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Cobalt-nickel-free based alloy for strengthening coating of sealing surface of nuclear power valve

A technology of valve sealing and nickel-based alloys, which is applied in the direction of coating and metal material coating technology, can solve the problems of increasing the difficulty and cost of nuclear fuel shielding, the high price of cobalt-based alloys, and the threat of maintenance personnel, so as to improve the comprehensive mechanical properties , small thermal deformation, fast heating and cooling

Inactive Publication Date: 2010-06-02
SUZHOU UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high price of cobalt-based alloys and the lack of cobalt resources in my country, Chinese scientific and technological workers have been looking for substitutes for cobalt-based alloys.
In addition, for valves working in a nuclear environment, cobalt-based alloys present a big defect: Co59 in cobalt-based alloy wear and corrosion fragments will form Co60 isotopes after being excited by neutron irradiation, and Co60 has an extremely long half-life. Strong radioactive sources will increase the maintenance time and threaten the maintenance personnel during shutdown maintenance, and will also greatly increase the difficulty and cost of nuclear fuel shielding

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] (1) The percentage by weight of the cobalt-free nickel-based alloy that prepares the nuclear power valve sealing surface is:

[0041] Chromium (Cr) 37.5-38.5%; Carbon (C) 5.0-6.0%; Silicon (Si) 2.0-2.5%; Boron (B) 1.0-1.5%; 2 o 3 ) 0.5 to 1.5%; the rest is nickel (Ni).

[0042] According to the weight percentage, use a stirring ball mill to mix and prepare the required mixed powder, the powder particle size is 200-300 mesh, and dry in an oven;

[0043] (2) Place the nuclear power valve to be processed on the laser processing machine tool, and guide the laser working head directly above the target area;

[0044] (3) On the sealing surface of the nuclear power valve of the 1Cr18Ni9Ti austenitic stainless steel substrate, a power density of 10 is used 4 W / cm 2 The laser beam irradiates the surface of the substrate to form a molten pool, which is synchronously fed into the prepared alloy powder. The powder carrier gas is nitrogen, and nitrogen is used as a protective ga...

Embodiment 2

[0047] (1) The percentage by weight of the cobalt-free nickel-based alloy that prepares the nuclear power valve sealing surface is:

[0048] Chromium (Cr) 37.5-38.5%; Carbon (C) 5.0-6.0%; Silicon (Si) 2.0-2.5%; Boron (B) 1.0-1.5%; 2 o 3 ) 0.5 to 1.5%; the rest is nickel (Ni).

[0049] According to the percentage by weight, use a stirring ball mill to mix and prepare the required mixed powder. The powder particle size is 200-300 mesh. Use ether to dissolve methyl cellulose as a binder, and blend it with the above powder mixture to form a paste. The nuclear power valve on the stainless steel substrate The sealing surface is pre-coated with a ring-shaped pre-coating with an average diameter of 50mm, a width of 5mm, and a thickness of 2.5mm, and dried in an oven;

[0050] (2) Place the nuclear power valve to be processed on the laser processing machine tool, and guide the laser working head directly above the target area;

[0051] (3) On the nuclear power valve sealing surface ...

Embodiment 3

[0054] The specific steps are the same as in Embodiment 1, the difference is that step (3) laser power density is adjusted to 10 5 W / cm 2 , the laser scanning speed was adjusted to 6mm / s, and a coating with a hardness of HRC45 was obtained.

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PUM

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Abstract

The invention discloses a cobalt-nickel-free based alloy for a strengthening coating of a sealing surface of a nuclear power valve. The alloy contains the following components by weight percentage: 37.5%-38.5% of chromium, 5.0-6.0 % of carbon, 2.0%-2.5% of silicon, 1.0%-1.5% of boron, 0.5%-1.5% of yttrium oxide and the balance of nickel. The mixing alloy powder is compounded, and the strengthening coating is prepared by a laser cladding technology. The obtained cobalt-nickel-free based alloy strengthening coating of the sealing surface of the nuclear power valve has the relative parameters as follows: the average hardness HRC is 45-50, and is 39-43 higher than the traditional cobalt-nickel alloy coating; the grain size is 11-12, and is finer than the traditional plasma spray-welding coating of 9-10 and the flame surfacing welding layer of 8-9, which is favorable for the comprehensive mechanical property correspondingly; the combined bandwidth of the coating and the base body is 25-40 mum, and is compacter than the traditional plasma spray-welding combined band with the width of 80-120 mum and the flame surfacing welding combined band with the width of 20-300 mum. The invention has the advantages of saving of noble metal, i.e. cobalt, cost reduction, simple preparation technology, conformance to special requirement of nuclear environment, and the like.

Description

technical field [0001] The invention relates to a cobalt-free nickel-based alloy, in particular to a cobalt-free nickel-based alloy applied to strengthening coatings on sealing surfaces of nuclear power valves. Background technique [0002] Valves occupy a considerable proportion in mechanical products, especially in nuclear power, thermal power, petrochemical, metallurgy and other industries, valves play a key role and are used in a very large amount. With the advancement of science and technology, in recent years, the valves used in various valve industries at home and abroad are developing in the direction of high parameters, such as large size, high temperature and high pressure resistance, strong corrosion resistance and strong friction, high reliability and long life. [0003] The service conditions of high-parameter valves are quite harsh, and the required safety and reliability are very high. For example, nuclear-grade valves are required to have a comprehensive ser...

Claims

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Application Information

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IPC IPC(8): C22C19/05C23C24/10
Inventor 刘秀波傅戈雁张宗列陆建东石世宏孙承峰刘双魏宏璞
Owner SUZHOU UNIV
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