A solid-phase composite stainless steel / carbon steel bimetallic tube and its processing technology

Abstract

This invention relates to the field of stainless steel / carbon steel bimetallic composite pipe technology, and provides a solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology. The pipe includes a stainless steel pipe as an inner lining, a carbon steel pipe as an outer layer, and a transition copper layer between the stainless steel and carbon steel pipes. The components and percentages of the transition copper layer are as follows: 45-55% silver, 0-0.3% trace elements, and the balance copper. The solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology provided by this invention allow copper and silver atoms in the transition copper layer to diffuse onto the surfaces of the stainless steel and carbon steel pipes under certain pressure and temperature, thereby improving the interlayer bonding strength of the materials. The Fe and Mn elements in the transition copper layer can improve the strength of the materials. The Zn and Mg elements in the transition copper layer can alter the oxidation and coating density during spraying.

Description

Technical Field

[0001] This invention relates to the field of stainless steel / carbon steel bimetallic composite pipe technology, specifically to a solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology. Background Technology

[0002] Stainless steel / carbon steel bimetallic composite pipes are high-quality products used for drinking water transportation. Stainless steel serves as the inner lining, ensuring safety and hygiene and preventing secondary contamination. Carbon steel reinforces the outer wall, providing excellent resistance to compression and resonance, significantly reducing the likelihood of leakage due to external impacts. This avoids substantial water waste caused by leaks and extends the pipe's service life. Compared to single-material stainless steel or copper pipes, it offers superior overall performance and lower operating costs, making it highly cost-effective.

[0003] The manufacturing challenge of this type of bimetallic pipe lies in how to obtain higher interlayer bonding strength and sealing performance to prevent delamination during construction and use, which would affect water quality and material corrosion. To address this, this invention proposes a solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology. Summary of the Invention

[0004] The purpose of this invention is to provide a solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology, so as to solve the problem that the manufacturing difficulty of bimetallic pipes in the prior art lies in how to obtain higher interlayer bonding strength and sealing performance, and prevent delamination during construction and use, which affects water quality and material corrosion.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a solid-phase composite stainless steel / carbon steel bimetallic tube and its processing technology, comprising a stainless steel tube as an inner lining layer, a carbon steel tube as an outer layer, and a transition copper layer between the stainless steel tube and the carbon steel tube, wherein the components and percentage content of the transition copper layer are as follows:

[0006] 45-55% silver, 0-0.3% trace elements, and the balance is copper.

[0007] Preferably, the trace elements in the transition copper layer include Fe, Zn, Mn, and Mg; wherein the percentage of each component is 10% Fe, 50% Zn, 30% Mn, and 10% Mg.

[0008] Preferably, the thickness of the transition copper layer is 3-8 μm.

[0009] Preferably, the interlayer bonding strength between the transition copper layer and the stainless steel tube and carbon steel tube is ≥50MPa.

[0010] A processing technology for a solid-phase composite stainless steel / carbon steel bimetallic tube includes the following steps:

[0011] S1. First, the outer wall of the stainless steel tube is roughened using a laser texturing process, and then a transition copper layer is sprayed on.

[0012] S2, a stainless steel pipe coated with a transition copper layer is combined with a carbon steel pipe using a mechanical spinning process.

[0013] Preferably, after the roughening treatment in S1, the roughness of the outer wall of the stainless steel pipe is <Ra0.2.

[0014] Preferably, the carbon steel pipe needs to be heated to 180-260°C during the S2 composite process.

[0015] The present invention has at least the following beneficial effects:

[0016] (1) The present invention provides a solid-phase composite stainless steel / carbon steel bimetallic pipe and its processing technology. The resulting product has the advantages of high strength, good corrosion resistance and good sealing performance. It is used to transport drinking water and will not cause secondary pollution to the water body. It has good anti-seepage performance.

[0017] (2) The present invention provides a solid-phase composite stainless steel / carbon steel bimetallic tube and its processing technology. The copper and silver atoms in the transition copper layer can diffuse to the surface of the stainless steel tube and the carbon steel tube under certain pressure and temperature, thereby improving the interlayer bonding force of the material; the Fe and Mn elements in the transition copper layer can improve the strength of the material; the Zn and Mg elements in the transition copper layer can change the oxidation and coating density during spraying.

[0018] (3) The present invention provides a solid-phase composite stainless steel / carbon steel bimetallic tube and its processing technology, which uses laser texturing to texturize the stainless steel composite surface, and has an activating effect on the stainless steel surface spraying, which can obtain higher bonding strength.

[0019] (4) The present invention provides a solid-phase composite stainless steel / carbon steel bimetallic tube and its processing technology. The spinning process is adopted. Under the action of large compressive stress, it is beneficial for the metal atoms in the transition copper layer to diffuse to the surface of the stainless steel tube and the carbon steel tube. The carbon steel tube is preheated at 180-260℃, which can promote the diffusion of interlayer metals on the one hand, and improve the internal stress of stainless steel / steel bimetal after cooling and forming on the other hand, thereby improving the interlayer bonding force and the overall mechanical properties of the material. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the stainless steel / carbon steel bimetallic tube in this invention;

[0021] In the attached diagram, 11 represents a stainless steel pipe; 12 represents a transition copper layer; and 13 represents a carbon steel pipe. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] A solid-phase composite stainless steel / carbon steel bimetallic pipe includes a stainless steel pipe 11 as an inner lining layer, a carbon steel pipe 13 as an outer layer, and a transition copper layer 12 between the stainless steel pipe 11 and the carbon steel pipe 13. The components and percentage contents of the transition copper layer 12 are as follows:

[0025] 45% silver, 55% copper.

[0026] The thickness of the transition copper layer 12 is 3 μm.

[0027] The interlayer bonding strength between the transition copper layer 12 and the stainless steel pipe 11 and the carbon steel pipe 13 is ≥50MPa.

[0028] Example 2

[0029] A solid-phase composite stainless steel / carbon steel bimetallic pipe includes a stainless steel pipe 11 as an inner lining layer, a carbon steel pipe 13 as an outer layer, and a transition copper layer 12 between the stainless steel pipe 11 and the carbon steel pipe 13. The components and percentage contents of the transition copper layer 12 are as follows:

[0030] 50% silver, 0.15% total trace elements Fe, Zn, Mn, and Mg, and 49.85% copper.

[0031] The percentages of each trace element component are 10% Fe, 50% Zn, 30% Mn, and 10% Mg.

[0032] The thickness of the transition copper layer 12 is 6 μm.

[0033] The interlayer bonding strength between the transition copper layer 12 and the stainless steel pipe 11 and the carbon steel pipe 13 is ≥50MPa.

[0034] Example 3

[0035] A solid-phase composite stainless steel / carbon steel bimetallic pipe includes a stainless steel pipe 11 as an inner lining layer, a carbon steel pipe 13 as an outer layer, and a transition copper layer 12 between the stainless steel pipe 11 and the carbon steel pipe 13. The components and percentage contents of the transition copper layer 12 are as follows:

[0036] 55% silver, 0.3% total trace elements Fe, Zn, Mn, and Mg, and 44.7% copper.

[0037] The percentages of each trace element component are 10% Fe, 50% Zn, 30% Mn, and 10% Mg.

[0038] The thickness of the transition copper layer 12 is 8 μm.

[0039] The interlayer bonding strength between the transition copper layer 12 and the stainless steel pipe 11 and the carbon steel pipe 13 is ≥50MPa.

[0040] The processing technology for a solid-phase composite stainless steel / carbon steel bimetallic tube provided in Examples 1-3 above includes the following steps:

[0041] S1. First, the outer wall of the stainless steel tube 11 is roughened using a laser roughening process. The roughness of the outer wall of the stainless steel tube 11 is <Ra0.2. Then, a transition copper layer 12 is sprayed on.

[0042] S2, the stainless steel pipe 11 with the sprayed transition copper layer 12 is combined with the carbon steel pipe 13 by mechanical spinning process. During the combination process, the carbon steel pipe 13 needs to be heated to 180-260℃.

[0043] In this invention, under the conditions of the spinning composite process, the deformation is limited to a certain extent, and the diffusion at the interface between the stainless steel pipe 11 and the carbon steel pipe 13 is not sufficient, resulting in a slightly insufficient bonding force. Copper and silver atoms can diffuse onto the surfaces of the two materials under certain pressure and temperature, thereby improving the interlayer bonding force. Considering the corrosion resistance, mechanical properties, and biocompatibility of the intermediate layer, an optimal silver content of 45-55% was selected through experiments. Furthermore, Fe and Mn elements were added to the transition copper layer 12 to improve the strength of the material, and Zn and Mg elements were added to change the oxidation and coating density during spraying. These factors all affect the bonding force of the transition copper layer 12 as a transition layer. In addition, considering the influence of these elements on the corrosion performance of the transition copper layer 12 and even the substrates of the stainless steel pipe 11 and the carbon steel pipe 13, as well as the biocompatibility and the impact on water quality, these trace alloying elements were limited to the range of 0-0.3% through experiments.

[0044] Because a dense protective film easily forms on the surface of stainless steel tube 11, atomic diffusion between stainless steel tube 11 and carbon steel tube 13 is suppressed, which is not conducive to forming a strong metallurgical bond. This invention uses laser texturing to texturize the composite surface of stainless steel tube 11. By texturing the stainless steel surface, the diffusion temperature can be significantly reduced, and significant diffusion can be achieved at 180-260℃. In addition, it was found that low-power laser has an activating effect on the surface coating of stainless steel tube 11, which can obtain higher bonding strength. Laser texturing is generally used to modify the microstructure of hard metal surfaces to improve the friction coefficient and other surface properties of the material. This invention has been optimized, and experiments have shown that when the roughness is <Ra0.2, the copper alloy deposited on the texturized stainless steel tube 11 surface has an anti-penetration effect and forms diffusion perpendicular to the stainless steel surface, thus improving the bonding strength of the coating.

[0045] Under the spinning process, the greater compressive stress is conducive to the diffusion of metal atoms in the transition copper layer 12 to the surfaces of the stainless steel tube 11 and the carbon steel tube 13. The diffusion conditions further optimized by this invention adopt a preheating temperature of 180-260℃, which can promote the diffusion of interlayer metals on the one hand, and improve the internal stress of the stainless steel / steel bimetal after cooling and forming on the other hand, thereby improving the interlayer bonding force and the overall mechanical properties of the material. According to experimental tests, the interlayer bonding force is ≥50MPa, and the yield strength of the bimetal is more than 10% higher than that of the single-material carbon steel material.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solid phase compounded stainless steel / carbon steel bimetallic pipe, characterized by, The stainless steel pipe (11) is an inner layer, the outside of the stainless steel pipe (11) is provided with a carbon steel pipe (13), the carbon steel pipe (13) is an outer layer, a transition copper layer (12) is arranged between the stainless steel pipe (11) and the carbon steel pipe (13), and components and percentage contents of the transition copper layer (12) are as follows: 45-55% silver, 0-0.3% trace elements, and the balance copper; The trace elements in the transition copper layer (12) include Fe, Zn, Mn and Mg, and the percentage of each component of the trace elements is 10% Fe, 50% Zn, 30% Mn and 10% Mg.

2. The solid phase composite stainless steel / carbon steel bimetallic tube according to claim 1, wherein The thickness of the transition copper layer (12) is 3-8 microns.

3. The solid phase composite stainless steel / carbon steel bimetallic tube according to claim 1, wherein The interlayer bonding force between the transition copper layer (12) and the stainless steel pipe (11) and the carbon steel pipe (13) is greater than or equal to 50 MPa.

4. The process for manufacturing a solid-phase-composited stainless steel / carbon steel bimetallic pipe according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: S1, first, the outer wall of the stainless steel pipe (11) is roughened by using a laser roughening process, and then the transition copper layer (12) is sprayed; S2, the stainless steel pipe (11) with the sprayed transition copper layer (12) is combined with the carbon steel pipe (13) by using a mechanical spinning process.

5. The process for processing a solid phase compounded stainless steel / carbon steel bimetallic pipe according to claim 4, characterized in that, After the roughening treatment in the S1, the roughness of the outer wall of the stainless steel pipe (11) is less than Ra0.

2.

6. The process for processing a solid phase compounded stainless steel / carbon steel bimetallic pipe according to claim 4, wherein In the S2, the carbon steel pipe (13) needs to be heated to 180-260 DEG C. In the S2, the carbon steel pipe (13) needs to be heated to 180-260 DEG C.

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