阅读说明：本技术 一种高效保温隔热防锈蚀老化弯管的制备方法 (Preparation method of efficient heat-preservation, heat-insulation, anti-corrosion and aging-resistant bent pipe ) 是由 成典云 李林葳 赵立 于 2021-09-02 设计创作，主要内容包括：本发明公开了属于弯管技术领域的一种高效保温隔热防锈蚀老化弯管的制备方法。本发明的方法是采用低熔点石蜡作为金属内腔体的填充物,进而将金属直管材拉弯或绕弯成形为预定形状的弯管,之后将外侧包覆二氧化硅气凝胶毡的弯管在特种物料中侵泡、高温固化,最后在弯管外侧喷涂聚脲涂层。该制备方法,克服了现有技术中金属弯管弯曲成形后截面会出现的严重凹陷、凸起、褶皱等畸变,在使用过程中保温隔热性能差、渗漏、易锈蚀老化等问题,提高了金属弯管的弯曲成形质量,提升了金属弯管的保温隔热性能、防渗漏、耐锈蚀老化性能。(The invention discloses a preparation method of a high-efficiency heat-preservation, heat-insulation, corrosion-resistant and aging-resistant bent pipe, belonging to the technical field of bent pipes. The method of the invention adopts low melting point paraffin as the filler of the metal inner cavity, further forms the metal straight pipe into the bent pipe with the preset shape by stretch bending or winding bending, then soaks the bent pipe coated with the silica aerogel felt in the special material, solidifies at high temperature, and finally sprays the polyurea coating on the outer side of the bent pipe. The preparation method overcomes the defects of serious deformation of the cross section of the bent metal pipe, such as dent, bulge, fold and the like, poor heat insulation performance, leakage, easy corrosion and aging and the like after bending and forming in the prior art, improves the bending and forming quality of the bent metal pipe, and improves the heat insulation performance, leakage resistance, corrosion and aging resistance of the bent metal pipe.)

1. The preparation method of the high-efficiency heat-preservation heat-insulation rust-proof aging bent pipe is characterized by comprising the following steps of:

(1) taking a metal straight pipe with a certain length, and sealing and blocking the lower end of the metal straight pipe through a plug and other articles;

(2) placing the metal straight pipe in 100 ℃ boiling water, and exposing the upper end opening of the metal straight pipe out of the water surface;

(3) placing solid paraffin into the inner cavity of the metal straight pipe through the upper end opening of the metal straight pipe until the solid paraffin is completely melted and the upper surface of the liquid paraffin is close to the vicinity of the upper end opening of the metal straight pipe;

(4) stopping heating the boiling water, naturally cooling the metal straight pipe in the water to room temperature, and completely cooling and solidifying the paraffin in the inner cavity of the straight pipe;

(5) clamping a metal straight pipe on a stretch bender or a wrap bender for stretch bending or wrap bending to form a bent pipe with a preset shape;

(6) putting the bent pipe formed in the step (5) into 100 ℃ boiling water again with the open end facing downwards, and enabling the solid paraffin in the inner cavity of the bent pipe to be molten and automatically flow out;

(7) stopping heating the boiling water, naturally cooling the bent pipe in the water to 10-15 ℃ above the melting point temperature of the paraffin, taking out the bent pipe, naturally cooling the bent pipe in the air to room temperature, and sealing and blocking the opening end of the bent pipe;

(8) coating and fixing a layer of silica aerogel felt with the thickness of 1-5mm on the outer surface of the bent pipe obtained by the treatment in the step (7);

(9) preparing uniformly mixed materials according to the parts by weight, wherein: 100 parts of liquid epoxy resin, 5-15 parts of solid epoxy resin, 10-20 parts of alkaline catalyst, 5-10 parts of hollow ceramic microspheres, 5-10 parts of expandable microsphere foaming agent, 15-30 parts of high-temperature curing agent, 3-5 parts of accelerator and 2-5 parts of coupling agent, and placing the prepared mixed material on a vibration platform for later use;

(10) placing the bent pipe obtained by the treatment in the step (8) in the mixed material prepared in the step (9), starting a vibration platform, and enabling the vibration frequency to be 100 and 300HZ and the soaking and vibration time to be 0.5-1 h;

(11) taking out the bent pipe treated in the step (10), putting the bent pipe into a drying box for drying and curing, heating to 100-;

(12) spraying polyurea elastomer coating with the thickness of 0.5-2mm on the outer surface of the bent pipe obtained by the treatment in the step (11) by using a spray gun;

(13) and (4) taking out the two sealed and blocked ports of the bent pipe obtained by the treatment in the step (12) to obtain the required high-efficiency heat-preservation heat-insulation rust-proof ageing bent pipe.

2. The preparation method of the high-efficiency heat-preservation heat-insulation anti-corrosion aging elbow pipe as claimed in claim 1, wherein in the step (3), 1-6% by weight of polyisobutylene is added into paraffin wax; in the step (9), the alkaline catalyst is sodium hydroxide or potassium hydroxide, and the concentration range of the solution is 0.5-1.0 moL/L; hollow ceramic microspheres with diameter of 1-200 μm and density of 0.8-2.0g/cm³(ii) a The curing agent is a mixture of dicyandiamide and triethylene tetramine; the accelerant is one or more of UR500, benzyl dimethylamine and polyether amine; the coupling agent is one of KH550, KH560 and KH 570.

Technical Field

The invention relates to the technical field of bent pipes, in particular to a preparation method of a high-efficiency heat-preservation, heat-insulation, corrosion-resistant and aging-resistant bent pipe.

Background

The metal bent pipe is mainly applied to gas and liquid conveying pipelines, and is widely applied to the fields of aviation, aerospace, ships, automobiles, national defense and military industry and the like due to the fact that the metal bent pipe has a series of excellent characteristics of high specific strength, light weight, good heat dissipation performance and the like.

The processing and forming of the metal elbow fitting mainly comprises the steps of clamping a straight pipe on a stretch bender or a bending bender, and stretch bending or bending to form an elbow with a preset shape, but because the metal pipe is hollow and thin in wall thickness, the metal pipe deforms unevenly under the action of tensile and compressive stress in the bending forming process, has serious deformation such as dent, bulge, wrinkle and the like, and cannot meet the requirement of the high-precision section shape of the metal elbow fitting.

In addition, the heat conductivity coefficient of the common metal bent pipe is relatively large, the heat preservation and heat insulation performance is poor, and the common metal bent pipe is easy to oxidize and rust, so that the requirements of specific performances of heat preservation, heat insulation, leakage prevention, rust prevention, aging prevention and the like of the metal bent pipe in specific fields of aviation, aerospace, national defense and military industry and the like cannot be met.

The invention with the publication number of CN103861912A discloses a bending forming method of an aluminum alloy pipe; the method comprises the steps of putting small alloy metal blocks with low melting points into a straight pipe to be bent, melting the small metal blocks by heating, forming on a stretch bender or a wrap bender after cooling and solidification, and melting and automatically flowing out filling metal by heating. The aluminum alloy pipe bending forming device solves the problems of serious deformation such as sinking, protruding, wrinkling and the like of the section of the aluminum alloy pipe after bending forming. However, the low-melting-point alloy is used as a filler, so that the raw material cost is high, special preparation is required, and the operation steps are complicated; after the low-melting-point alloy is used as a filler to fill the inner cavity of the pipe, the quality and the rigidity of the pipe are increased by multiple times, so that the operation of the bending forming process is difficult; in addition, the phenomenon that low-melting-point alloy and impurities are adhered to the inner wall of the metal pipe body exists after the metal pipe is bent, formed and heated.

At present, the bending forming process of the pipe is improved in China, but the defects are obvious. The technical problem that the existing metal bent pipe field needs to be overcome urgently is how to overcome the problems that the cross section of a bent metal bent pipe can be seriously deformed such as concave, convex and fold, and the heat insulation performance is poor, leakage and corrosion and aging are easy to occur in the using process.

Disclosure of Invention

The invention aims to provide a preparation method of an efficient heat-preservation, heat-insulation and corrosion-resistant aging-resistant bent pipe, which overcomes the problems of serious deformation of a cross section of a bent metal pipe, such as dent, bulge, wrinkle and the like, poor heat-preservation and heat-insulation performance, leakage, easy corrosion and aging and the like after the bent metal pipe is bent and formed in the prior art, improves the bending and forming quality of the bent metal pipe, and improves the heat-preservation and heat-insulation performance, the leakage-prevention performance, the corrosion-resistant and aging-resistant performance of the bent metal pipe.

A preparation method of an efficient heat-preservation, heat-insulation, anti-corrosion and aging-resistant bent pipe comprises the following steps:

(1) taking a metal straight pipe with a certain length, and sealing and blocking the lower end of the metal straight pipe through a plug and other articles;

(2) placing the metal straight pipe in 100 ℃ boiling water, and exposing the upper end opening of the metal straight pipe out of the water surface;

(3) placing solid paraffin into the inner cavity of the metal straight pipe through the upper end opening of the metal straight pipe until the solid paraffin is completely melted and the upper surface of the liquid paraffin is close to the vicinity of the upper end opening of the metal straight pipe;

(4) stopping heating the boiling water, naturally cooling the metal straight pipe in the water to room temperature, and completely cooling and solidifying the paraffin in the inner cavity of the straight pipe;

(5) clamping a metal straight pipe on a stretch bender or a wrap bender for stretch bending or wrap bending to form a bent pipe with a preset shape;

(6) putting the bent pipe formed in the step (5) into 100 ℃ boiling water again with the open end facing downwards, and enabling the solid paraffin in the inner cavity of the bent pipe to be molten and automatically flow out;

(7) stopping heating the boiling water, naturally cooling the bent pipe in the water to 10-15 ℃ above the melting point temperature of the paraffin, taking out the bent pipe, naturally cooling the bent pipe in the air to room temperature, and sealing and blocking the opening end of the bent pipe;

(8) coating and fixing a layer of silica aerogel felt with the thickness of 1-5mm on the outer surface of the bent pipe obtained by the treatment in the step (7);

(9) preparing uniformly mixed materials according to the parts by weight, wherein: 100 parts of liquid epoxy resin, 5-15 parts of solid epoxy resin, 10-20 parts of alkaline catalyst, 5-10 parts of hollow ceramic microspheres, 5-10 parts of expandable microsphere foaming agent, 15-30 parts of high-temperature curing agent, 3-5 parts of accelerator and 2-5 parts of coupling agent, and placing the prepared mixed material on a vibration platform for later use;

(10) placing the bent pipe obtained by the treatment in the step (8) in the mixed material prepared in the step (9), starting a vibration platform, and enabling the vibration frequency to be 100 and 300HZ and the soaking and vibration time to be 0.5-1 h;

(11) taking out the bent pipe treated in the step (10), putting the bent pipe into a drying box for drying and curing, heating to 100-;

(12) spraying polyurea elastomer coating with the thickness of 0.5-2mm on the outer surface of the bent pipe obtained by the treatment in the step (11) by using a spray gun;

(13) and (4) taking out the two sealed and blocked ports of the bent pipe obtained by the treatment in the step (12) to obtain the required high-efficiency heat-preservation heat-insulation rust-proof ageing bent pipe.

Preferably, in the step (3), polyisobutylene with the mass part of 1-6% is added into the paraffin;

preferably, in the step (9), the alkaline catalyst is sodium hydroxide or potassium hydroxide, and the concentration range of the solution is 0.5-1.0 moL/L;

preferably, in the step (9), the hollow ceramic microspheres have a diameter of 1-200 μm and a density of 0.8-2.0g/cm³；

Preferably, in the step (9), the curing agent is a mixture of dicyandiamide and triethylene tetramine;

preferably, in the step (9), the accelerator is one or more of UR500, benzyldimethylamine and polyetheramine;

preferably, in the step (9), the coupling agent is one of KH550, KH560 and KH 570.

The invention has the beneficial effects that:

(1) before the metal bent pipe is bent and formed, solid paraffin is filled in the inner cavity of the metal straight pipe and sealed, so that the strength and hardness of the metal pipe are enhanced, the problems that the cross section of the metal pipe is seriously sunken, bulged, wrinkled and the like during bending and forming are solved, the cross section size of the metal bent pipe meets the precision requirement, and the processing efficiency and the qualified rate of the metal bent pipe are improved.

(2) Compared with the method using low-melting-point alloy as a filler, the method has the advantages that the cost of the paraffin is low, special preparation is not needed, the paraffin can be directly purchased and used in the market, and the operation steps are simple; in addition, after the metal pipe is bent, formed and heated, paraffin is melted and automatically flows out completely, and the phenomenon that low-melting-point alloy and impurities are adhered to the inner wall of the metal pipe body is avoided.

(3) After 1-6% of polyisobutylene in parts by weight is added into paraffin, the polyisobutylene can be well mixed with the molten paraffin, the shrinkage of the paraffin due to temperature change can be reduced, the toughness of the cooled and solidified paraffin can be greatly improved, and the paraffin is prevented from being brittle when a straight pipe is subjected to stretch bending or bending forming.

(4) The silicon dioxide aerogel felt is coated on the outer surface of the metal bent pipe, so that the heat preservation and heat insulation performance of the metal bent pipe is greatly improved, and the influence of the external temperature environment on the fluid in the inner cavity of the metal bent pipe is greatly reduced;

(5) the polyurea elastomer coating is sprayed on the outer surface of the silicon dioxide aerogel felt, and has good shear resistance, tear resistance, flexibility, adhesive force, higher elongation modulus, excellent water resistance, chemical corrosion resistance and aging resistance, good flexibility in a low-temperature environment and quick curing, so that the impact resistance, wear resistance, waterproof performance, aging resistance and corrosion resistance of the elbow are greatly improved, and the environmental adaptability of the elbow is improved.

(6) After the bent pipe coated with the silicon dioxide aerogel felt is soaked in the mixed material, the mixed material can be fully adhered to a gap between the metal bent pipe and the silicon dioxide aerogel felt, the gap is eliminated, a cross-linking curing reaction occurs in the drying and curing process, the bonding force between the surface of the metal bent pipe and the silicon dioxide aerogel felt is enhanced, the corrosion, aging and leakage of the outer surface of the metal pipe are prevented, and the heat preservation and insulation effects are enhanced; the composite foam generated under the action of each material has a fixing effect on the silica aerogel network framework and the particles, so that the mechanical strength of the silica aerogel felt is enhanced, the powder falling phenomenon of the silica aerogel felt is prevented, and the bonding strength of the silica aerogel felt and the polyurea coating is enhanced.

(7) The hollow ceramic microspheres are added into the mixed material, so that the mechanical strength of the silica aerogel felt is improved, the anti-radiation heat conduction capability is improved, and the convection heat conduction coefficient is reduced.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention.

Example 1

A preparation method of an efficient heat-preservation, heat-insulation, anti-corrosion and aging-resistant bent pipe comprises the following steps:

(1) taking a metal straight pipe with a certain length, and sealing and blocking the lower end of the metal straight pipe through a plug and other articles;

(2) placing the metal straight pipe in 100 ℃ boiling water, and exposing the upper end opening of the metal straight pipe out of the water surface;

(3) placing solid paraffin into the inner cavity of the metal straight pipe through the upper end opening of the metal straight pipe until the solid paraffin is completely melted and the upper surface of the liquid paraffin is close to the vicinity of the upper end opening of the metal straight pipe;

(4) stopping heating the boiling water, naturally cooling the metal straight pipe in the water to room temperature, and completely cooling and solidifying the paraffin in the inner cavity of the straight pipe;

(5) clamping a metal straight pipe on a stretch bender or a wrap bender for stretch bending or wrap bending to form a bent pipe with a preset shape;

(6) putting the bent pipe formed in the step (5) into 100 ℃ boiling water again with the open end facing downwards, and enabling the solid paraffin in the inner cavity of the bent pipe to be molten and automatically flow out;

(7) stopping heating the boiling water, naturally cooling the bent pipe in the water to a temperature higher than the melting point of paraffin by 10 ℃, taking out the bent pipe, naturally cooling the bent pipe in the air to room temperature, and sealing and blocking the opening end of the bent pipe;

(8) coating and fixing a layer of silica aerogel felt with the thickness of 1mm on the outer surface of the bent pipe obtained by the treatment in the step (7);

(9) preparing uniformly mixed materials according to the parts by weight, wherein: 100 parts of liquid epoxy resin, 5 parts of solid epoxy resin, 10 parts of an alkaline catalyst, 5 parts of hollow ceramic microspheres, 10 parts of an expandable microsphere foaming agent, 15 parts of a high-temperature curing agent, 5 parts of an accelerant and 3 parts of a coupling agent, and placing the prepared mixed material on a vibration platform for later use;

(10) placing the bent pipe obtained by the treatment in the step (8) in the mixed material prepared in the step (9), starting a vibration platform, and enabling the vibration frequency to be 100HZ and the soaking and vibration time to be 1 h;

(11) taking out the bent pipe treated in the step (10), putting the bent pipe into a drying oven for drying and curing, heating to 100 ℃, preserving heat for 2 hours, naturally cooling to 45 ℃, taking out the bent pipe, and cleaning the surface of the bent pipe;

(12) spraying polyurea elastomer paint with the thickness of 1mm on the outer surface of the bent pipe obtained by the treatment in the step (11) by using a spray gun;

(13) and (4) taking out the two sealed and blocked ports of the bent pipe obtained by the treatment in the step (12) to obtain the required high-efficiency heat-preservation heat-insulation rust-proof ageing bent pipe.

Wherein, in the step (3), polyisobutylene with the mass part of 4% is added into the paraffin; in the step (9), the alkaline catalyst is sodium hydroxide or potassium hydroxide, and the concentration range of the solution is 1.0 moL/L; the hollow ceramic microspheres have a diameter of 1-10 μm and a density of 1.86g/cm³(ii) a The curing agent is a mixture of dicyandiamide and triethylene tetramine, the accelerator is UR500, and the coupling agent is KH 560.

Example 2

A preparation method of an efficient heat-preservation, heat-insulation, anti-corrosion and aging-resistant bent pipe comprises the following steps:

(1) taking a metal straight pipe with a certain length, and sealing and blocking the lower end of the metal straight pipe through a plug and other articles;

(2) placing the metal straight pipe in 100 ℃ boiling water, and exposing the upper end opening of the metal straight pipe out of the water surface;

(3) placing solid paraffin into the inner cavity of the metal straight pipe through the upper end opening of the metal straight pipe until the solid paraffin is completely melted and the upper surface of the liquid paraffin is close to the vicinity of the upper end opening of the metal straight pipe;

(4) stopping heating the boiling water, naturally cooling the metal straight pipe in the water to room temperature, and completely cooling and solidifying the paraffin in the inner cavity of the straight pipe;

(5) clamping a metal straight pipe on a stretch bender or a wrap bender for stretch bending or wrap bending to form a bent pipe with a preset shape;

(6) putting the bent pipe formed in the step (5) into 100 ℃ boiling water again with the open end facing downwards, and enabling the solid paraffin in the inner cavity of the bent pipe to be molten and automatically flow out;

(7) stopping heating the boiling water, naturally cooling the bent pipe in the water to 12 ℃ above the melting point temperature of the paraffin, taking out the bent pipe, naturally cooling the bent pipe in the air to room temperature, and sealing and blocking the opening end of the bent pipe;

(8) coating and fixing a layer of silica aerogel felt with the thickness of 3mm on the outer surface of the bent pipe obtained by the treatment in the step (7);

(9) preparing uniformly mixed materials according to the parts by weight, wherein: 100 parts of liquid epoxy resin, 10 parts of solid epoxy resin, 15 parts of alkaline catalyst, 8 parts of hollow ceramic microspheres, 8 parts of expandable microsphere foaming agent, 25 parts of high-temperature curing agent, 4 parts of accelerator and 4 parts of coupling agent, and placing the prepared mixed material on a vibration platform for later use;

(10) placing the bent pipe obtained by the treatment in the step (8) in the mixed material prepared in the step (9), starting a vibration platform, and enabling the vibration frequency to be 200HZ and the soaking and vibration time to be 1.5 h;

(11) taking out the bent pipe treated in the step (10), putting the bent pipe into a drying oven for drying and curing, heating to 160 ℃, preserving heat for 1h, naturally cooling to 45 ℃, taking out the bent pipe, and cleaning the surface;

(12) spraying polyurea elastomer paint with the thickness of 1mm on the outer surface of the bent pipe obtained by the treatment in the step (11) by using a spray gun;

(13) and (4) taking out the two sealed and blocked ports of the bent pipe obtained by the treatment in the step (12) to obtain the required high-efficiency heat-preservation heat-insulation rust-proof ageing bent pipe.

Wherein, in the step (3), polyisobutylene with the mass part of 6% is added into the paraffin; in the step (9), the alkaline catalyst is sodium hydroxide or potassium hydroxide, the concentration range of the solution is 0.8moL/L, the diameter of the hollow ceramic microsphere is 10-50 μm, and the density is 1.08g/cm³(ii) a The curing agent is a mixture of dicyandiamide and triethylene tetramine, the accelerator is a mixture of UR500 and benzyl dimethylamine, and the coupling agent is KH 570.

Example 3

A preparation method of an efficient heat-preservation, heat-insulation, anti-corrosion and aging-resistant bent pipe comprises the following steps:

(1) taking a metal straight pipe with a certain length, and sealing and blocking the lower end of the metal straight pipe through a plug and other articles;

(2) placing the metal straight pipe in 100 ℃ boiling water, and exposing the upper end opening of the metal straight pipe out of the water surface;

(3) placing solid paraffin into the inner cavity of the metal straight pipe through the upper end opening of the metal straight pipe until the solid paraffin is completely melted and the upper surface of the liquid paraffin is close to the vicinity of the upper end opening of the metal straight pipe;

(4) stopping heating the boiling water, naturally cooling the metal straight pipe in the water to room temperature, and completely cooling and solidifying the paraffin in the inner cavity of the straight pipe;

(5) clamping a metal straight pipe on a stretch bender or a wrap bender for stretch bending or wrap bending to form a bent pipe with a preset shape;

(6) putting the bent pipe formed in the step (5) into 100 ℃ boiling water again with the open end facing downwards, and enabling the solid paraffin in the inner cavity of the bent pipe to be molten and automatically flow out;

(7) stopping heating the boiling water, naturally cooling the bent pipe in the water to 15 ℃ above the melting point temperature of the paraffin, taking out the bent pipe, naturally cooling the bent pipe in the air to room temperature, and sealing and blocking the opening end of the bent pipe;

(8) coating and fixing a layer of silica aerogel felt with the thickness of 4mm on the outer surface of the bent pipe obtained by the treatment in the step (7);

(9) preparing uniformly mixed materials according to the parts by weight, wherein: 100 parts of liquid epoxy resin, 13 parts of solid epoxy resin, 18 parts of basic catalyst, 8 parts of hollow ceramic microspheres, 10 parts of expandable microsphere foaming agent, 25 parts of high-temperature curing agent, 5 parts of accelerator and 2 parts of coupling agent, and placing the prepared mixed material on a vibration platform for later use;

(10) placing the bent pipe obtained by the treatment in the step (8) in the mixed material prepared in the step (9), starting a vibration platform, and enabling the vibration frequency to be 300HZ and the soaking and vibration time to be 1 h;

(11) taking out the bent pipe treated in the step (10), putting the bent pipe into a drying oven for drying and curing, heating to 140 ℃, preserving heat for 1.5h, naturally cooling to 45 ℃, taking out the bent pipe, and cleaning the surface;

(12) spraying polyurea elastomer paint with the thickness of 1.5mm on the outer surface of the bent pipe obtained by the treatment in the step (11) by using a spray gun;

(13) and (4) taking out the two sealed and blocked ports of the bent pipe obtained by the treatment in the step (12) to obtain the required high-efficiency heat-preservation heat-insulation rust-proof ageing bent pipe.

Wherein, in the step (3), polyisobutylene with the mass part of 5% is added into the paraffin; in the step (9), the alkaline catalyst is sodium hydroxide or potassium hydroxide, the concentration range of the solution is 1.0moL/L, the diameter of the hollow ceramic microsphere is 50-200 mu m, and the density is 0.96g/cm³(ii) a The curing agent is a mixture of dicyandiamide and triethylene tetramine, the accelerator is a mixture of benzyl dimethylamine and polyether amine, and the coupling agent is KH 550.

The above examples are intended to illustrate the technical solutions of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, but not to limit the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.