CN111962065A

CN111962065A - Manufacturing method of stainless steel tube fin for nuclear power high-temperature heat dissipation

Info

Publication number: CN111962065A
Application number: CN202010743362.5A
Authority: CN
Inventors: 杜治华; 黎作瑜; 阳义
Original assignee: Chengdu Qingshi Laser Technology Co ltd
Current assignee: Chengdu Qingshi Laser Technology Co ltd
Priority date: 2020-07-29
Filing date: 2020-07-29
Publication date: 2020-11-20

Abstract

The invention discloses a method for manufacturing stainless steel tube fins for nuclear power high-temperature heat dissipation, which comprises the following steps: s1, polishing and cleaning the surface of the stainless steel pipe, and cleaning; s2, putting the cladding powder into a powder feeder; s3, clamping and fixing the stainless steel pipe on a numerical control turntable by using a clamp, and introducing cooling water; s4, generating a corresponding processing program; and S5, the powder feeder conveys the cladding powder to laser cladding equipment, the cladding powder is conveyed out by a powder feeding device on the laser cladding equipment to be converged on the surface of the stainless steel pipe, and meanwhile, the laser cladding equipment irradiates the surface of the stainless steel pipe with laser so that the cladding powder and the stainless steel pipe form metallurgical bonding. The radiating fin manufactured by the method is formed in one step, the surface forming is good, the problems caused by welding joints are avoided, no adhesive powder is generated, the fin is uniformly distributed and thick, the wall thickness of the tube is consistent, and the radiating effect is good; the process and the rejection rate are reduced, the cost is greatly reduced, and the efficiency is high.

Description

Manufacturing method of stainless steel tube fin for nuclear power high-temperature heat dissipation

Technical Field

The invention relates to the field of laser processing, in particular to a method for manufacturing a nuclear power high-temperature heat dissipation stainless steel pipe fin.

Background

At present, domestic and foreign nuclear power is used as clean energy, the development of the nuclear power is faster and faster, and until now, the third generation nuclear power technology is applied, and the fourth generation nuclear power technology is also put into production in intensive research. The heat dissipation finned tube is a core component of a steam-water separation reheater in nuclear power. The manufacturing technology core of the radiating finned tube lies in the radiating fins on the surface of the radiating tube, the radiating fins are metal sheets with strong heat conductivity, which are added on the surface of the heat exchange device needing heat transfer, and the heat exchange efficiency is improved by increasing the heat exchange surface area of the heat exchange device. The rapid development of nuclear power always leaves no efficient and durable radiating finned tube, however, China still relies on import at present, and the manufacturing technology of the radiating finned tube is overcome.

At present, four process methods related to fin production are adopted, namely linear cutting, extrusion forming, powder spreading and 3D printing, and cutting.

The wire cutting method comprises the following steps: under the consideration of the existing process method and cost, fins which are uniformly distributed need to be linearly cut on a stainless steel pipe with large outer diameter at least twice. Then, butt welding of the stainless steel pipes is performed. The method mainly has the following problems that firstly, fins cut by a line are not uniformly distributed and have large thickness difference; secondly, each piece of equipment needs at least 2 weeks for linear cutting, so that the efficiency is low; the length of the wire cutting is limited, and the wire cutting can only be spliced and butt-welded to form enough length after cutting, but no matter what welding method is adopted for butt welding, axial and radial deformation is difficult to control to achieve accurate butt joint, so that the rejection rate is high; quality risks and hidden dangers of the welding joint of the pipe butt welding are not allowed for nuclear parts.

The extrusion forming method comprises the following steps: under the prior art, sectional extrusion molding is needed, and then the extruded fin section is connected with the stainless steel pipe by welding. The extrusion formed fin has good forming effect and uniform distribution. But still has the problems of lower efficiency, quality risk in welding, high rejection rate and the like.

Powder laying 3D printing method: under the condition of the prior art, the printing length is still limited, the printing processing can not be finished at one time, and the stainless steel pipe is always required to be welded and connected to reach the length. Moreover, the printed fins are difficult to ensure that the whole printed piece has no defects such as air holes, slag inclusion, non-fusion, cracks and the like, and the risk of the defects is difficult to evaluate, particularly the welded joints.

The cutting processing method has the following defects: firstly, the thin-wall part is easy to deform in the processing process; secondly, the long and thin finned tube is difficult to process at one time; welding butt joint is needed, welding quality risks exist, and the rejection rate is high and the cost is high.

Based on the defects of the manufacturing methods of the radiating fins, the invention provides a manufacturing method of stainless steel tube fins for nuclear power high-temperature radiation.

Disclosure of Invention

The invention aims to: the method for manufacturing the stainless steel pipe fins for nuclear power high-temperature heat dissipation utilizes the laser cladding principle to print the heat dissipation fins on the thinner stainless steel pipe, and solves the problems of welded joints, unstable quality of the steel pipe, deformation of a pipe body, low production efficiency, high cost, constantly changing technical indexes and requirements and the like.

The technical scheme adopted by the invention is as follows:

a manufacturing method of a stainless steel tube fin for nuclear power high-temperature heat dissipation comprises the following steps:

s1, preparing a stainless steel pipe, polishing and cleaning the surface of the stainless steel pipe, and cleaning;

s2, placing the cladding powder into a powder feeder, and keeping the temperature at 70-80 ℃ for 7-10 h;

s3, clamping and fixing the stainless steel pipe on a numerical control turntable by using a clamp, and introducing cooling water into the stainless steel pipe;

s4, drawing a fin shape on computer software, scanning to generate a cladding processing track, uploading the cladding processing track to laser cladding equipment, and generating a corresponding processing program;

s5, the powder feeder conveys the cladding powder to laser cladding equipment, the powder feeder on the laser cladding equipment sends the cladding powder to the surface of the stainless steel pipe for convergence, and meanwhile, the laser cladding equipment performs laser irradiation on the surface of the stainless steel pipe to enable the cladding powder and the stainless steel pipe to form metallurgical bonding;

and S6, detecting the size of the fin by using a measuring tool, and then carrying out flaw detection on the fin.

The laser cladding device comprises a powder feeder, a numerical control rotary table, a computer, laser cladding equipment, a rotary table controller and a laser, and further comprises an automatic laser cladding system, wherein the automatic laser cladding system comprises the powder feeder, the numerical control rotary table, the computer and the laser cladding equipment; the laser powder feeding device comprises a laser head, a power supply, a computer, a power feeding device, a rotary table controller, a laser cladding device, a laser, a numerical control rotary table, a laser head and a laser head, wherein the computer processes cladding data and graphs and is connected with the power feeding device, the rotary table controller, the laser cladding device and the laser, the control command is output to the power feeding device, the laser cladding device, the rotary table controller and the laser to work in a cooperative mode, the rotary table controller is connected with the numerical control rotary table, the laser is.

Further, the powder feeding device is a nozzle.

Further, the robot is a 6-axis robot.

Further, the cladding powder is dissimilar metal powder with heat conduction performance.

Further, the cladding powder is pure nickel powder.

Further, in the step S2, the welding powder is kept at the temperature of 70-80 ℃ for 8 h.

Further, the measuring tool in step S6 is a vernier caliper or a measuring tape.

Further, the step S6 of performing flaw detection on the fin specifically includes:

s61, uniformly spraying penetrant inspection liquid on the surface of the fin, and cleaning and removing the penetrant inspection liquid on the surface of the fin by using a cleaning agent after 10-20 minutes;

and S62, after the cleaning agent is volatilized, uniformly spraying a developer on the fin, and observing whether the fin has a crack defect.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the invention relates to a method for manufacturing stainless steel tube fins for nuclear power high-temperature heat dissipation, which is characterized in that a clamp is used for clamping and fixing a stainless steel tube on a numerical control rotary table, cooling water is introduced in the cladding process to cool the stainless steel tube, the stainless steel tube is prevented from being heated and deformed in the cladding process, the angle precision in the cladding process is ensured, the quality of the stainless steel tube fins is further controlled, and the stability is kept.

2. The invention relates to a method for manufacturing stainless steel tube fins for nuclear power high-temperature heat dissipation, which is characterized in that the stainless steel tube fins are formed at one step by a laser automatic cladding system, the surface forming is good, the problems caused by welding joints are avoided, and no adhesive powder is generated; the working procedures and the rejection rate are reduced, and the cost is greatly reduced; compared with other manufacturing methods, the fin manufacturing method has high efficiency.

3. The invention relates to a method for manufacturing stainless steel tube fins for nuclear power high-temperature heat dissipation, which has the advantages that the fins are uniformly distributed and are uniform in thickness, the wall thickness of the tube is consistent, the surface of a cladding layer has certain roughness, processing is not needed, and the heat dissipation surface area is better increased.

4. The invention relates to a method for manufacturing stainless steel tube fins for nuclear power high-temperature heat dissipation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments are briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts, and the proportional relationship of each component in the drawings in the present specification does not represent the proportional relationship in the actual material selection design, and is only a schematic diagram of the structure or the position, in which:

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is a schematic structural diagram of an automatic laser cladding system according to the present invention;

FIG. 3 is a pictorial view of 2 fins formed by cladding according to the present invention;

FIG. 4 is a pictorial view of 20 fins formed by cladding using the present invention;

FIG. 5 is a 50X metallographic image of a material object formed using the present invention;

FIG. 6 is a 100X metallographic image of a material object formed using the present invention;

FIG. 7 is a 200X metallographic image of a material object formed using the present invention.

The reference numbers illustrate: 1-powder feeder, 2-robot, 3-numerical control turntable, 4-turntable controller, 5-laser, 6-computer and 7-laser head.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

The term "connected" in the present invention is not particularly limited, and may be any conventional connection means such as integral molding, welding, riveting, etc., and the specific connection means may be suitably selected according to the conventional technical knowledge in the art. All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

The present invention will be described in detail with reference to the accompanying drawings.

Example 1

As shown in fig. 1, a method for manufacturing a stainless steel tube fin for high-temperature heat dissipation of nuclear power includes the following steps:

s1, preparing a stainless steel pipe, polishing and cleaning the surface of the stainless steel pipe, and cleaning; polishing the surface of the stainless steel pipe, removing an oxide layer on the surface of the stainless steel pipe, and cleaning oil stains on the surface of the stainless steel pipe to keep the stainless steel pipe clean;

s2, placing the cladding powder into a powder feeder, and keeping the temperature at 75 ℃ for 8 h;

s3, clamping and fixing the stainless steel pipe on a numerical control turntable by using a clamp, and introducing cooling water into the stainless steel pipe; and cooling water is introduced in the cladding process to cool the stainless steel pipe, so that the stainless steel pipe is prevented from being heated and deformed in the cladding process, the angle precision in cladding is ensured, the quality of the stainless steel pipe fins is further controlled, and the stability is kept.

Further, the automatic laser cladding system is further included, as shown in fig. 2, the automatic laser cladding system includes the powder feeder 1, the numerical control turntable 3, the computer 6, the laser cladding device, the turntable controller 4 and the laser 5, and the laser cladding device includes a robot 2, a laser head 7 and a powder feeding device; the laser powder feeding device comprises a power feeder 1, a rotary table controller 4, laser cladding equipment and a laser 5, wherein the power feeder 1, the rotary table controller 4, the laser cladding equipment and the laser 5 are connected through a computer, a control command is output to the power feeder 1, the laser cladding equipment, the rotary table controller 4 and the laser 5 to work cooperatively, the rotary table controller 4 is connected with a numerical control rotary table 3, the laser 5 is connected with a laser head 7 through an optical fiber to provide laser, and the power feeder 1 is connected with a power feeding device through a gas path.

Further, the powder feeding device is a nozzle.

Further, the robot 2 is a 6-axis robot.

Further, the cladding powder is pure nickel powder.

In the laser automatic cladding system of the invention, a powder feeder 1 is a cladding powder supply element, dries and heats powder to 70-80 ℃, transmits cladding powder to a nozzle of a laser head 7 through a gas path, and finally focuses on the surface of a stainless steel pipe through the nozzle; the robot 2 is a moving element of the laser automatic cladding system, and receives a command transmitted from the computer 6 and moves along a predetermined path; the laser 5 provides laser for the laser automatic cladding system, transmits the laser to the laser head 7 through optical fiber and focuses on the surface of the stainless steel pipe; the computer 6 is a data and graphic processing element, and is used for integrating and processing various cladding data of the fins, transmitting the data to the turntable controller 4 to control the numerical control turntable 3, and automatically completing the cladding of the radiating fins by matching with other elements; the laser head 7 is composed of a series of optical elements, the end of which is connected with a nozzle and is the most central part in the laser automatic cladding system. In step S5, the powder feeder 1 delivers the cladding powder to the nozzle of the laser head 7, and delivers the cladding powder to the surface of the stainless steel tube through the nozzle for convergence, and at the same time, the laser 5 enables the laser to deliver the laser to the laser head 7 through the optical fiber and focus on the surface of the stainless steel tube, the laser and the cladding powder are both focused on the surface of the stainless steel tube through the laser head 7 to form a molten pool, and the laser head 7 performs cladding on the surface of the stainless steel tube along a certain path along with the movement of the robot 6, and the molten pool cools and solidifies on the surface of the stainless steel tube along with the movement of the laser, so that the cladding powder and the stainless steel tube form metallurgical bonding, i.

The comparison of the technical effects of the manufacturing method of the present invention with the other four different manufacturing methods is shown in table 1:

table 1: comparison table of technical effects generated by 5 different manufacturing methods

As can be seen from Table 1, laser cladding has obvious advantages in various indexes. Most importantly, butt welding is not needed, the welding defects are in danger no matter what welding is adopted, the inner wall forming is difficult to control, and the like, which are not allowed for nuclear industry parts. And the laser cladding is superior to other manufacturing methods in the problems of cost control, deformation, production efficiency, rejection rate, fin thickness, symmetry and the like. Fig. 5-7 are gold phase diagrams of objects formed using the manufacturing method of the present invention.

By adopting the manufacturing method and the laser automatic cladding system, the stainless steel tube radiating fin is formed at one step, the surface is well formed, no adhesive powder exists, and the problems caused by welding joints are avoided; the working procedures and the rejection rate are reduced, and the cost is greatly reduced; compared with other production methods, the efficiency of manufacturing the fins is obviously improved; the laser cladding heat input is small, and the integral deformation is controlled in a controllable range through a special water cooling device and a clamp; the fins are distributed uniformly with the thickness, and the tube wall thickness is consistent. The cladding layer surface has certain roughness, does not need processing, has better increase radiating surface area. The cladding powder is made of dissimilar metal powder, particularly, a material with good heat conductivity can be selected to further improve the heat dissipation performance of the fin, pure nickel powder is selected preferably, the heat conductivity coefficient is high and reaches 91, the laser cladding forming effect is good, and the process is simple. The invention can easily meet the change of the technical indexes of the fins, such as the thickness, the number, the density, the length and the like of the fins without changing tools, equipment and the like.

Example 2

This example is an example of the stainless steel pipe in example 1.

The stainless steel pipe is 304 stainless steel material, the material components are shown in table 2, the invention prints radiating fins on the thinner stainless steel pipe by utilizing the laser cladding principle, and solves the problems of unstable quality of welded joints and steel pipes, deformation of pipe bodies, low production efficiency, high cost, constantly changing technical indexes and requirements and the like.

Chromium (Cr)	Silicon (Si)	Nickel (Ni)	Manganese (Mn)	Iron (Fe)	Others
						18.0～20.0	2.0～3.0	8.25～10.5	0～2.0	64.5～71.75	Sulfur (S), carbon (C), phosphorus (P)

Table 2: 304 stainless steel material composition

In this embodiment, 20 uniformly distributed fins with a length of 1000mm or more, a width of 0.7mm and a height of 7mm are manufactured on a stainless steel thin-walled tube with a length of 2000mm, a thickness of 1.5mm and a diameter of 20mm by a laser powder feeding cladding method, as shown in fig. 4, and fig. 3 is a real object diagram of cladding 2 fins. In the use process of the stainless steel pipe in the embodiment, the inner cavity of the pipe bears the pressure of more than 10 MPa.

Example 3

This embodiment is to further explain the laser cladding parameters of step S5 in embodiment 1.

In the laser cladding method, main process parameters comprise laser power, scanning speed of a laser head, defocusing amount of laser and powder feeding rate of a powder feeder. The process parameters are shown in table 3:

table 3: laser cladding process parameters

Example 4

This example is a detailed description of another operation of example 1.

s2, placing the cladding powder into a powder feeder, and keeping the temperature at 70 ℃ for 10 hours;

Example 5

This example is a detailed description of another operation of example 1.

s2, placing the cladding powder into a powder feeder, and keeping the temperature at 80 ℃ for 7 h;

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be made by those skilled in the art without inventive work within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.

Claims

1. A manufacturing method of a stainless steel tube fin for nuclear power high-temperature heat dissipation is characterized by comprising the following steps:

2. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 1, wherein: the automatic laser cladding system comprises the powder feeder, the numerical control rotary table, the computer and the automatic laser cladding equipment as claimed in claim 1, and further comprises a rotary table controller and a laser, wherein the automatic laser cladding equipment comprises a robot, a laser head and a powder feeding device; the laser powder feeding device comprises a laser head, a power supply, a computer, a power feeding device, a rotary table controller, a laser cladding device, a laser, a numerical control rotary table, a laser head and a laser head, wherein the computer processes cladding data and graphs and is connected with the power feeding device, the rotary table controller, the laser cladding device and the laser, the control command is output to the power feeding device, the laser cladding device, the rotary table controller and the laser to work in a cooperative mode, the rotary table controller is connected with the numerical control rotary table, the laser is.

3. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 2, wherein: the powder feeding device is a nozzle.

4. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 2, wherein: the robot is a 6-axis robot.

5. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 1, wherein: the cladding powder is dissimilar metal powder with heat conduction performance.

6. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 5, wherein the manufacturing method comprises the following steps: the cladding powder is pure nickel powder.

7. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 1, wherein: in the step S2, the welding powder is kept warm for 8 hours at the temperature of 70-80 ℃.

8. The manufacturing method of the stainless steel tube fin for high-temperature heat dissipation of nuclear power as claimed in claim 1, wherein: the measuring tool in the step S6 is a vernier caliper or a measuring tape.

9. The manufacturing method of the stainless steel tube fin for nuclear power high-temperature heat dissipation according to any one of claims 1 to 8, wherein the manufacturing method comprises the following steps: the specific steps of flaw detection of the fin in the step S6 are as follows: