Powder for surface coating of ball body of cryogenic regulating valve as well as preparation method and application of powder

Abstract

The invention provides powder for a cryogenic regulating valve ball surface coating and a preparation method and application of the powder, and belongs to the technical field of alloy powder and thermal spraying coatings. The powder for the ball surface coating of the cryogenic regulating valve comprises the following components in percentage by mass: 1.5 to 2.5 percent of Al, 2.0 to 3.0 percent of Ti, 2.4 percent of Mo, 4.6 percent of Nb, 17.8 percent of Fe, 19.5 percent of Cr and the balance of Ni. By accurately regulating and controlling the contents of all the elements, the obtained powder material can ensure high hardness and high wear resistance, meanwhile, the bonding strength of a coating is remarkably improved, the service reliability of the cryogenic ball valve body is improved, and the later maintenance cost of parts is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alloy powder and thermal spraying coating technology, in particular to a powder for surface coating of cryogenic regulating valve ball, and a preparation method and application thereof. BACKGROUND

[0002] Reusable space transportation system is the focus of current international space field, and the core is to improve the reuse performance of key components to significantly reduce launch cost, improve mission frequency and reliability. In the engine, the cryogenic regulating valve ball is long-term served in the cryogenic environment of liquid methane / liquid oxygen (-160℃ or below), and at the same time, it is subjected to high pressure working medium scouring, high frequency opening and closing cycle and severe thermal shock. This extreme working condition is easy to cause surface wear failure, low temperature corrosion and fatigue damage of the ball, which seriously restricts the service life of the valve and the reliability of the system.

[0003] Currently, in order to alleviate the equipment stability deterioration and high replacement cost caused by ball valve wear, surface wear-resistant coating technology has become a common solution in the industry. In view of the fact that nickel-based alloy has excellent low-temperature toughness and high hardness characteristics, it is widely used for cryogenic valve strengthening. However, although the traditional nickel-based coating can improve the surface microhardness and wear resistance, it has the inherent defect of insufficient interface bonding strength, which is easy to cause coating peeling under cryogenic alternating load, directly threatening the safe operation of the component.

[0004] Therefore, it is an urgent need to develop a new type of nickel-based alloy coating powder with high surface hardness, excellent wear resistance and strong interface bonding force, which has become an urgent need to break through the technical bottleneck of cryogenic ball valve. SUMMARY

[0005] Therefore, the present application aims to provide a powder for surface coating of cryogenic regulating valve ball, and a preparation method and application thereof.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme: One of the technical schemes of the present application is a powder for surface coating of cryogenic regulating valve ball, which comprises the following components in mass percentage: Al 1.5-2.5%, Ti 2.0-3.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance is Ni.

[0007] In a preferred embodiment of the present application, the powder comprises the following components in mass percentage: Al 2.0-2.5%, Ti 2.5-3.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance is Ni.

[0008] In a preferred embodiment of the present application, the particle size of the powder for surface coating of cryogenic regulating valve ball is 30-60 μm.

[0009] The second technical solution of the present application is a preparation method of the powder for the surface coating of the cryogenic regulating valve ball, comprising the following steps: Step 1, batching, respectively weighing high-purity aluminum blocks, Ni-30Ti, high-purity molybdenum blocks, Ni-60Nb, high-purity iron blocks, Ni-60Cr and high-purity nickel blocks; Step 2, using plasma beam melting technology to prepare pre-alloyed bars from the materials after batching in step 1, and then preparing the pre-alloyed bars into powder.

[0010] In the preferred embodiment of the present application, the content of Al in the high-purity aluminum block is greater than 99.9 wt.%; the content of Ti in the Ni-30Ti is greater than 99.9 wt.%; the content of Mo in the high-purity molybdenum block is greater than 99.9 wt.%; the content of Nb in the Ni-60Nb is greater than 99.9%; the content of Fe in the high-purity iron block is greater than 99.9%; the content of Cr in the Ni-60Cr is greater than 99.9%; and the content of Ni in the high-purity nickel block is greater than 99.9%.

[0011] In the preferred embodiment of the present application, the parameters in the plasma beam melting technology are set as follows: first melting at 1550℃ for 70 min, then melting at 1650℃ for 25 min after increasing the temperature, then melting at 1530℃ for 35 min after decreasing the temperature, then cooling to form an ingot, and finally homogenizing treatment at 1020℃ for 30 min in a vacuum atmosphere.

[0012] In the preferred embodiment of the present application, the diameter of the pre-alloyed bars is 50 mm, and the length is 500 mm.

[0013] In the preferred embodiment of the present application, the method for preparing the pre-alloyed bars into powder is gas atomization.

[0014] The third technical solution of the present application is a method for improving the hardness, wear resistance and bonding strength of the surface coating of a cryogenic regulating valve ball, which uses the powder for the surface coating of the cryogenic regulating valve ball to prepare the coating.

[0015] The present application discloses the following technical effects: The present application can significantly improve the bonding strength of the coating while ensuring high hardness and high wear resistance by precisely controlling the content of each element, thereby improving the reliability of the cryogenic ball valve body in service and reducing the cost of later maintenance of the parts.

[0016] The powder for the surface coating of the cryogenic regulating valve ball provided by the present application is suitable for various spraying processes, including but not limited to the deposition methods such as gas metal arc welding, supersonic flame spraying, atmospheric plasma spraying and cold spraying. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the embodiments will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only merely some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0018] Figure 1 Microhardness of the alloy powder of the present application after high velocity oxygen fuel spraying of Example 1, Example 2 and Example 3; Figure 2 Bonding strength of the alloy powder of the present application after high velocity oxygen fuel spraying of Example 1, Example 2 and Example 3; Figure 3 Volume friction and wear rate of the alloy powder of the present application after high velocity oxygen fuel spraying of Example 1, Example 2 and Example 3. DETAILED DESCRIPTION

[0019] The various illustrative embodiments of the present application will now be described in detail, which should not be considered limiting on the present application, but rather as a description of certain aspects, features, and embodiments of the present application.

[0020] It should be understood that the terms used in the present application merely describe particular embodiments, and are not intended to limit the present application. In addition, for the numerical ranges in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intermediate value in the stated range, is also encompassed within the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference in this specification is not intended as an admission that the reference is prior art, but rather that the reference is part of the technical knowledge in the art.

[0022] Many modifications and variations of this application specification can be made in the light of the above teachings without departing from the spirit or scope of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only. It is intended to cover all alternatives, modifications and equivalents.

[0023] As used herein, "comprise", "comprising", "having", "including", "contain", "containing", "include" and the like are open-ended terms that are intended to mean including but not limited to.

[0024] The technical solutions described in the present application are conventional solutions in the art if not specifically stated, and the reagents or raw materials used are purchased from commercial channels or are publicly known if not specifically stated.

[0025] In the examples, the content of Al in the high-purity aluminum block is greater than 99.9 wt.%; the content of Ti in the Ni-30Ti particles is greater than 99.9 wt.%; the content of Mo in the high-purity molybdenum block is greater than 99.9 wt.%; the content of Nb in the Ni-60Nb particles is greater than 99.9%; the content of Fe in the high-purity iron block is greater than 99.9%; the content of Cr in the Ni-60Cr particles is greater than 99.9%; and the content of Ni in the high-purity nickel block is greater than 99.9%.

[0026] In the examples, the preparation method of the powder for the surface coating of the cryogenic control valve ball is as follows: (1) batching, respectively weighing the high-purity aluminum block, Ni-30Ti particles, high-purity molybdenum block, Ni-60Nb particles, high-purity iron block, Ni-60Cr particles and high-purity nickel block; (2) placing the mixture of the above-mentioned metals in a vacuum plasma beam melting furnace for melting, first melting at 1550℃ for 70 min, then melting at 1650℃ for 25 min after increasing the temperature, and then melting at 1530℃ for 35 min after decreasing the temperature, and then cooling to form an ingot, and finally homogenizing treatment at 1020℃ for 30 min in a vacuum atmosphere; (3) processing the ingot obtained in step (2) into a rod with a diameter of 50 mm and a length of 500 mm by a machine tool; (4) placing the rod obtained in step (3) in the electrode induction melting gas atomization equipment of Germany ALD company, and then preparing the alloy powder for spraying by gas atomization, and then selecting the powder with a particle size in the range of 30-60 μm through a screen.

[0027] In order to better understand the present application, the content of the present application will be further illustrated in combination with examples below, but the content of the present application is not limited to the examples below.

[0028] Example 1 A powder for the surface coating of a cryogenic control valve ball, comprising the following components in mass percentage: Al 1.5%, Ti 2.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance being Ni.

[0029] Effect test: The above powder is dried in a vacuum drying oven at 150℃ for two hours, and then mixed uniformly by a powder mixer to ensure uniform distribution of the powder.

[0030] The SUS 304 substrate is sandblasted with 20-30 mesh white steel to remove surface oil and oxides and increase roughness. The compressed air pressure during sandblasting is 0.5 MPa, the sandblasting distance is 100-120 mm, and the sandblasting angle is 70°-90°.

[0031] The HVOF process parameters are as follows: the relative movement speed of the spray gun is 600 mm / s, the spraying distance is 380 mm, the kerosene flow rate is 5.9 g / h, the back pressure is 113.6 psi, the oxygen flow rate is 2000 SCFH, the back pressure is 139.9 psi, nitrogen is used as the powder carrying gas with a flow rate of 24 SLFH, and the coating thickness is 0.4-0.5 μm.

[0032] The above powder is sprayed by HVOF to obtain a HVOF coating with no obvious defects, the surface microhardness is 559.4 HV 0.1 , and the bonding strength between the coating and the substrate is 67.6 MPa.

[0033] The reciprocating friction and wear test of the coating is carried out by a CFT-1 material surface performance comprehensive analyzer under the conditions of a load of 20 N, a single stroke of 5 mm, a rotation speed of 500 t / min, and an experimental time of 30 min. The results show that the volume wear rate of the coating is 4.11×10 -6 mm³·N -1 ·m -1 .

[0034] Example 2 A powder for a cryogenic regulating valve ball surface coating, comprising the following components in mass percentage: Al 2.0%, Ti 2.5%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance being Ni.

[0035] Effect test: The above powder is dried in a vacuum drying oven at 150℃ for two hours, and then mixed uniformly by a powder mixer to ensure uniform distribution of the powder.

[0036] The SUS 304 substrate is sandblasted with 20-30 mesh white steel to remove surface oil and oxides and increase roughness. The compressed air pressure during sandblasting is 0.5 MPa, the sandblasting distance is 100-120 mm, and the sandblasting angle is 70°-90°.

[0037] The supersonic flame spraying process parameters are as follows: the relative movement speed of the spray gun to the workpiece is 600 mm / s; the spraying distance is 380 mm; the kerosene flow rate is 5.9 g / h, and the back pressure is 113.6 psi; the oxygen flow rate is 2000 SCFH, and the back pressure is 139.9 psi; nitrogen is used as the powder feeding carrier gas, and the flow rate is 24 SLFH; and the coating thickness is 0.4-0.5 μm.

[0038] The above powder is sprayed by supersonic flame spraying to obtain a supersonic flame sprayed coating without obvious defects, and the surface microhardness of the coating is 566.7 HV 0.1 , and the bonding strength between the coating and the substrate is 71.1 MPa.

[0039] The reciprocating friction and wear test of the coating is carried out by using a CFT-1 type material surface performance comprehensive analyzer under the conditions of a load of 20 N, a single stroke of 5 mm, a rotation speed of 500 t / min, and an experimental time of 30 min. The results show that the volume wear rate of the coating is 3.92×10 -6 mm³·N -1 ·m -1 .

[0040] Example 3 A powder for a cryogenic regulating valve ball surface coating, comprising the following components in mass percentage: Al 2.5%, Ti 3.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance being Ni.

[0041] Effect test: The above powder is dried in a vacuum drying oven at 150℃ for two hours, and then uniformly mixed by using a powder mixer to ensure the uniformity of the powder distribution.

[0042] The SUS 304 substrate is sandblasted by using 20-30 mesh white jade steel to remove surface oil stains and oxides and to increase the roughness. The pressure of the compressed air during sandblasting is 0.5 MPa, the sandblasting distance is 100-120 mm, and the sandblasting angle is 70°-90°.

[0043] The supersonic flame spraying process parameters are as follows: the relative movement speed of the spray gun to the workpiece is 600 mm / s; the spraying distance is 380 mm; the kerosene flow rate is 5.9 g / h, and the back pressure is 113.6 psi; the oxygen flow rate is 2000 SCFH, and the back pressure is 139.9 psi; nitrogen is used as the powder feeding carrier gas, and the flow rate is 24 SLFH; and the coating thickness is 0.4-0.5 μm.

[0044] The above powder is sprayed by supersonic flame spraying to obtain a supersonic flame sprayed coating without obvious defects, and the surface microhardness of the coating is 576.8 HV0.1 The bonding strength between the coating and the substrate is 74.9 MPa.

[0045] The reciprocating friction and wear test of the coating is carried out by using a CFT-1 material surface performance comprehensive analyzer under the conditions of a load of 20 N, a single stroke of 5 mm, a rotating speed of 500 t / min, and an experimental time of 30 min. -6 The volume wear rate of the coating is 3.88*10 -1 -1 .

[0046] The above only describes the preferred embodiments of the present application, and it should be noted that the ordinary skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.​

Claims

1. A powder for cryogenic control valve ball surface coating, characterized by, By mass percent, the following components are included: Al 1.5-2.5%, Ti 2.0-3.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance being Ni.

2. The cryogenic control valve ball surface coating powder according to claim 1, wherein, By mass percent, the following components are included: Al 1.5-2.5%, Ti 2.0-3.0%, Mo 2.4%, Nb 4.6, Fe 17.8%, Cr 19.5%, and the balance being Ni.

3. The cryogenic control valve ball surface coating powder of claim 1, wherein, The particle size of the powder for the surface coating of the cryogenic control valve ball is 30-60 microns.

4. A method of producing the powder for cryogenic control valve ball surface coating according to claim 1, characterized by, The method comprises the following steps: Step 1: ingredients are prepared according to claim 1, and high-purity aluminum blocks, Ni-30Ti, high-purity molybdenum blocks, Ni-60Nb, high-purity iron blocks, Ni-60Cr, and high-purity nickel blocks are weighed separately; Step 2: the raw materials after the ingredients in step 1 are prepared into pre-alloyed rods using plasma beam melting technology, and then the pre-alloyed rods are prepared into powder.

5. The preparation method according to claim 4, characterized in that, The content of Al in the high-purity aluminum block is greater than 99.9wt.%; the content of Ti in the Ni-30Ti is greater than 99.9wt.%; the content of Mo in the high-purity molybdenum block is greater than 99.9wt.%; the content of Nb in the Ni-60Nb is greater than 99.9%; the content of Fe in the high-purity iron block is greater than 99.9%; the content of Cr in the Ni-60Cr is greater than 99.9%; and the content of Ni in the high-purity nickel block is greater than 99.9%.

6. A method of improving the hardness, wear resistance and bond strength of a cryogenic regulator valve ball surface coating, characterized by, The coating is prepared using the powder for the surface coating of the cryogenic control valve ball of claim 1.

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