thickness of 2mm is obtained by laser cladding, specifically:

[0042] a) Degrease and decontaminate the machined surface, clean it with alcohol, and then preheat the valve stem. The preheating temperature is 400°C and the preheating time is 2 hours;

[0043] b) Configure cladding powder, the matrix material is Ni60M alloy powder, and the lubricating phase is CaF 2 Powder, the mass percentage of composite powder is: Ni60M alloy powder 90%, CaF 2 Powder 10%, put it into a ball mill and mix evenly, the stirring time is 2 hours;

[0044] c) Multi-channel single-layer cladding is carried out on the surface of the valve stem by fiber laser and coaxial powder feeding; and inert gas is used simultaneously to protect the laser cladding area; ...

Embodiment 3

[0050] (1) Stem surface pretreatment: adopt conventional machining to make the diameter of the valve stem smaller than the design size by 1mm;

[0051] (2) Preparation of laser cladding coating on the surface of the valve stem: a coating with a thickness of 2mm is obtained by laser cladding, specifically:

[0052] a) Degrease and decontaminate the machined surface, clean it with alcohol, and then preheat the valve stem. The preheating temperature is 400°C and the preheating time is 2 hours;

[0053] b) Configure cladding powder, the matrix material is Ni60M alloy powder, and the lubricating phase is CaF 2 powder, the mass percentage of composite powder is: Ni60M alloy powder 95%, CaF 2 5% powder, put it into a ball mill and mix evenly, the stirring time is 2 hours;

[0054] c) Multi-channel single-layer cladding is carried out on the surface of the valve stem by fiber laser and coaxial powder feeding; and inert gas is used simultaneously to protect the laser cladding area; t...

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Abstract

The invention relates to a method for improving valve rod surface wear resistance under high-temperature dry friction conditions. The method comprises the following steps: performing pre-treatment on a valve rod surface; performing laser cladding on the pre-treated valve rod surface; then, performing after-treatment on the surface which is subjected to the laser cladding; etching a microgroove in the machined surface by laser; finally, performing microhoning and cleaning treatment on the surface into which the microgroove is etched by the laser, and removing residues from the edges of the microgroove and the exterior of the microgroove. A laser cladding technology and a laser micro-texture technology are effectively combined so as to solve the problem that a valve body of a re-heating double-valve group is easily worn under the high-temperature dry friction conditions. According to a compound process, the valve rod surface has high-temperature self-lubricating property and high hardness, and also has a debris-storage and friction-reducing groove, so that the wear resistance of the valve rod under the high-temperature dry friction conditions is enhanced, and the service life of the valve rod is prolonged.

Description

technical field [0001] The invention relates to a method for improving the wear resistance of the valve stem surface under the condition of high temperature dry friction. Background technique [0002] The reheat double valve group in the nuclear power steam turbine unit can ensure the safe operation of the steam turbine. Its valve stem works in a high temperature and high pressure environment of 400 ° C and 16.7 MPa, and is in a dry friction state. During operation, on the one hand, the valve stem is subjected to steam impact and lateral or longitudinal vibration in the high-temperature and high-pressure flow field; on the other hand, the hardness of the valve stem material decreases and the plasticity increases at high temperature, which makes the valve stem extremely prone to wear. Seriously affect its working performance and service life. Therefore, it is required to have good properties such as high temperature resistance, wear resistance and high temperature self-lubri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C24/10
CPCC23C24/103
Inventor 冯爱新张津超薛伟杨海华赵莹程好陈欢贾天代刘勇
Owner WENZHOU UNIVERSITY