Wear-resistant sterilizing stainless steel composite pipe and preparation method thereof

Abstract

The invention relates to the technical field of composite pipes, and provides a wear-resistant sterilizing stainless steel composite pipe and a preparation method thereof. A wear-resistant sterilizing stainless steel composite pipe sequentially comprises a copper pipe and a stainless steel pipe from inside to outside, and the stainless steel pipe is composed of, by weight, 18%-20% of Cr, 8%-11% of Ni, 0.2%-0.4% of Mo, 1.0%-2.0% of Mn, 0.2%-1.0% of Si, 0.6%-1.0% of Ag, 0.2%-0.8% of Cu, smaller than or equal to 0.1% of N, smaller than or equal to 0.08% of C, smaller than or equal to 0.045% of P, smaller than or equal to 0.03% of S and the balance Fe and inevitable impurities. Wherein the ratio of (Cr + Ni) to (Ag + Cu) is (20-25): 1. By means of the technical scheme, the problem that the stainless steel composite pipe is poor in sterilization performance in the related technology is solved.

Description

Technical Field

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

[0002] In modern industrial and civil fields, the requirements for material performance are becoming more diversified and stringent. A single material is often difficult to meet the complex and changing use requirements. Stainless steel composite pipes came into being. It is not a simple single-material pipe, but a new type of pipe that combines stainless steel with other base materials through a specific process. Stainless steel composite pipes cleverly combine the advantages of stainless steel's strong corrosion resistance, beautiful and hygienic appearance, and the high strength, high wear resistance, and low cost of the base material, achieving an optimal balance between performance and cost. They are widely used in many industries such as building water supply, food processing, and medical equipment. However, as people's attention to health safety and durability continues to increase, the limitations of traditional stainless steel composite pipes in sterilization have gradually become apparent.

[0003] In the food processing industry, pipelines are key components for material transportation, and they are very prone to breeding bacteria. The massive reproduction of bacteria will not only contaminate food raw materials, cause food spoilage, and affect product quality, but may also cause food safety problems and threaten the health of consumers. This is even more true in the medical field. Whether it is the hospital's water supply system or the fluid delivery pipeline in medical equipment, a highly hygienic and sterile environment must be ensured. The breeding of bacteria in the pipeline may cause cross infection and have a serious impact on the patient's treatment and rehabilitation. Therefore, it is necessary to develop a stainless steel composite pipe with bactericidal properties. Summary of the invention

[0004] The invention provides a wear-resistant sterilization stainless steel composite pipe and a preparation method thereof, which solves the problem of poor sterilization performance of the stainless steel composite pipe in the related art.

[0005] The technical solution of the present invention is as follows: The present invention proposes a wear-resistant and sterilizing stainless steel composite tube, which comprises a copper tube and a stainless steel tube from the inside to the outside, and the stainless steel tube is composed of the following components in weight percentage: Cr 18%~20%, Ni 8%~11%, Mo 0.2%~0.4%, Mn 1.0%~2.0%, Si 0.2%~1.0%, Ag 0.6%~1.0%, Cu 0.2%~0.8%, N≤0.1%, C≤0.08%, P≤0.045%, S≤0.03%, and the balance is Fe and unavoidable impurities; wherein (Cr+Ni):(Ag+Cu)=20~25:1.

[0006] The present invention also provides a method for preparing a wear-resistant sterilization stainless steel composite pipe, comprising the following steps: S1, mixing and melting the materials according to the target composition, casting into steel ingots after smelting, rolling into green billets, and obtaining stainless steel plates through solid solution treatment; S2, rolling the stainless steel sheet into a tube, welding and fixing it, grinding and polishing it to obtain a stainless steel tube; S3. Spray the brazing flux on the surface of the steel pipe, insert it into the stainless steel pipe, seal one end, and then evacuate, heat and weld to obtain a wear-resistant and sterilization stainless steel composite pipe.

[0007] As a further technical solution, the melting temperature in S1 is 1720~1760℃, and the smelting temperature is 1600~1620℃.

[0008] As a further technical solution, the rolling temperature in S1 is 1200-1220°C, and the final rolling temperature is 880-900°C.

[0009] As a further technical solution, the temperature of the solution treatment in S1 is 1020~1040°C and the time is 0.6~0.8h.

[0010] As a further technical solution, the vacuum degree of the vacuum pumping in S3 is 1.35×10 -2 Pa.

[0011] As a further technical solution, the sealing welding in S3 is argon arc welding, the welding current is 40A, and the gas flow rate is 15L / min.

[0012] As a further technical solution, the brazing flux in S3 is a copper-silver brazing flux, which is sprayed twice, the contents of copper and silver in the first brazing flux and the second brazing flux are different, and the spraying thickness of the first brazing flux and the second brazing flux is different.

[0013] As a further technical solution, the particle size of the copper-silver brazing flux is 100 μm.

[0014] As a further technical solution, the mass ratio of copper element to silver element in the first brazing flux is 2:8, the mass ratio of copper element to silver element in the second brazing flux is 1:9, the spraying thickness of the first brazing flux is 0.02 mm, and the spraying thickness of the second brazing flux is 0.08 mm.

[0015] In the present invention, the copper content of the first brazing flux is higher than that of the second brazing flux, so that the brazing material can be quickly and evenly spread on the surface of the copper tube to fill the gap and lay the foundation for the welding strength. The silver content of the second brazing flux is relatively high. The second brazing flux is coated on the surface of the first brazing flux and contacts with the stainless steel tube containing the silver element, which significantly improves the overall welding strength of the composite tube and ensures that the copper tube and the stainless steel tube are tightly combined.

[0016] As a further technical solution, the temperature of the heating welding in S3 is 920~980℃.

[0017] As a further technical solution, the material of the copper tube is T1 copper, and the thickness of the copper tube is 0.5 mm.

[0018] The working principle and beneficial effects of the present invention are: In the present invention, the inner layer is made of copper tube and the outer layer is made of stainless steel tube, and the combination of the two forms a structure with complementary advantages. The good thermal conductivity of the copper tube makes the composite tube perform well in heat exchange applications, can quickly conduct heat, and improve heat transfer efficiency; its own corrosion resistance and bactericidal properties ensure the stable operation of the inner layer pipeline and the cleanliness and safety of the fluid in an environment with corrosive media and high hygiene requirements.

[0019] In the present invention, in terms of the composition of the stainless steel pipe, Cr and Ni cooperate to form a dense oxide film, which greatly improves the corrosion resistance and oxidation resistance of the composite pipe, Mo can improve the pitting and crevice corrosion resistance, especially in corrosive media such as chloride ions, which enhances the corrosion resistance of the composite pipe, Mn improves the strength and hardness of the steel, replaces the role of nickel to a certain extent, and reduces the cost, Si forms a dense silicon oxide film at high temperature to protect the steel matrix, and the addition of Ag and Cu gives the composite pipe excellent bactericidal performance, which can effectively inhibit the growth and reproduction of microorganisms such as bacteria and viruses, and meet the needs of industries such as medical and food with extremely high hygiene requirements. At the same time, the contents of N, C, P, and S are strictly controlled to avoid performance degradation caused by impurities, such as intergranular corrosion, cold brittleness, hot brittleness, etc., to ensure the overall performance stability and service life of the composite pipe, and by limiting the proportional relationship between Cr, Ni, Ag and Cu, the synergistic effect between the elements is brought into play to improve the bactericidal performance of the composite pipe. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the following examples and comparative examples: Copper tube: T1 copper tube; The particle size of the solder flux was 100 μm.

[0022] Example 1 The stainless steel pipe is composed of the following components in weight percentage: Cr 18%, Ni 11%, Mo 0.2%, Mn 1.0%, Si0.2%, Ag 0.6%, Cu 0.8%, N 0.05%, C 0.06%, P 0.03%, S 0.02%, and the balance is Fe and unavoidable impurities; A method for preparing a wear-resistant sterilization stainless steel composite pipe comprises the following steps: S1. Mix the materials according to the target composition, heat to 1720°C for melting, smelt at 1600°C and cast into steel ingots, roll at 1200°C, finish roll at 880°C, roll into green billets, and solution treat at 1020°C for 0.8h to obtain stainless steel plates; S2, rolling the stainless steel sheet into a tube, welding, fixing, grinding and polishing to obtain a stainless steel tube; S3. Spray the brazing flux on the surface of the steel pipe, insert the copper pipe into the stainless steel pipe, seal one end with welding, and evacuate to a vacuum degree of 1.35×10 -2 Pa, heated to 920 ° C, and after welding, a wear-resistant and sterilization stainless steel composite pipe was obtained, wherein the sealing welding was argon arc welding, the welding current was 40A, the gas flow rate was 15L / min, the spraying thickness of the brazing flux was 0.1mm, and the brazing flux was composed of copper and silver in a mass ratio of 2:8.

[0023] Example 2 The stainless steel pipe is composed of the following components in weight percentage: Cr 19%, Ni 10%, Mo 0.3%, Mn 1.5%, Si0.5%, Ag 0.8%, Cu 0.5%, N 0.06%, C 0.05%, P 0.04%, S 0.02%, and the balance is Fe and unavoidable impurities; A method for preparing a wear-resistant sterilization stainless steel composite pipe comprises the following steps: S1. Mix the materials according to the target composition, heat to 1740℃ for melting, smelt at 1610℃ and cast into steel ingots, roll at 1210℃, finish roll at 890℃, roll into green billets, and solution treat at 1030℃ for 0.7h to obtain stainless steel plates; S2, rolling the stainless steel sheet into a tube, welding, fixing, grinding and polishing to obtain a stainless steel tube; S3. Spray the brazing flux on the surface of the steel pipe, insert the copper pipe into the stainless steel pipe, seal one end with welding, and evacuate to a vacuum degree of 1.35×10 -2 Pa, heated to 950 ° C, and after welding, a wear-resistant and sterilization stainless steel composite pipe was obtained, wherein the sealing welding was argon arc welding, the welding current was 40A, the gas flow rate was 15L / min, the spraying thickness of the brazing flux was 0.1mm, and the brazing flux was composed of copper and silver in a mass ratio of 2:8.

[0024] Example 3 The stainless steel pipe is composed of the following components in weight percentage: Cr 20%, Ni 8%, Mo 0.4%, Mn 2.0%, Si1.0%, Ag 1.0%, Cu 0.2%, N 0.08%, C 0.07%, P 0.04%, S 0.02%, and the balance is Fe and unavoidable impurities; A method for preparing a wear-resistant sterilization stainless steel composite pipe comprises the following steps: S1. Mix the materials according to the target composition, heat to 1760℃ for melting, smelt at 1620℃ and cast into steel ingots, roll at 1220℃, finish roll at 900℃, roll into green billets, and solution treat at 1040℃ for 0.6h to obtain stainless steel plates; S2, rolling the stainless steel sheet into a tube, welding, fixing, grinding and polishing to obtain a stainless steel tube; S3. Spray the brazing flux on the surface of the steel pipe, insert the copper pipe into the stainless steel pipe, seal one end with welding, and evacuate to a vacuum degree of 1.35×10 -2 Pa, heated to 980 ° C, and after welding, a wear-resistant and sterilization stainless steel composite pipe was obtained, wherein the sealing welding was argon arc welding, the welding current was 40A, the gas flow rate was 15L / min, the spraying thickness of the brazing flux was 0.1mm, and the brazing flux was composed of copper and silver in a mass ratio of 2:8.

[0025] Example 4 Compared with Example 2, the difference in Example 4 is that the mass percentage of Ag in the stainless steel tube is 0.95%.

[0026] Example 5 Compared with Example 2, the difference in Example 5 is that the mass percentage of Ag in the stainless steel tube is 0.66%.

[0027] Example 6 Compared with Example 5, Example 6 is different in that S3 is different. In S3, the first brazing flux is sprayed on the surface of the steel pipe with a spraying thickness of 0.02 mm, and then the second brazing flux is sprayed on the surface of the first brazing flux with a spraying thickness of 0.08 mm. The copper pipe is inserted into the stainless steel pipe, one end is sealed and welded, and then vacuum is evacuated to a vacuum degree of 1.35×10 -2 Pa, heated to 950 ° C, and after welding, a wear-resistant and sterilization stainless steel composite tube was obtained, wherein the first brazing flux consisted of copper and silver in a mass ratio of 2:8, and the second brazing flux consisted of copper and silver in a mass ratio of 1:9.

[0028] Example 7 Compared with Example 6, the difference of Example 7 is that the first brazing flux consists of copper and silver in a mass ratio of 1:9, and the second brazing flux consists of copper and silver in a mass ratio of 2:8.

[0029] Example 8 Compared with Example 6, the difference of Example 8 is that the first brazing flux and the second brazing flux are both composed of copper and silver in a mass ratio of 1:1.

[0030] Example 9 Compared with Example 6, the difference of Example 9 is that the thickness of the first soldering flux spraying is 0.08 mm, and the thickness of the second soldering flux spraying is 0.02 mm.

[0031] Example 10 Compared with Example 6, the difference of Example 10 is that the thickness of the first soldering flux spraying is 0.05 mm, and the thickness of the second soldering flux spraying is 0.05 mm.

[0032] Comparative Example 1 Compared with Example 2, the difference in Comparative Example 1 is that the mass percentage of Ag in the stainless steel tube is 0.50%.

[0033] Comparative Example 2 Compared with Example 2, the difference of Comparative Example 2 is that the mass percentage of Ag in the stainless steel tube is 1.1%.

[0034] Experimental Example 1 The composite pipes prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were tested according to the following method: 1. Antibacterial rate: According to the test method specified in GB / T 42675-2023 "Antibacterial stainless steel welded pipes and fittings", use wet method detection to test the antibacterial properties of the samples.

[0035] 2. Mass wear: According to the test method specified in GB / T 12444-2006 "Metallic material wear test method test ring-test block sliding wear test", the mass wear of the test sample is tested with a pressure of 70N, a rotation speed of 500r / min, and a number of revolutions of 2000r.

[0036] The test results are shown in Table 1: Table 1 Performance test results of the composite pipes prepared in Examples 1 to 5 and Comparative Examples 1 to 2

[0037] Compared with Comparative Examples 1 and 2, the antibacterial rate of Example 2 is higher than that of Comparative Examples 1 and 2, and the mass wear is less than that of Comparative Examples 1 and 2, indicating that when (Cr+Ni):(Ag+Cu)=20~25:1, the bactericidal performance of the composite pipe can be improved.

[0038] Experimental Example 2 The composite pipes prepared in Examples 5 to 10 were tested for their bonding shear strength according to the test method specified in GBT 31940-2015 "Bimetallic Composite Corrosion-Resistant Steel Pipe for Fluid Transportation".

[0039] The test results are shown in Table 2: Table 2 Performance test results of the composite pipes prepared in Examples 5 to 10

[0040] Compared with Example 5, the bonding shear strength of Examples 6 to 10 is higher than that of Example 5, indicating that when the mass ratio of copper element to silver element in the first brazing flux is 2:8, the mass ratio of copper element to silver element in the second brazing flux is 1:9, and the spraying thickness of the first brazing flux is 0.02 mm, and the spraying thickness of the second brazing flux is 0.08 mm, the welding strength of the composite pipe can be improved.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wear-resistant sterilization stainless steel composite pipe, characterized in that: From the inside to the outside, it includes a copper tube and a stainless steel tube, and the stainless steel tube is composed of the following components in weight percentage Composition: Cr 18%~20%, Ni 8%~11%, Mo 0.2%~0.4%, Mn1.0%~2.0%, Si 0.2%~1.0%, Ag 0.6%~1.0%, Cu 0.2%~0.8%, N≤0.1%, C≤0.08%, P≤0.045%, S≤0.03%, the balance is Fe and unavoidable impurities; Among them, (Cr+Ni):(Ag+Cu)=20~25:

1.

2. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 1, characterized in that: The following steps are involved: S1, mixing and melting the materials according to the target composition, casting into steel ingots after smelting, rolling into green billets, and obtaining stainless steel plates through solid solution treatment; S2, rolling the stainless steel sheet into a tube, welding and fixing it, grinding and polishing it to obtain a stainless steel tube; S3. Spray the brazing flux on the surface of the steel pipe, seal one end of the steel pipe, and then evacuate and heat the steel pipe to obtain a wear-resistant and sterilizing stainless steel composite pipe.

3. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The melting temperature in S1 is 1720-1760°C, and the smelting temperature is 1600-1620°C.

4. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The rolling temperature in S1 is 1200-1220°C, and the final rolling temperature is 880-900°C.

5. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The temperature of the solution treatment in S1 is 1020-1040°C, and the time is 0.6-0.8h.

6. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The vacuum degree of the evacuation in S3 is 1.35×10 -2 Pa.

7. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The brazing flux in S3 is a copper-silver brazing flux, which is sprayed twice. The contents of copper and silver elements in the first brazing flux and the second brazing flux are different, and the spraying thicknesses of the first brazing flux and the second brazing flux are different.

8. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 7, characterized in that: The mass ratio of copper element to silver element in the first brazing flux is 2:8, the mass ratio of copper element to silver element in the second brazing flux is 1:9, the spraying thickness of the first brazing flux is 0.02 mm, and the spraying thickness of the second brazing flux is 0.08 mm.

9. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The temperature of the heating welding in S3 is 920-980°C.

10. The method for preparing a wear-resistant sterilization stainless steel composite pipe according to claim 2, characterized in that: The material of the copper tube is T1 copper, and the thickness of the copper tube is 0.5 mm.

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