High-hardness antibacterial stainless steel composite pipe and preparation method thereof

Abstract

The invention relates to the technical field of composite pipes, and provides a high-hardness antibacterial stainless steel composite pipe and a preparation method thereof. The preparation method comprises the following steps that S1, copper-based brazing filler metal is arranged on the surface of a copper pipe, and the pretreated copper pipe is obtained; s2, the pretreated copper pipe is inserted into a stainless steel pipe, one end of the copper pipe is sealed, and a sealed steel pipe is obtained; and S3, the seal welding steel pipe is vacuumized, heated and cooled to the room temperature, and the high-hardness antibacterial stainless steel composite pipe is obtained. Heating comprises three stages, in the first stage, the heating rate is 18-24 DEG C / min, the temperature is increased to 300-360 DEG C, and the temperature is kept for 0.5-1 h, in the second stage, the heating rate is 28-32 DEG C / min, the temperature is increased to 680-730 DEG C, and the temperature is kept for 1-2 h, and in the third stage, the heating rate is 10-18 DEG C / min, the temperature is increased to 920-980 DEG C, and the temperature is kept for 1-2 h. Through the technical scheme, the problem of poor hardness of the stainless steel composite pipe in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite pipes, and in particular to a high-hardness antibacterial stainless steel composite pipe and a preparation method thereof. Background Art

[0002] In modern society, the reliance on pipes in various fields such as construction, industrial production, and daily life is increasing day by day. From the water supply and drainage systems of high-rise buildings to the complex material transportation pipelines in factories, stainless steel composite pipes are increasingly used. Traditional stainless steel composite pipes, with their own certain hardness, have met the needs of most common scenarios for a long time.

[0003] However, with the continuous development and progress of various industries, some special scenarios have put forward extremely stringent requirements on the performance of pipes. Take the food processing industry as an example. In the production, storage and transportation of food, materials need to be transported efficiently and stably through stainless steel composite pipes. This not only requires the stainless steel composite pipe to be able to withstand greater pressure, but also ensure that there will be no leakage, blockage and other problems during the transportation process of materials, to ensure the continuity of production, and to prevent food safety accidents caused by contamination due to pipe breakage.

[0004] In thermal power plants, boiler steam pipes and water supply pipes are exposed to high temperature and high pressure working environments. High-hardness antibacterial stainless steel composite pipes can be used for these pipes. With their high hardness, they can withstand the pressure of steam and water and prevent pipe deformation or bursting. In the past, stainless steel composite pipes usually adopted a simple structural combination method, trying to improve hardness by superimposing the advantages of different materials. However, this method is often restricted by many factors, resulting in very limited hardness improvement effects.

[0005] In summary, improving the hardness of stainless steel composite pipes is of vital importance to all walks of life. Summary of the invention

[0006] The invention provides a high-hardness antibacterial stainless steel composite pipe and a preparation method thereof, which solves the problem of poor hardness of the stainless steel composite pipe in the related art.

[0007] The technical solution of the present invention is as follows: The present invention provides a method for preparing a high-hardness antibacterial stainless steel composite tube, comprising the following steps: S1, setting a copper-based solder on the surface of the copper tube to obtain a pretreated copper tube; S2, inserting the pretreated copper tube into the stainless steel tube, and sealing one end to obtain a sealed welded steel tube; S3, evacuating the sealed welded steel pipe, heating it, and cooling it to room temperature to obtain a high-hardness antibacterial stainless steel composite pipe; The heating includes three stages. In the first stage, the heating rate is 18 - 24 °C / min, the temperature is raised to 300 - 360 °C, and it is kept warm for 0.5 - 1 h. In the second stage, the heating rate is 28 - 32 °C / min, the temperature is raised to 680 - 730 °C, and it is kept warm for 1 - 2 h. In the third stage, the heating rate is 10 - 18 °C / min, the temperature is raised to 920 - 980 °C, and it is kept warm for 1 - 2 h.

[0008] As a further technical solution, the copper tube is composed of the following elements by weight percentage: 0.5% - 1.2% zinc, 0.6% - 1.0% magnesium, 1.3% - 1.6% iron, and the balance is copper and inevitable impurities; The thickness of the copper tube is 0.4 - 0.6 mm.

[0009] As a further technical solution, the copper-based brazing filler metal is composed of the following elements by weight percentage: 3% - 8% tin, 8% - 24% antimony, 5% - 20% zirconium, 10% - 18% nickel, and the balance is copper.

[0010] In the present invention, by adding antimony and zirconium to the copper-based brazing filler metal simultaneously, the shear strength of the bonding force of the stainless steel composite pipe is improved.

[0011] As a further technical solution, the mass ratio of antimony to zirconium is 2 - 4:1.

[0012] In the present invention, by adjusting the mass ratio of antimony to zirconium to 2 - 4:1, the shear strength of the bonding force of the stainless steel composite pipe is further improved.

[0013] As a further technical solution, the mass ratio of antimony to zirconium is 3:1.

[0014] In the present invention, by adjusting the mass ratio of antimony to zirconium to 3:1, the shear strength of the bonding force of the stainless steel composite pipe is further improved.

[0015] As a further technical solution, the preparation method of the copper-based brazing filler metal includes the following steps: A1. Weigh the components according to the composition of the copper-based brazing filler metal, and after mixing evenly, obtain a mixture; A2. Pour the melted mixture into a mold and cool it to form an alloy bar; A3. Heat-treat the alloy bar and atomize it to make powder to obtain the copper-based brazing filler metal; The steps of the heat treatment include: raising the temperature to 880 - 900 °C, keeping it warm for 0.2 - 1.5 h and then cooling to room temperature.

[0016] As a further technical solution, when setting the copper-based brazing filler metal, the thickness is 30 - 40 μm.

[0017] As a further technical solution, the stainless steel pipe is composed of the following elements by weight percentage: 0.028% - 0.07% carbon, 18.0% - 20.0% chromium, 8.0% - 10.5% nickel, 0.05% - 0.9% manganese, 3.4% - 4.2% copper, 0.0002% - 0.0045% sulfur, 0.0003% - 0.008% phosphorus, and the balance is iron and inevitable impurities.

[0018] In the present invention, the weight percentage of copper in the stainless steel is 3.4% - 4.2%, which has a good antibacterial effect.

[0019] As a further technical solution, the seal welding is argon arc welding, the welding current is 30A, and the gas flow rate is 10L / min.

[0020] In the present invention, the seal welding current is 30A, the gas flow rate is 10L / min, the weld metal crystallizes well, the grains are fine and uniform, and the welded part is not prone to cracking or breaking, thus ensuring the structural integrity and safety of the pipeline.

[0021] As a further technical solution, the seal welding is argon arc welding, the welding current is 30A, and the gas flow rate is 10L / min; when evacuating, the cold vacuum degree < 3×10 -2 Pa; during the heating process, the air pressure is adjusted to 0.8 - 1.2MPa.

[0022] The present invention also provides a high-hardness antibacterial stainless steel composite pipe, which is prepared by the preparation method of a high-hardness antibacterial stainless steel composite pipe described above.

[0023] The working principle and beneficial effects of the present invention are as follows: In the present invention, during the preparation process of the composite pipe, through a specific heating strategy, the grain structure of the stainless steel composite pipe is optimized to be more dense and uniform, so that the stainless steel composite pipe can effectively resist external forces, thereby improving the hardness of the antibacterial stainless steel composite pipe. Specific embodiments

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0025] Example 1 A preparation method of a high-hardness antibacterial stainless steel composite pipe includes the following steps: S1. Apply a copper-based brazing filler metal with a thickness of 40 μm on the surface of a copper tube with a thickness of 0.6 mm to obtain a pre-treated copper tube; S2. Insert the pre-treated copper tube into a stainless steel tube and seal-weld one end to obtain a sealed-welded steel tube; S3. Evacuate the sealed-welded steel tube, heat it, and cool it to room temperature to obtain a high-hardness antibacterial stainless steel composite tube; The heating includes three stages. In the first stage, the heating rate is 24 °C / min, and it is heated to 360 °C and held for 0.5 h. In the second stage, the heating rate is 32 °C / min, and it is heated to 730 °C and held for 1 h. In the third stage, the heating rate is 18 °C / min, and it is heated to 980 °C and held for 1 h; The copper tube is composed of the following elements by weight percentage: 1.2% zinc, 1.0% magnesium, 1.6% iron, and the balance is copper and unavoidable impurities; The copper-based brazing filler metal is composed of the following elements by weight percentage: 8% tin, 15% antimony, 18% nickel, and the balance is copper; The preparation method of the copper-based brazing filler metal includes the following steps: A1. Weigh the components according to the composition of the copper-based brazing filler metal, and mix them evenly to obtain a mixed material; A2. Pour the melted mixed material into a mold, cool it, and make it into an alloy bar; A3. Heat-treat the alloy bar, atomize it to make powder, and obtain the copper-based brazing filler metal; The steps of the heat treatment include: heating to 900 °C, holding for 0.2 h, and then cooling to room temperature; The stainless steel tube is composed of the following elements by weight percentage: 0.07% carbon, 20.0% chromium, 10.5% nickel, 0.9% manganese, 4.2% copper, 0.0045% sulfur, 0.008% phosphorus, and the rest is iron and unavoidable impurities; The seal-welding is argon arc welding, the welding current is 30 A, and the gas flow rate is 10 L / min; When evacuating, the cold vacuum degree is 2×10 -2 Pa; During the heating process, adjust the air pressure to 1.2 MPa.

[0026] Example 2 A preparation method of a high-hardness antibacterial stainless steel composite tube includes the following steps: S1. Apply a copper-based brazing filler metal with a thickness of 30 μm on the surface of a copper tube with a thickness of 0.4 mm to obtain a pre-treated copper tube; S2. Insert the pre-treated copper tube into a stainless steel tube and seal-weld one end to obtain a sealed-welded steel tube; S3. Evacuate the sealed-welded steel tube, heat it, and cool it to room temperature to obtain a high-hardness antibacterial stainless steel composite tube; The heating process includes three stages. In the first stage, the heating rate is 18 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 28 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 10 °C / min, and the temperature is raised to 920 °C and held for 2 h; The copper tube is composed of the following elements by weight percentage: 0.5% zinc, 0.6% magnesium, 1.3% iron, and the balance is copper and inevitable impurities; The copper-based filler metal is composed of the following elements by weight percentage: 3% tin, 15% antimony, 10% nickel, and the balance is copper; The preparation method of the copper-based filler metal includes the following steps: A1. Weigh the components according to the composition of the copper-based filler metal, and after mixing evenly, obtain a mixed material; A2. Pour the melted mixed material into a mold and cool it to form an alloy rod; A3. Heat-treat the alloy rod, atomize it into powder to obtain the copper-based filler metal; The steps of the heat treatment include: raising the temperature to 880 °C, holding for 1.5 h and then cooling to room temperature; The stainless steel tube is composed of the following elements by weight percentage: 0.028% carbon, 18.0% chromium, 8.0% nickel, 0.05% manganese, 3.4% copper, 0.0002% sulfur, 0.0003% phosphorus, and the rest is iron and inevitable impurities; The seal welding is argon arc welding, the welding current is 30 A, and the gas flow rate is 10 L / min; When evacuating, the cold vacuum degree is 1×10 -2 Pa; During the heating process, adjust the air pressure to 0.8 MPa.

[0027] Example 3 A preparation method of a high-hardness antibacterial stainless steel composite tube includes the following steps: S1. Apply the copper-based filler metal with a thickness of 35 μm on the surface of the copper tube with a thickness of 0.5 mm to obtain a pretreated copper tube; S2. Insert the pretreated copper tube into the stainless steel tube and seal-weld one end to obtain a seal-welded steel tube; S3. Evacuate the seal-welded steel tube, heat it, and cool it to room temperature to obtain a high-hardness antibacterial stainless steel composite tube; The heating process includes three stages. In the first stage, the heating rate is 21 °C / min, and the temperature is raised to 320 °C and held for 0.6 h. In the second stage, the heating rate is 30 °C / min, and the temperature is raised to 700 °C and held for 1.5 h. In the third stage, the heating rate is 14 °C / min, and the temperature is raised to 960 °C and held for 1.5 h; The copper tube is composed of the following elements by weight percentage: 0.9% zinc, 0.8% magnesium, 1.5% iron, the balance being copper and unavoidable impurities; The copper-based filler metal is composed of the following elements by weight percentage: 5% tin, 15% antimony, 14% nickel, the balance being copper; The preparation method of the copper-based filler metal comprises the following steps: A1. Weigh the components according to the composition of the copper-based filler metal, and after mixing evenly, obtain a mixed material; A2. Pour the melted mixed material into a mold, cool it, and make an alloy bar; A3. Heat-treat the alloy bar, atomize it to make powder, and obtain the copper-based filler metal; The steps of the heat treatment include: heating to 890 °C, holding for 1 h, and then cooling to room temperature; The stainless steel tube is composed of the following elements by weight percentage: 0.04% carbon, 19.0% chromium, 9.0% nickel, 0.4% manganese, 3.8% copper, 0.0008% sulfur, 0.005% phosphorus, the rest being iron and unavoidable impurities; The seal welding is argon arc welding, the welding current is 30 A, and the gas flow rate is 10 L / min; When evacuating, the cold vacuum degree is 1.5×10 -2 Pa; During the heating process, adjust the air pressure to 1 MPa.

[0028] Example 4 The difference between this example and Example 3 is only that the copper-based filler metal in this example comprises the following components by weight percentage: 5% tin, 15% zirconium, 14% nickel, the balance being copper.

[0029] Example 5 The difference between this example and Example 3 is only that the copper-based filler metal in this example comprises the following components by weight percentage: 5% tin, 12.5% antimony, 2.5% zirconium, 14% nickel, the balance being copper.

[0030] Example 6 The difference between this example and Example 3 is only that the copper-based filler metal in this example comprises the following components by weight percentage: 5% tin, 7.5% antimony, 7.5% zirconium, 14% nickel, the balance being copper.

[0031] Example 7 The difference between this example and Example 3 is only that the copper-based filler metal in this example comprises the following components by weight percentage: 5% tin, 10% antimony, 5% zirconium, 14% nickel, the balance being copper.

[0032] Example 8 The difference between this embodiment and Embodiment 3 is only that the copper-based solder in this embodiment comprises the following components by weight percentage: 5% tin, 11.25% antimony, 3.75% zirconium, 14% nickel, and the balance is copper.

[0033] Embodiment 9 The difference between this embodiment and Embodiment 3 is only that the copper-based solder in this embodiment comprises the following components by weight percentage: 5% tin, 12% antimony, 3% zirconium, 14% nickel, and the balance is copper.

[0034] Comparative Example 1 The difference between this comparative example and Embodiment 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 17 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 28 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 10 °C / min, and the temperature is raised to 920 °C and held for 2 h.

[0035] Comparative Example 2 The difference between this comparative example and Embodiment 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 25 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 28 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 10 °C / min, and the temperature is raised to 920 °C and held for 2 h.

[0036] Comparative Example 3 The difference between this comparative example and Embodiment 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 18 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 27 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 10 °C / min, and the temperature is raised to 920 °C and held for 2 h.

[0037] Comparative Example 4 The difference between this comparative example and Embodiment 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 18 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 33 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 10 °C / min, and the temperature is raised to 920 °C and held for 2 h.

[0038] Comparative Example 5 The difference between this comparative example and Embodiment 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 18 °C / min, and the temperature is raised to 300 °C and held for 1 h. In the second stage, the heating rate is 28 °C / min, and the temperature is raised to 680 °C and held for 2 h. In the third stage, the heating rate is 9 °C / min, and the temperature is raised to 920 °C and held for 2 h.

[0039] Comparative Example 6 The difference between this comparative example and Example 2 is only that the heating in this comparative example includes three stages. In the first stage, the heating rate is 18 °C / min, the temperature is raised to 300 °C, and it is kept warm for 1 h. In the second stage, the heating rate is 28 °C / min, the temperature is raised to 680 °C, and it is kept warm for 2 h. In the third stage, the heating rate is 19 °C / min, the temperature is raised to 920 °C, and it is kept warm for 2 h.

[0040] Experimental Example 1 The hardness of the high-hardness antibacterial stainless steel composite pipes prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was tested according to the method in GB / T 31940-2015 "Dual-metal composite corrosion-resistant steel pipes for fluid transportation". Among them, the test force was 30 kgf and the holding time was 20 s. The test results are shown in Table 1.

[0041]

[0042] Comparing Example 2 with Comparative Examples 1 to 6 shows that the selection of a specific heating strategy in the present invention improves the hardness of the antibacterial stainless steel.

[0043] Experimental Example 2 The shear strength of the bonding force of the high-hardness antibacterial stainless steel composite pipes prepared in Examples 3 to 9 was tested according to the method in GB / T 31940-2015 "Dual-metal composite corrosion-resistant steel pipes for fluid transportation". The test results are shown in Table 2.

[0044]

[0045] Comparing Examples 5 to 9 with Examples 3 to 4 shows that adding antimony and zirconium simultaneously to the brazing filler metal in the present invention further improves the shear strength of the bonding force of the high-hardness antibacterial stainless steel composite pipe. Comparing Examples 7 to 9 with Examples 5 to 6 shows that when the mass ratio of antimony to zirconium is 2 to 4:1, the shear strength of the bonding force of the high-hardness antibacterial stainless steel composite pipe is further improved.

[0046] Experimental Example 3 The antibacterial performance of the stainless steel composite pipe prepared in Example 1 was tested against Escherichia coli and Staphylococcus aureus according to the method in GB / T 42675-2023 "Antibacterial stainless steel welded pipes and fittings". Among them, the wet detection method was selected, and the selected concentrations of the bacterial suspension were 2.0×10 5 CFU / mL. The results show that the antibacterial rate of the stainless steel composite pipe prepared in Example 1 against Escherichia coli is 99.7% and against Staphylococcus aureus is 99.9%.

[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-hardness antibacterial stainless steel composite tube, characterized in that: The following steps are involved: S1, setting a copper-based solder on the surface of the copper tube to obtain a pretreated copper tube; S2, inserting the pretreated copper tube into the stainless steel tube, and sealing one end to obtain a sealed welded steel tube; S3, evacuating the sealed welded steel pipe, heating it, and cooling it to room temperature to obtain a high-hardness antibacterial stainless steel composite pipe; The heating includes three stages. In the first stage, the heating rate is 18-24°C / min, the temperature is raised to 300-360°C, and the temperature is kept for 0.5-1h. In the second stage, the heating rate is 28-32°C / min, the temperature is raised to 680-730°C, and the temperature is kept for 1-2h. In the third stage, the heating rate is 10-18°C / min, the temperature is raised to 920-980°C, and the temperature is kept for 1-2h.

2. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 1, characterized in that: The copper tube is composed of the following elements in percentage by weight: 0.5% to 1.2% zinc, 0.6% to 1.0% magnesium, 1.3% to 1.6% iron, and the remainder is copper and unavoidable impurities; The copper tube has a thickness of 0.4-0.6 mm.

3. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 1, characterized in that: The copper-based solder is composed of the following elements in percentage by weight: 3% to 8% tin, 8% to 24% antimony, 5% to 20% zirconium, 10% to 18% nickel, and the balance is copper.

4. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 3, characterized in that: The mass ratio of antimony to zirconium is 2-4:

1.

5. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 4, characterized in that: The mass ratio of antimony to zirconium is 3:

1.

6. The method for preparing a high-hardness antibacterial stainless steel composite tube according to any one of claims 3 to 5, characterized in that: The preparation method of the copper-based solder comprises the following steps: A1. Prepare ingredients according to the copper-based solder components and mix them evenly to obtain a mixture; A2, melting the mixture and pouring it into a mold, cooling it, and making an alloy rod; A3, heat treating the alloy rod, atomizing and powdering, to obtain the copper-based solder; The heat treatment step includes: heating to 880-900° C., keeping the temperature for 0.2-1.5 hours, and then cooling to room temperature.

7. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 1, characterized in that: When the copper-based solder is provided, the thickness is 30-40 μm.

8. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 1, characterized in that: The stainless steel pipe is composed of the following elements in percentage by weight: 0.028% to 0.07% carbon, 18.0% to 20.0% chromium, 8.0% to 10.5% nickel, 0.05% to 0.9% manganese, 3.4% to 4.2% copper, 0.0002% to 0.0045% sulfur, 0.0003% to 0.008% phosphorus, and the rest is iron and unavoidable impurities.

9. The method for preparing a high-hardness antibacterial stainless steel composite tube according to claim 1, characterized in that: The sealing welding is argon arc welding, the welding current is 30A, and the gas flow rate is 10L / min; when the vacuum is drawn, the cold vacuum degree is less than 3×10 - 2 Pa; during the heating process, the gas pressure is adjusted to 0.8~1.2MPa.

10. A high-hardness antibacterial stainless steel composite tube, characterized in that: The high-hardness antibacterial stainless steel composite tube is prepared by the preparation method of any one of claims 1 to 9.

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