Method for strengthening surface of runner blade of metal hydraulic turbine through combination of electro-sparking deposition and laser cladding

A technology of electric spark deposition and laser cladding, applied in metal material coating process, coating and other directions, can solve the problems of large equipment investment, insufficient strength, easy fatigue and peeling of coatings, etc., achieve huge economic and social benefits, extend the Long service life and good product quality

Inactive Publication Date: 2014-05-21
NORTH CHINA UNIV OF WATER RESOURCES & ELECTRIC POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The laser surface quenching and hardening layer is thin, the equipment investment is large, and the maintenance cost is high; the surface welding wear-resistant material is high in cost, slow in work efficiency, and there are also problems in surface processing; surface thermal spraying pretreatment generally uses sandblasting, which causes environmental pollution , the coating is difficult to process, the combination between the coating and the substrate is a mechanical combination, the bonding strength between the coating and the substrate is not enough, and the coating is prone to fatigue and peeling off when it is impacted; The hardness and hardness are also very high, but the EDM coating is very thin, and it is not easy to cover the area where the turbine is severely worn; the combination of the epoxy emery coating and the substrate is also a mechanical combination, and it is easy to fall off in the strong cavitation area; polyurethane elastic coating The combination of the layer and the substrate is also a mechanical combination. Although the abrasion resistance of the polyurethane elastic coating is good, its mechanical strength is poor and it is easy to be scratched. Once it is partially scratched, the adjacent area will be torn

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  • Method for strengthening surface of runner blade of metal hydraulic turbine through combination of electro-sparking deposition and laser cladding
  • Method for strengthening surface of runner blade of metal hydraulic turbine through combination of electro-sparking deposition and laser cladding

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Embodiment 1

[0015] The present invention is realized by the following methods in concrete implementation:

[0016] 1. Preparation of iron-nickel alloy powder for laser cladding, the alloy powder is calculated by mass percentage (%): Fe48%, Ni15%, Cr15%, W4.4%, Mo5.6%, B2.6 %, Si5.6%, Co1% and Al2.8%; the electrode material used in EDM is submicron WC-8Co ceramic cemented carbide;

[0017] 2. Under the protection of argon gas, CO2 laser is used to carry out laser cladding treatment on the outer surface of the blade substrate 4-1 of the water turbine runner (the water turbine runner is made of figure 1 It is given that the upper crown 3, the lower ring 1 and the blade 2 between the upper crown and the lower ring are connected together, and 4 in the figure is the cutting part of the blade), and the inner and outer surfaces are clad with iron-nickel alloy powder layers 4-2. The diameter of the laser beam is Φ2-4mm, the laser power is 3-4KW, the scanning speed is 2-5mm / s, and the coaxial blow...

Embodiment 2

[0021] The iron-nickel alloy powder can also be expressed by mass percentage: Fe48.2%, Ni15.2%, Cr14.9%, W4.2%, Mo5.7%, B2.9%, Si5.7% , Co1.1% and Al2.1% composition, its preparation method is the same as embodiment 1.

Embodiment 3

[0023] The iron-nickel alloy powder can also be expressed by mass percentage: Fe48.8%, Ni14.8%, Cr15.1%, W3.8%, Mo5.8%, B2.5%, Si5.9% , Co0.9% and Al2.4% composition, its preparation method is the same as embodiment 1.

[0024] It can be seen from the above that the high temperature of 16000°C in plasma cladding and 24500°C in EDM in the present invention causes metallurgical bonding between the composite coating and the substrate. After testing, the surface hardness of the coating reaches 884.8HV~1293.9HV, and the hardness of the substrate It is 307.1HV, and the hardness can be increased by 3 to 4 times; the wear resistance of the composite coating can be increased by 1 to 3 times than that of the substrate, that is to say, the composite coating formed by EDM combined with laser cladding The layer and the substrate are firmly bonded, and the coatings also show infiltration metallurgical bonding. The thickness of the coating is large, so that the blade has high hardness, good ...

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Abstract

The invention relates to a method for strengthening the surface of a runner blade of a metal hydraulic turbine through combination of electro-sparking deposition and laser cladding. By performing combined treatment of electro-sparking deposition and laser cladding on the runner blade of the metal hydraulic turbine, the problems that the performances including hardness, wear resistance, corrosion resistance and impact resistance of the surface of the runner blade of the hydraulic turbine are low and the service life of a runner of the metal hydraulic turbine is short can be effectively solved. The method comprises the steps of cladding iron-nickel base alloy powder on the surface of the runner blade of the hydraulic turbine by using laser beams to form a hard alloy coating layer; then, performing electro-sparking deposition on a WC (wolfram carbine) ceramic hard alloy on the basis of the laser cladding coating layer to form a composite coating layer with combination of electro-sparking deposition and laser cladding. The method disclosed by the invention is simple, high in production efficiency and good in product quality, and the problem of treating the surface of the blade of the hydraulic turbine is effectively solved, so that the performances including hardness, wear resistance, corrosion resistance and impact resistance of the surface of the runner blade of the hydraulic turbine are improved, the service life of the runner of the metal hydraulic turbine is prolonged, and great economic and social benefits are achieved.

Description

technical field [0001] The invention relates to a hydraulic power generation machine, in particular to a method for enhancing the surface of a runner blade of a metal water turbine by using electric spark deposition combined with laser cladding. Background technique [0002] Water turbine is an important equipment commonly used in hydropower generation. Hydropower generation is one of the important sources of electric energy. In particular, my country is a country rich in hydropower resources in the world. Hydropower has become one of the renewable energy sources that my country focuses on. Hydropower can be developed. The capacity is 380 million kw, and the annual power generation capacity is 1.9 trillion kw.h, which is equivalent to the power generation capacity of 1.1 billion tons of raw coal. One of the characteristics of my country's rivers is the high sediment content. There are 115 rivers with an average annual sediment discharge of more than 10 million tons, and the t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C24/10C23C26/02C22C30/00
Inventor 王建升李勇卢海霞唐明奇冯在强阎镇威张玉新
Owner NORTH CHINA UNIV OF WATER RESOURCES & ELECTRIC POWER
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