Microorganism welding process

Abstract

The invention discloses a microorganism welding process which comprises the following steps: S1, selection and culture of microorganisms: selecting microorganisms capable of generating viscous substances or having biomineralization ability, inoculating the selected microorganisms into a culture medium for culture, and after culture is completed, centrifuging and washing to obtain bacterial cells, preparing the bacterial cells into a bacterial suspension; s2, a to-be-welded plate is pretreated; s3, the welding process is conducted, specifically, the surfaces of the pretreated to-be-welded plates are coated with the bacterial suspension, the multiple layers of to-be-welded plates are stacked, pressure is applied, and then microbial metabolic activity is conducted till welding is completed; s4, a post-treatment process is conducted, specifically, the welding part is subjected to heating treatment, microorganisms are removed, and the composite board is obtained; and S5, mechanical property detection is conducted on the welding part, and the welding quality is evaluated. Effective welding between the plates to be welded is achieved by means of metabolic activity of microorganisms and specific substances generated by the microorganisms, and the welding quality and efficiency are improved.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a microbial welding process. Background Art

[0002] Traditional welding processes such as arc welding, gas welding and flame welding are widely used in industrial production, but they also have some limitations. For example, the above welding methods usually require high temperature and high pressure environment, which may cause thermal deformation, compression deformation, and degradation of heat-affected zone performance. In addition, when facing the welding of some special materials or complex structures, traditional welding processes are difficult to achieve large-area, high-quality composite plate connections.

[0003] At present, large-area welding of composite plates mostly adopts explosive welding, which is a welding technology that uses the energy generated by the explosion of explosives to collide two or more metal surfaces at high speed and achieve metallurgical bonding. Although explosive welding has unique advantages in joining dissimilar metals, it also has some disadvantages:

[0004] (1) Since explosives are used as an energy source, explosive welding has high requirements on the operating environment and personnel safety. Specific safety measures are needed to ensure the safety of the operation process, which increases the complexity and cost of the operation.

[0005] (2) During the explosion welding process, the welding quality is affected by many factors, including the type and amount of explosives, explosion speed, gap between plates and environmental conditions. Changes in these factors may lead to unstable quality of the welded joint and make it difficult to accurately control the welding effect.

[0006] (3) Explosive welding is suitable for specific types of materials and shapes. For large-area plates, if the size is too large or the shape is complex, it will become very difficult to implement explosive welding.

[0007] (4) Due to the particularity of its welding principle, explosive welding may not meet the requirements of some applications that require high precision and high-quality surface finish. Especially in cases where high requirements are placed on the appearance and flatness of the joint, explosive welding may result in unsatisfactory results.

[0008] (5) Explosion welding not only causes noise pollution to the surrounding environment, but also may produce harmful substances, causing adverse effects on the environment. Therefore, the application of this technology is limited in densely populated areas or areas with high environmental protection requirements.

[0009] Due to the shortcomings of explosion welding in the process of connecting large panel plates, it is urgent to develop a welding process that can be carried out under mild conditions, has little impact on material properties and has good connection effects. Summary of the invention

[0010] The purpose of the present invention is to provide a microbial welding process to solve the problems of low safety, high technical requirements for workers, low precision and easy deformation of plates caused by the above-mentioned use of explosive welding to connect large-area plates.

[0011] To achieve the above object, the present invention provides a microbial welding process, comprising the following steps:

[0012] S1: Selection and cultivation of microorganisms

[0013] Selecting microorganisms that can produce sticky substances or have biomineralization capabilities, inoculating the selected microorganisms into a culture medium for cultivation, and after the cultivation is completed, obtaining bacterial cells by centrifugation and washing, and configuring the bacterial cells into a bacterial suspension;

[0014] S2: Pretreatment of the plates to be welded

[0015] Clean the surface of the plate to be welded;

[0016] S3: Welding process

[0017] Applying a bacterial suspension to the surface of the pretreated plate to be welded, stacking multiple layers of the plate to be welded, applying pressure, and then carrying out microbial metabolic activities until welding is completed;

[0018] S4: Post-processing

[0019] After welding is completed, the welding part is heated to remove microorganisms and obtain a composite plate;

[0020] S5: Check the welding parts

[0021] Conduct mechanical property tests on composite plates and evaluate welding quality.

[0022] Preferably, in step S1, the microorganism is sulfate-reducing bacteria, and the culture medium is added with 3-6 g Na2SO4, 0.5-1.5 g NH4Cl, 0.5-1.5 g yeast extract powder, 0.5-1.0 g KH2PO4, 0.1-0.5 g sodium citrate, 0.05-0.15 g CaCl2·6H2O, 0.05-0.15 g MgSO4·7H2O, and 0.003-0.008 g FeSO4·7H2O per liter.

[0023] In the process of microbial welding, the cell suspension formed by the microorganisms is coated on the surface of the plate and placed under environmental conditions suitable for the survival of microorganisms. Due to the presence of microorganisms between adjacent plates, local controllable corrosion will occur on the surface of the plate. This corrosion and the metabolites of the microorganisms enable metal-metal bonding to be formed between the plates, achieving close contact at the atomic level, which plays a very important role in improving the connection strength between the plates. When the microorganism is sulfate-reducing bacteria, the metal sulfide produced by the metabolism of sulfate-reducing bacteria can act as a "bridge" between the two metal plates to enhance the bonding strength between them. These sulfides not only fill the tiny gaps that may exist, but also increase the bonding force at the interface. In addition, microbial metabolites may form nano-scale fillers on the surface or in the gaps of the material, similar to a "net-like" structure.

[0024] Preferably, in step S1, the culture conditions are humidity 45-90%, temperature 20-35°C, oxygen content 10-20%, pH 6.5-8.5, and the culture time is 24-72 hours.

[0025] Preferably, in step S1, the inoculation ratio of the microorganisms in the culture medium is 1 / 2000, and 1 g of bacterial cells is added to 500 g of solution to form a bacterial suspension.

[0026] Preferably, in step S2, the pretreatment of the plates to be welded further includes a modification treatment, specifically: using chemical reagents to activate the surfaces of the cleaned plates to be welded.

[0027] Preferably, in step S3, the bacterial suspension is applied by at least one of spraying and brushing, and the application amount is 0.1 to 0.5 L / m 2 .

[0028] Preferably, in step S3, the applied pressure is 3-8 MPa and the welding time is 150-250 h.

[0029] Preferably, in step S3, the conditions for the metabolic activities of the microorganisms are humidity 45-90%, temperature 20-25° C., and oxygen content 10-20%.

[0030] Preferably, in step S4, the heating time is 80-100° C. and the heating time is 1-3 hours.

[0031] Preferably, the plate to be welded is one of metal, non-metal and composite material.

[0032] Therefore, the present invention adopts the above-mentioned microbial welding process, which has the following beneficial effects:

[0033] (1) Traditional welding methods usually require a high temperature environment to melt the metal to achieve connection, which will cause thermal damage to the welding material, causing material deformation or performance degradation. The present invention uses microorganisms to perform welding at room temperature and pressure, and the welding process can be completed without heating to a high temperature, effectively avoiding thermal damage to the material caused by high temperature.

[0034] (2) The industrial process of the present invention is not only applicable to the welding of metal materials, but also can process the connection of various types of materials such as non-metals (such as plastics, ceramics) and composite materials. The selection of microorganisms can be carried out according to the properties of the plate to be treated. The sulfate-reducing bacteria in the present invention react with the surface of the material through its metabolites to form a stable chemical bond. This biomineralization provides a new connection pathway for materials of different properties.

[0035] (3) The microorganisms of the present invention can move in a very small space and produce adhesive substances, so that the plate can be accurately connected to the material at the micrometer or even nanometer level, which is particularly important for achieving high-precision and complex multi-layer structure welding.

[0036] (4) The present invention controls the growth and metabolic activities of microorganisms to ensure that the original size error before welding is controlled within 0.1 mm, which helps to maintain the overall dimensional stability and appearance quality of the welded parts, while improving the quality and sealing of the welded joints.

[0037] (5) The microbial welding process of the present invention does not need to consume a large amount of energy to reach a high temperature state, which significantly reduces the energy demand during the welding process. In addition, due to its relatively mild operating conditions, the cooling time and the consumption of related resources are also reduced. The microorganisms and their metabolites in the present invention are relatively environmentally friendly, reducing the generation of harmful gases or waste. Using microorganisms as welding media can not only reduce environmental pollution, but also help promote the development of green manufacturing technology.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a sulfate-reducing bacteria microbial strain;

[0040] Figure 2 For cell suspension;

[0041] Figure 3 The state of welding for 50 hours in Example 1;

[0042] Figure 4 The state of welding for 90 hours in Example 1;

[0043] Figure 5 The state of Example 1 after welding for 150 hours;

[0044] Figure 6 The state of Example 1 after welding for 170 hours;

[0045] Figure 7 This is the appearance of the composite plate obtained by welding in Example 1;

[0046] Figure 8 This is a SEM image of the composite plate obtained by welding in Example 1;

[0047] Fig. 9 This is a SEM image of the composite plate obtained by welding in Example 2;

[0048] Fig.10 This is a diagram of the mechanical properties of the composite plate obtained by welding Example 1 and Example 2. DETAILED DESCRIPTION

[0049] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and a specific operation process, but the present invention is not limited to this embodiment.

[0050] Example 1

[0051] A microbial welding process comprises the following steps:

[0052] S1: Selection and cultivation of microorganisms

[0053] Select microorganisms that can produce sticky substances or have biomineralization capabilities. In this example, sulfate-reducing bacteria were selected and purchased from Beijing Yita Biotechnology Co., Ltd. The appearance of sulfate-reducing bacteria is as follows: Figure 1 The selected sulfate-reducing bacteria were inoculated into the culture medium for cultivation. The inoculation ratio of the microorganisms in the culture medium was 1 / 2000. The culture medium was added with 4.6 g Na2SO4, 0.9 g NH4Cl, 0.9 g yeast extract powder, 0.7 g KH2PO4, 0.3 g sodium citrate, 0.1 g CaCl2·6H2O, 0.1 g MgSO4·7H2O, and 0.005 g FeSO4·7H2O per liter.

[0054] The culture conditions are humidity 80%, temperature 30°C, oxygen content 15%, pH 7, and shaking culture time 48h. After the culture is completed, the solid matter is obtained by centrifugation, and the bacterial cells are obtained after washing three times with physiological saline. 1 gram of sulfate-reducing bacteria bacterial cells are added to 500 grams of solution to form a bacterial suspension. The bacterial cells are configured into a bacterial suspension. The state of the bacterial suspension is shown in Figure 2 .

[0055] S2: Pretreatment of the plates to be welded

[0056] The plates to be welded are Ti plates and 6061 aluminum plates. The surfaces of the plates to be welded are polished to remove surface oxides and impurities to achieve the purpose of cleaning. The cleaned plates to be welded are immersed in a 15% dilute hydrochloric acid solution for surface activation treatment for 10 minutes. After being taken out, they are rinsed with clean water and dried.

[0057] S3: Welding process

[0058] The microbial suspension was sprayed onto the pretreated Ti plate and 6061 aluminum plate surface with a coating amount of 0.2L / m 2 , the Ti plate and the 6061 aluminum plate with the side coated with the microbial suspension facing each other and stacked, a pressure of 5MPa was applied, and then the microbial metabolic activity was carried out under the conditions of 60% humidity, 25°C temperature and 15% oxygen content. The welding time was 170h until the welding was completed;

[0059] As the welding time increases, different morphologies will appear on the contact surface of the two plates. Figures 3 to 6 .

[0060] S4: Post-processing

[0061] After welding, the welding part is heated at 80°C for 3 hours to remove microorganisms and obtain a composite plate. The appearance of the composite plate is shown in Figure 7 , the microscopic interface of the composite plate is shown in Figure 8 ,from Figure 8 It can be seen that the Ti plate and the 6061 aluminum plate are tightly connected together.

[0062] S5: Check the welding parts

[0063] Conduct mechanical property tests on composite plates and evaluate welding quality.

[0064] Example 2

[0065] A microbial welding process comprises the following steps:

[0066] S1: Selection and cultivation of microorganisms

[0067] Select microorganisms that can produce viscous substances or have biomineralization capabilities. In this embodiment, sulfate-reducing bacteria are selected and purchased from Beijing Ita Biotechnology Co., Ltd. The selected sulfate-reducing bacteria are inoculated into a culture medium for cultivation. The inoculation ratio of the microorganism in the culture medium is 1 / 2000. The culture medium is added with 4.6 g of Na2SO4, 0.9 g of NH4Cl, 0.9 g of yeast extract powder, 0.7 g of KH2PO4, 0.3 g of sodium citrate, 0.1 g of CaCl2·6H2O, 0.1 g of MgSO4·7H2O, and 0.005 g of FeSO4·7H2O per liter.

[0068] The culture conditions are humidity 80%, temperature 25°C, oxygen content 15%, pH 7, and shaking culture time is 48 hours. After the culture is completed, the solid matter is obtained by centrifugation, and the bacterial cells are obtained after washing three times with physiological saline. 1 gram of sulfate-reducing bacteria bacterial cells is added to 500 grams of solution to form a bacterial suspension, and the bacterial cells are configured into a bacterial suspension.

[0069] S2: Pretreatment of the plates to be welded

[0070] The plates to be welded are TiAl plates and Ti2AlNb plates. The surfaces of the plates to be welded are polished to remove surface oxides and impurities to achieve the purpose of cleaning. The cleaned plates to be welded are immersed in a 15% dilute hydrochloric acid solution for surface activation treatment for 10 minutes. After being taken out, they are rinsed with clean water and dried.

[0071] S3: Welding process

[0072] The microbial suspension was sprayed onto the pretreated TiAl plate and Ti2AlNb plate surface with a coating amount of 0.2 L / m 2 The TiAl plate and the Ti2AlNb plate coated with the microbial suspension are stacked opposite each other, and a pressure of 4 MPa is applied. Then, microbial metabolic activities are carried out under the conditions of 60% humidity, 25°C temperature, and 15% oxygen content. The welding time is 210 hours until the welding is completed.

[0073] S4: Post-processing

[0074] After welding, the welding part was heated at 80℃ for 2h to remove microorganisms and obtain a composite plate. The microscopic interface of the composite plate can be seen. Fig. 9 ,from Fig. 9 It can be seen that the TiAl plate and the Ti2AlNb plate are tightly connected together.

[0075] S5: Check the welding parts

[0076] Conduct mechanical property tests on composite plates and evaluate welding quality.

[0077] The mechanical property test results of the composite plates prepared in Example 1 and Example 2 are shown in Table 1, and the specific test process is carried out in accordance with the national standard.

[0078] Table 1 Mechanical properties test results of the composite plates of Example 1 and Example 2

[0079]

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A microbial welding process, characterized in that: The following steps are involved: S1: Selection and cultivation of microorganisms Selecting microorganisms that can produce sticky substances or have biomineralization capabilities, inoculating the selected microorganisms into a culture medium for cultivation, and after the cultivation is completed, obtaining bacterial cells by centrifugation and washing, and configuring the bacterial cells into a bacterial suspension; S2: Pretreatment of the plates to be welded Clean the surface of the plate to be welded; S3: Welding process Applying a bacterial suspension to the surface of the pretreated plate to be welded, stacking multiple layers of the plate to be welded, applying pressure, and then carrying out microbial metabolic activities until welding is completed; S4: Post-processing After welding is completed, the welding part is heated to remove microorganisms and obtain a composite plate; S5: Check the welding parts Conduct mechanical property tests on composite plates and evaluate welding quality.

2. A microbial welding process according to claim 1, characterized in that: In step S1, the microorganism is sulfate-reducing bacteria, and the culture medium is added with 3-6 g Na2SO4, 0.5-1.5 g NH4Cl, 0.5-1.5 g yeast extract powder, 0.5-1.0 g KH2PO4, 0.1-0.5 g sodium citrate, 0.05-0.15 g CaCl2·6H2O, 0.05-0.15 g MgSO4·7H2O, and 0.003-0.008 g FeSO4·7H2O per liter.

3. A microbial welding process according to claim 1, characterized in that: In step S1, the culture conditions are humidity 45-90%, temperature 20-35°C, oxygen content 10-20%, pH 6.5-8.5, and the culture time is 24-72 hours.

4. A microbial welding process according to claim 1, characterized in that: In step S1, the inoculation ratio of the microorganisms in the culture medium is 1 / 2000, and 1 g of bacterial cells is added to 500 g of solution to form a bacterial suspension.

5. A microbial welding process according to claim 1, characterized in that: In step S2, the pretreatment of the plates to be welded also includes a modification treatment, specifically: the cleaned plates to be welded are subjected to surface activation using chemical reagents.

6. A microbial welding process according to claim 1, characterized in that: In step S3, the bacterial suspension is applied by spraying or brushing, and the amount of the applied solution is 0.1 to 0.5 L / m 2 .

7. A microbial welding process according to claim 1, characterized in that: In step S3, the applied pressure is 3-8 MPa and the welding time is 150-250 h.

8. A microbial welding process according to claim 1, characterized in that: In step S3, the conditions for the metabolic activities of the microorganisms are humidity 45-90%, temperature 20-25° C., and oxygen content 10-20%.

9. A microbial welding process according to claim 1, characterized in that: In step S4, the heating time is 80-100° C. and the heating time is 1-3 hours.

10. A microbial welding process according to claim 1, characterized in that: The plate to be welded is one of metal, non-metal and composite material.

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