Iron-based powder porous surface heat-exchanging tube and manufacture method thereof

A porous surface, iron-based powder technology, used in heat exchange equipment, lighting and heating equipment, tubular components, etc., can solve the problems of deterioration of the matrix tube structure, difficulty in meeting the heat exchange tube, and reduced mechanical properties, and achieve high mechanical strength. change, low cost, and the effect of reducing the sintering temperature

Active Publication Date: 2008-08-27
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Excessive sintering temperature will inevitably deteriorate the structure of the base pipe, reduce the mechanical properties, and even bend and deform, making it difficult to meet the relevant standards for heat exchange tubes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Coat 1kg of polystyrene-based binder and 250 meshes of 5Kg iron-based alloy powder (Fe89Cu10P1) on the inner surface of a 20G heat exchange tube with a coating thickness of 0.4mm, dry the binder, and then sinter The reducing gas such as hydrogen is passed through the furnace, and the binder is decomposed at 350°C for 20 minutes, and then heated to 800°C for sintering for 20 minutes, and then the temperature is lowered to below 50°C to obtain a porous iron-based alloy surface tube; the thickness of the porous layer is 0.3mm, and the pores The ratio is 60%, and the equivalent pore size is 80μm.

[0025] Using acetone to measure the boiling heat transfer coefficient, the boiling heat transfer coefficient of the porous surface is 10 times that of the light tube, and the electric heating water is used as the experimental medium, and the boiling heat transfer coefficient is 4 times that of the same smooth surface.

Embodiment 2

[0027] Coat 1kg polystyrene-based binder and 300 mesh 5kg iron-based alloy powder (Fe80Ni18P2) on the outer surface of the 15CrMo heat exchange tube with a coating thickness of 0.4mm, dry the binder, and then place it in the sintering furnace Through hydrogen and other reducing gases, heat at 350°C for 20 minutes to decompose the binder, then heat up to 950°C for sintering for 20 minutes, then immediately take it out of the furnace and cool it in air, and the temperature drops below 50°C to obtain an iron-based alloy porous surface tube; the thickness of the porous layer is 0.3 mm, the porosity is 40%, and the equivalent pore diameter is 50 μm.

[0028] Using acetone to measure the boiling heat transfer coefficient, the boiling heat transfer coefficient of the porous surface is 11 times that of the light tube, and the electric heating water is used as the experimental medium, and the boiling heat transfer coefficient is 3.5 times that of the same smooth surface.

Embodiment 3

[0030] Coat 1kg of polystyrene-based binder and 300-mesh 5Kg iron-based alloy powder (Fe81Sn18S1) on the inner surface of a 20G heat exchange tube with a coating thickness of 0.4mm, dry the binder, and then sinter The reducing gas such as hydrogen is passed through the furnace, and the binder is decomposed at 350°C for 20 minutes, and then the temperature is raised to 880°C for sintering for 10 minutes, and then the temperature is lowered to below 50°C to obtain an iron-based alloy porous surface tube; the thickness of the porous layer is 0.3mm, and the pores The ratio is 50%, and the equivalent pore diameter is 70 μm.

[0031] Using acetone to measure the boiling heat transfer coefficient, the boiling heat transfer coefficient of the porous surface is 14 times that of the light tube, and the electric heating water is used as the experimental medium, and the boiling heat transfer coefficient is 4 times that of the same smooth surface.

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PUM

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Abstract

The invention discloses an iron-based powder porous surface heat exchange tube and a preparation method thereof. The heat exchange tube is formed by a tube base body and a porous surface layer; the porous surface layer takes fine grained power of iron or an iron alloy as the main composition, contains a low melting point alloy element and is formed by sintering; the porous surface layer can be positioned at any side of the inner side and the outer side of the tube, the other corresponding side can be a smooth surface or a structure provided with an enhanced condensing characteristic. The preparation method is that: an organic bonding agent and metal powder of an iron-based alloy are evenly mixed; the mixture is coated on the outer surface or the inner surface of the tube; the coated tube is dried; the tube is sent into a sintering furnace to decompose the organic bonding agent; the tube is sintered under the temperature not higher than the regular normalizing or annealing heat treatment temperature of the material; the speed of temperature reduction is controlled to assure the structure and the mechanical property required by the heat exchange tube. The heat exchange tube and the preparation method have the advantages that: the sintering temperature is lower, the mechanical performance of the tube material is basically unchanged, and the heat exchange tube has high efficiency and low cost, and can meet the requirement of the industrialized application.

Description

【Technical field】 [0001] The invention relates to the field of heat exchange tubes and their manufacture, specifically, a layer of iron-based metal powder porous layer is sintered on the inner surface or outer surface of the heat exchange tubes and its preparation method. 【Background technique】 [0002] The porous surface can significantly enhance the boiling heat transfer of water, freon, liquid nitrogen, olefins, benzene, petroleum, ethanol and other working fluids. Therefore, high-flux heat exchange tubes with porous surfaces are used in various heat transfer processes with phase transitions, such as vaporizers, evaporators, reboilers, condensers, etc., for their excellent boiling heat transfer performance in petroleum, chemical industry , metallurgy and other fields have broad application prospects. [0003] According to the heat transfer enhancement mechanism of porous surface, a large number of connected pores with appropriate size is the decisive factor to ensure eff...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F28F1/00F28F13/18B22F7/04B22F5/12
Inventor 刘京雷徐宏王学生张莉侯峰吴健
Owner EAST CHINA UNIV OF SCI & TECH
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