阅读说明：本技术 一种激光熔化沉积制造翅片热管管壳的方法 (Method for manufacturing finned heat pipe shell by laser melting deposition ) 是由 王秋林 李明富 门正兴 陈诚 阳义 黎作瑜 于 2020-11-20 设计创作，主要内容包括：本发明公开了一种激光熔化沉积制造翅片热管管壳的方法,S1、将不锈钢热管清洗、干燥,并将不锈钢粉末放置于干燥箱中加热；S2、采用Solid Works软件构建翅片的几何模型；S3、将不锈钢热管固定在位于坐标系中的夹具上；S4、采用高能量激光作为能量源,在不锈钢热管冷凝段采用同轴送粉的方法,将不锈钢粉末熔化、快速凝固、逐层沉积,形成一个翅片；S5、旋转不锈钢热管,并返回S4,直至完成所有翅片的制造；S6、采用机加工铣削翅片表面并抛光,得到翅片热管管壳。本发明尺寸精度高,无裂纹与变形；翅片晶粒细小,组织均匀,与基材结合良好,硬度均匀；散热效率高,工艺稳定性好,加工周期短,成本较低。(The invention discloses a method for manufacturing a finned heat pipe shell by laser melting deposition, which comprises the following steps of S1, cleaning and drying a stainless steel heat pipe, and placing stainless steel powder in a drying box for heating; s2, constructing a geometric model of the fin by using Solid Works software; s3, fixing the stainless steel heat pipe on a clamp in a coordinate system; s4, melting and rapidly solidifying stainless steel powder and depositing layer by layer to form a fin by adopting high-energy laser as an energy source and adopting a coaxial powder feeding method at a condensation section of a stainless steel heat pipe; s5, rotating the stainless steel heat pipe, and returning to S4 until all fins are manufactured; and S6, milling the surface of the fin by adopting machining and polishing to obtain the finned heat pipe shell. The invention has high dimensional accuracy and no crack and deformation; the fin has fine grains, uniform tissue, good combination with the base material and uniform hardness; high heat dissipation efficiency, good process stability, short processing period and low cost.)

1. A method of manufacturing a finned heat pipe shell by laser melting deposition, comprising:

s1, cleaning and drying the stainless steel heat pipe, and placing the stainless steel powder in a drying box for heating;

s2, constructing a geometric model of the fin by using Solid Works software;

s3, fixing the stainless steel heat pipe on a clamp in a coordinate system;

s4, melting and rapidly solidifying stainless steel powder and depositing layer by layer to form a fin by adopting high-energy laser as an energy source and adopting a coaxial powder feeding method at a condensation section of a stainless steel heat pipe;

s5, rotating the stainless steel heat pipe, and returning to S4 until all fins are manufactured;

and S6, milling the surface of the fin by adopting machining and polishing to obtain the finned heat pipe shell.

2. The method of laser fuse deposition manufacturing a finned heat pipe shell as claimed in claim 1, wherein: cleaning and drying the stainless steel heat pipe in the step S1, and placing the stainless steel powder in a drying box for heating; the method comprises the following steps:

s1.1, placing a stainless steel heat pipe in alcohol, cleaning for 2-30 min by adopting ultrasonic waves, and drying by adopting an electric hair drier;

s1.2, placing stainless steel powder with the particle size of 10-150 mu m in a drying oven for heating and drying, wherein the heating temperature is 50-100 ℃, and the time is 2-8 hours.

3. The method of laser fuse deposition manufacturing a finned heat pipe shell as claimed in claim 1, wherein: the shape of the fins in the S2 is radial straight fins, circular arc transition is adopted between the fins and the stainless steel heat pipe, the number of the fins is 1-99, the length of the fins is 10-800 mm, and the thickness of the fins is 0.5-5 mm.

4. The method of laser fuse deposition manufacturing a finned heat pipe shell as claimed in claim 1, wherein: the power of the laser in the S4 is 1000-100W, the laser power decreases progressively in the equal difference of the front 3-10 layers, the laser power of the later layer is kept unchanged, and the height of each layer is 0.1-0.5 mm.

5. The method of laser fuse deposition manufacturing a finned heat pipe shell as claimed in claim 4, wherein: the laser has the advantages that the diameter of a light spot is 0.5-1.5 mm, the defocusing amount is 0.1-1.0 mm, the scanning speed is 5-40 mm/s, the protective air flow is 5-30L/min, the powder feeding air flow is 5-30L/min, and the powder feeding amount is 5-30 g/min.

6. The method of laser fuse deposition manufacturing a finned heat pipe shell as claimed in claim 4, wherein: the powder feeding gas and the protective gas are Ar gas with the purity of more than 99.9 percent.

Technical Field

The invention belongs to the technical field of additive manufacturing, and particularly relates to a method for manufacturing a finned heat pipe shell by laser melting deposition.

Background

The effective control of the nuclear power passive heat dissipation system is one of important measures for reducing safety accidents in the nuclear power field. The heat pipe transfers heat by means of phase change of working media in the pipe, and a large amount of heat can be led out without additional power supply, so that a great deal of attention and application are paid to the field of nuclear power temperature control. The condensation section of the heat pipe is a core component for heat output, and the efficiency of the heat pipe can be improved by quickly radiating heat. The fins are manufactured on the heat pipe shell, so that the heat dissipation area can be increased, and the heat dissipation speed is accelerated. The stainless steel has high strength, oxidation resistance, corrosion resistance and high temperature resistance, is suitable for severe environments with strong nuclear power radiation, high temperature and high pressure and strong corrosivity, and is an ideal heat pipe shell material.

At present, the technology for manufacturing fins on stainless steel pipes mainly has 2 ways:

1. machining

And (3) manufacturing the fins meeting the requirements on the shell of the condensation section by turning, milling, linear cutting and the like the stainless steel tube with the thick wall. The process has long period, high processing difficulty and high material waste.

2. Welding of

And fixing the fins on the heat pipe in a welding mode. The heat stress generated by the process to the heat pipe is too large, and the heat pipe and the fins are easy to deform.

Disclosure of Invention

The present invention is directed to a method for manufacturing a finned heat pipe casing by laser melting deposition, so as to solve the problems of conventional machining and welding.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method of laser fused deposition manufacturing a finned heat pipe shell comprising:

s1, cleaning and drying the stainless steel heat pipe, and placing the stainless steel powder in a drying box for heating;

s2, constructing a geometric model of the fin by using Solid Works software;

s3, fixing the stainless steel heat pipe on a clamp in a coordinate system;

s4, melting and rapidly solidifying stainless steel powder and depositing layer by layer to form a fin by adopting high-energy laser as an energy source and adopting a coaxial powder feeding method at a condensation section of a stainless steel heat pipe;

s5, rotating the stainless steel heat pipe, and returning to S4 until all fins are manufactured;

and S6, milling the surface of the fin by adopting machining and polishing to obtain the finned heat pipe shell.

Preferably, the stainless steel heat pipe is cleaned and dried in S1, and the stainless steel powder is placed in a drying oven for heating; the method comprises the following steps:

s1.1, placing a stainless steel heat pipe in alcohol, cleaning for 2-30 min by adopting ultrasonic waves, and drying by adopting an electric hair drier;

s1.2, placing stainless steel powder with the particle size of 10-150 mu m in a drying oven for heating and drying, wherein the heating temperature is 50-100 ℃, and the time is 2-8 hours.

Preferably, the shape of the fins in the S2 is radial straight fins, circular arc transition is adopted between the fins and the stainless steel heat pipe, the number of the fins is 1-99, the length of the fins is 10-800 mm, and the thickness of the fins is 0.5-5 mm.

Preferably, the power of the laser in S4 is 1000-100W, the laser power decreases progressively in the first 3-10 layers, the laser power remains unchanged in the later layers, and the height of each layer is 0.1-0.5 mm.

Preferably, the diameter of a light spot of the laser is 0.5-1.5 mm, the defocusing amount is 0.1-1.0 mm, the scanning speed is 5-40 mm/s, the protective air flow is 5-30L/min, the powder feeding air flow is 5-30L/min, and the powder feeding amount is 5-30 g/min.

Preferably, the powder feeding gas and the protective gas are Ar gas with the purity of more than 99.9 percent.

The method for manufacturing the finned heat pipe shell by laser melting deposition has the following beneficial effects:

according to the invention, the fins of the high-performance heat pipe shell with the rapid solidification structure characteristic are directly prepared and formed through laser melting-rapid solidification layer-by-layer deposition of the metal material, compared with the traditional manufacturing method, the fin of the high-performance heat pipe shell has high dimensional accuracy and is free of cracks and deformation; the fin has fine grains, uniform tissue, good combination with the base material and uniform hardness; high heat dissipation efficiency, good process stability, short processing period and low cost.

Besides, the fin has good perpendicularity with the tangent of the tube, is uniformly distributed on the excircle of the stainless steel tube, has uniform thickness and good straightness, and does not have cracks or other defects; the circular arc transition is realized at the joint of the fin and the tube, the precision is higher, and the stainless steel tube has no deformation.

The fin has fine grains, uniform structure and no defects of microcracks, holes and the like. The combination of the fins and the base material is good; the consistency of the hardness of the same position of the fin is good, and the process stability is good; meanwhile, the heat dissipation efficiency of the fin heat pipe is improved.

Drawings

FIG. 1 is a schematic diagram of the cross-sectional shape and size of a finned heat pipe shell in accordance with embodiment 2 of the present invention.

Fig. 2 is a microstructure of a finned heat pipe shell fabricated in example 2 of the present invention.

FIG. 3 is an X-ray diffractometer (XRD) analysis pattern of the fin manufactured in example 2 of the present invention.

FIG. 4 energy spectrum (EDS) analysis of the junction of a fin and a heat pipe manufactured in example 2 of the present invention.

Fig. 5 shows the time (low temperature heat dissipation) that the finned heat pipe manufactured in example 2 of the present invention takes to cool from 85 c to 45 c.

FIG. 6 shows the behavior of a finned heat pipe manufactured in example 2 of the present invention with respect to the temperature from 650 ℃ to 250 ℃ over time (high-temperature heat dissipation).

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

According to the embodiment 1 of the application, the method for manufacturing the finned heat pipe shell by laser melting deposition comprises the following steps:

s1, cleaning and drying the stainless steel heat pipe, and placing the stainless steel powder in a drying box for heating, wherein the method specifically comprises the following steps:

s1.1, ultrasonically cleaning a stainless steel tube in alcohol for 2-30 min, and drying;

s1.2, the granularity of stainless steel powder is 10-150 mu m, and the powder is placed in a drying box and heated and dried at the temperature of 50-100 ℃ for 2-8 hours.

S2, constructing a geometric model of the fin by using Solid Works software; and constructing a geometric model of the fin on a computer by using Solid Works, Pro/E, UG, Inventor, Rhino and other software.

The fins are radial straight fins, arc transition is adopted between the fins and the heat pipe, the number of the heat pipe fins is 1-99, the length of the fins is 10-800 mm, and the thickness of the fins is 0.5-5 mm.

And S3, fixing the stainless steel heat pipe on a clamp in a coordinate system, namely fixing the processed stainless steel heat pipe in the equipment coordinate system by using a special clamp.

S4, adopting high-energy laser as an energy source, adopting a coaxial powder feeding method at a condensation section of a stainless steel heat pipe, melting stainless steel powder, quickly solidifying and depositing layer by layer to form a fin, wherein the fin specifically comprises the following steps:

the high-energy laser is used as an energy source, and the treated stainless steel powder is melted, rapidly solidified and deposited layer by layer in a coaxial powder feeding mode at the condensation section of the stainless steel heat pipe.

The technological parameters are as follows:

the diameter of a light spot is 0.5-1.5 mm, the defocusing amount is 0.1-1.0 mm, the scanning speed is 5-40 mm/s, the shielding gas flow is 5-30L/min, the powder feeding amount is 5-30 g/min, and Ar gas (the purity is more than 99.9%) is adopted for the powder feeding gas and the shielding gas.

In order to ensure that the fins and the heat pipe are in arc transition, the power is selected to be 1000-100W, the equal difference of the first 3-10 layers is gradually reduced, the power is kept unchanged, and the height of each layer is 0.1-0.5 mm.

S5, rotating the stainless steel heat pipe, and returning to S4 until all fins are manufactured; after finishing the manufacture of one fin, the stainless steel heat pipe is turned by a certain angle (the angle is related to the number and distribution of the fins), and the fin deposition operation is repeated until all the fins are manufactured.

And S6, milling the surface of the fin by adopting machining and polishing to obtain the finned heat pipe shell.

According to embodiment 2 of the present application, referring to fig. 1, the method for manufacturing a finned heat pipe shell by laser melting deposition of the present solution includes:

a1, ultrasonically cleaning a 316 stainless steel tube in alcohol for 10min, and drying; the 316 stainless steel powder with the granularity of 20-53 mu m is placed in a drying oven at the temperature of 80 ℃ for 8 hours.

A2, adopting Solid Works software to construct a geometric model of fins on a computer, wherein the fins are radial straight fins, the fins and the heat pipes are in arc transition, the number of the heat pipe fins is 20, the length of the fins is 200mm, the thickness of the fins is 1mm, and the height of the fins is 3 mm.

A3, fixing the treated 316 stainless steel heat pipe in the equipment coordinate system by a special clamp.

A4, adopting high-energy laser as an energy source, and adopting a coaxial powder feeding mode at a condensation section of the stainless steel heat pipe to melt, quickly solidify and deposit the processed 316 stainless steel powder layer by layer.

In order to ensure that arc transition is formed between the fins and the heat pipe, the power is selected to be 600-450W, the equal difference of the front 5 layers is gradually reduced, the power is kept unchanged, the height of each layer is 0.32mm, the diameter of a light spot is 1.1mm, the defocusing amount is 0.5mm, the scanning speed is 20mm/s, the shielding gas flow is 15L/min, the powder feeding gas flow is 10L/min, the powder feeding amount is 12g/min, and Ar gas is adopted for the powder feeding gas and the shielding gas (the purity is more than 99.9%).

And A5, after manufacturing of one fin, rotating the stainless steel heat pipe by an angle of 18 degrees, and repeating the A4 fin deposition operation until all fins are manufactured.

And A6, milling the surface of the fin by a machining method, and polishing to obtain the fin heat pipe shell meeting the requirements.

The fins manufactured by the laser melting deposition technology have good verticality with the tangent of the tube, are uniformly distributed on the excircle of the stainless steel tube, have uniform thickness and good straightness, and have no obvious defects such as cracks; the circular arc transition is realized at the joint of the fin and the tube, and the precision is higher; the stainless steel pipe has no deformation.

Referring to fig. 2, the fin has fine grains, uniform structure, and no defects such as micro-cracks and holes.

Referring to FIG. 3, the phase of the fin is composed of (Ni-Cr-Fe), (Fe, Ni), CrFe_2.32MoNi、Cr₃Ni5Si₂Composition, the main phase of 316 stainless steel.

Referring to fig. 4, the elemental content of the fin and the base material are maintained at the same level, and 2 bonds well, reaching the level of metallurgical bonding.

The microhardness distribution test of the fin heat pipe shows that the test position is the top of the fin, the uniformity of hardness is better, and the stability of the process is good. Average hardness of fins (280.92 HV)_0.5) Average hardness of the stainless steel tube (209.9 HV)_0.5) The height is 33.8%.

Referring to fig. 5, compared with the stainless steel heat pipe shell with the same specification, the diameter of phi 20mm, the inner diameter of phi 16mm and the length of 280mm, the low-temperature heat dissipation efficiency of the finned heat pipe shell is improved by 16.7%.

Referring to fig. 6, compared with the stainless steel heat pipe shell with the same specification, the diameter of phi 20mm, the inner diameter of phi 16mm and the length of 280mm, the high-temperature heat dissipation efficiency of the finned heat pipe shell of the invention is improved by 33.5%.

According to embodiment 3 of the application, the method for manufacturing the finned heat pipe shell by laser melting deposition comprises the following steps:

b1, ultrasonically cleaning the 316 stainless steel tube in alcohol for 5min, and drying; the 316 stainless steel powder with the granularity of 20-53 mu m is placed in a drying oven at the temperature of 80 ℃ for 8 hours.

B2, adopting Solid Works software to construct a geometric model of fins on a computer, wherein the fins are radial straight fins, the number of the heat pipe fins is 30, the length of the fins is 200mm, the thickness of the fins is 1mm, and the height of the fins is 3 mm.

And B3, fixing the treated 316 stainless steel heat pipe in an equipment coordinate system by using a special clamp.

And B4, melting and rapidly solidifying the processed 316 stainless steel powder in a coaxial powder feeding mode at a stainless steel heat pipe condensation section by using high-energy laser as an energy source, and depositing layer by layer.

The power is selected to be 600W, the height of each layer is 0.32mm, the diameter of a light spot is 1.1mm, the defocusing amount is 0.5mm, the scanning speed is 20mm/s, the protective gas flow is 15L/min, the powder feeding gas flow is 10L/min, the powder feeding amount is 12g/min, and Ar gas (the purity is more than 99.9%) is adopted for the powder feeding gas and the protective gas.

B5, after finishing the manufacture of one fin, turning the stainless steel heat pipe by an angle of 12 degrees, and repeating the B4 fin deposition operation until all the fins are manufactured.

B6, milling the surface of the fin by a machining method, and polishing to obtain the fin heat pipe shell meeting the requirements.

According to embodiment 4 of the application, the method for manufacturing the finned heat pipe shell by laser melting deposition comprises the following steps:

c1, ultrasonically cleaning the 304 stainless steel tube in alcohol for 15min, and drying; the 316 stainless steel powder with the granularity of 20-53 mu m is placed in a drying oven at the temperature of 60 ℃ for 8 hours.

C2, constructing a geometric model of the fins on a computer by using Solid Works software, wherein the fins of the embodiment are radial straight fins, the fins and the heat pipes are in arc transition, the number of the heat pipe fins is 20, the length of the fins is 200mm, the thickness of the fins is 1mm, and the height of the fins is 3 mm.

And C3, fixing the processed 304 stainless steel heat pipe in the equipment coordinate system by using a special clamp.

And C4, melting and rapidly solidifying the treated 316 stainless steel powder in a coaxial powder feeding mode at a stainless steel heat pipe condensation section by using high-energy laser as an energy source, and depositing layer by layer.

In order to ensure that arc transition is formed between the fins and the heat pipe, the power is selected to be 700-550W, the equal difference of the front 5 layers is gradually reduced, the power is kept unchanged, the height of each layer is 0.3mm, the diameter of a light spot is 1.0mm, the defocusing amount is 0.5mm, the scanning speed is 30mm/s, the shielding gas flow is 20L/min, the powder feeding gas flow is 12L/min, the powder feeding amount is 15g/min, and Ar gas is adopted for the powder feeding gas and the shielding gas (the purity is more than 99.9%).

C5, after finishing the manufacture of one fin, turning the stainless steel heat pipe by an angle of 18 degrees, and repeating the deposition operation of the C4 fin until all the fins are manufactured.

C6, milling the surface of the fin by a machining method, and polishing to obtain the finned heat pipe shell.

According to the embodiment 5 of the application, the method for manufacturing the finned heat pipe shell by laser melting deposition comprises the following steps:

d1, ultrasonically cleaning the 304 stainless steel tube in alcohol for 20min, and drying; the particle size of 304 stainless steel powder is 20-53 mu m, and the powder is placed in a drying oven at the temperature of 80 ℃ for 6 hours.

D2, constructing a geometric model of the fins on a computer by using Solid Works software, wherein the fins are radial straight fins, the fins and the heat pipes are in arc transition, the number of the heat pipe fins is 20, the length of the fins is 100mm, the thickness of the fins is 1mm, and the height of the fins is 3 mm.

D3, fixing the processed 304 stainless steel heat pipe in the equipment coordinate system by using a special clamp.

D4, adopting high-energy laser as an energy source, and adopting a coaxial powder feeding mode at a condensation section of the stainless steel heat pipe to melt, quickly solidify and deposit the processed 304 stainless steel powder layer by layer.

In order to ensure that arc transition is formed between the fins and the heat pipe, the power is selected to be 550-400W, the equal difference of the first 5 layers is gradually reduced, the power is kept unchanged, the height of each layer is 0.3mm, the diameter of a light spot is 1.0mm, the defocusing amount is 0.5mm, the scanning speed is 15mm/s, the shielding gas flow is 10L/min, the powder feeding amount is 10g/min, and Ar gas is adopted for the powder feeding gas and the shielding gas (the purity is more than 99.9%).

D5, after finishing the manufacture of one fin, rotating the stainless steel heat pipe by an angle of 18 degrees, and repeating the D4 fin deposition operation until all the fins are manufactured.

D6, milling the surface of the fin by a machining method, and polishing to obtain the finned heat pipe shell.

While the embodiments of the invention have been described in detail in connection with the accompanying drawings, it is not intended to limit the scope of the invention. Various modifications and changes may be made by those skilled in the art without inventive step within the scope of the appended claims.