Multilayer metal composite molded product

Abstract

The invention provides a multi-layer metal composite molded product, the multi-layer metal composite molded product has a multi-layer structure, a bonding layer is arranged between a first layer and a second layer and forms metallurgical bonding with the first layer and the second layer respectively, and the first layer forms interface bonding with the second layer through the bonding layer. By implementing each embodiment of the multi-layer metal composite molded product, the processing difficulty and the manufacturing cost of the multi-layer metal composite molded product can be reduced.

Description

Technical Field

[0001] The present invention belongs to the field of metal composite processing, and particularly relates to a formed product of multi-layer metal composite. Background Art

[0002] In the field of industrial production, especially in production scenarios with strongly corrosive media or harsh environmental conditions such as thermal combustion, chemical engineering, offshore engineering, oil and gas exploitation, etc., production equipment (such as pipelines, reaction kettles, reaction tanks, combustion chambers, etc.) is long-term exposed to composite corrosion factors such as acidic and alkaline media, high salt spray environment or high temperature and high pressure. Traditional single-layer metal structure equipment often suffers from wall thickness reduction, stress cracking and even medium leakage due to surface corrosion, seriously threatening production safety and greatly increasing the equipment replacement frequency.

[0003] For example, in the field of offshore engineering, equipment such as offshore platform jacket and seawater desalination evaporator faces the combined action of multi-phase corrosion in the seawater fully submerged area, splash zone and atmospheric zone. Marine microbial corrosion causes equipment made of carbon steel to form ulcerous corrosion with a depth exceeding 4 mm within 6 months. In the field of oil and gas exploitation, high-acid oil and gas field equipment containing H2S / CO2 needs to bear the dual threats of hydrogen-induced cracking and sulfide stress corrosion cracking. Specifically, in high-pressure gas wells, L80 grade tubing steel undergoes hydrogen embrittlement fracture after 9 months of service, and sand-containing oil and gas flow at a flow rate higher than 15 m / s can cause erosion corrosion of X65 pipeline steel. In the field of chemical production, especially in production systems such as chlor-alkali, chemical fertilizer, sulfuric acid, etc., equipment needs to be in long-term contact with strong corrosive media such as concentrated sulfuric acid with a concentration exceeding 60% and boiling hydrochloric acid, and also faces severe corrosion resistance challenges. For example, the electrolytic cell in the chlor-alkali industry is prone to interfacial hydrogen embrittlement cracking in a 90°C wet chlorine gas environment, and the 316L stainless steel reaction kettle is prone to pitting penetration in a medium containing Cl- ions.

[0004] Although there are solutions such as surface plating or spraying anti-corrosion coatings in the prior art, such single protective layers are prone to local peeling under working conditions such as dynamic scouring and thermal stress alternation, resulting in the exposure of the base material and the spread of pitting corrosion. Although there are also solutions in the prior art to manufacture equipment using a single corrosion-resistant alloy material, this solution has a technical contradiction of excessively high cost and difficulty in balancing mechanical properties and corrosion resistance.

[0005] Compared with the above prior art, if the production equipment is implemented as a formed product of multi-layer metal composite, the manufacturing cost, mechanical properties and corrosion resistance of the production equipment can be further balanced. Compared with the solution of surface plating or spraying anti-corrosion coatings, the mechanical properties and corrosion resistance persistence of the solution using multi-layer metal composite materials are significantly improved; compared with the solution of manufacturing equipment using a single corrosion-resistant alloy material, the manufacturing cost of the solution using multi-layer metal composite materials is significantly reduced.

[0006] In the solution of selecting multi-layer metal composite materials, the formed product of multi-layer metal composite includes at least two layers, namely a base tube layer and a corrosion-resistant layer. The base tube layer is mainly used to provide rigidity, and the corrosion-resistant layer wraps the outer surface of the base tube layer or covers the inner surface of the base tube layer to provide corrosion protection for the base tube layer. If both the inner and outer surfaces of the base tube layer are covered with the corrosion-resistant layer, such a pipe with corrosion treatment on both the inside and outside can cope with harsh working scenarios where there are corrosion factors in both the external environment and internal transmission.

[0007] For the formed product of multi-layer metal composite to meet the requirements of installation, combination, etc., it needs to further perform machining processes such as expanding diameter, bending, flattening, etc. At this time, it is necessary to ensure that the base tube layer and the corrosion-resistant layer do not easily separate and delaminate. Therefore, when manufacturing the formed product of multi-layer metal composite, how to select the composite process of the base tube layer and the corrosion-resistant layer so that the base tube layer and the corrosion-resistant layer have sufficient bonding strength has always been a research hotspot in this field. Further, combined with the selected composite process, to meet the requirements of bonding strength to ensure production efficiency and save materials to reduce manufacturing costs at a predetermined yield rate, how to select the thickness of each layer and the proportional relationship between the thicknesses of each layer is also a technical difficulty in this field. Summary of the Invention

[0008] In order to overcome the above-mentioned defects in the prior art, the present invention provides a formed product of multi-layer metal composite, which includes a first layer, a second layer and a bonding layer, wherein:

[0009] The first layer has a first surface facing the second layer, and the material of the first layer is a first alloy;

[0010] The second layer has a second surface facing the first layer, and the second layer conformally covers the first surface, and the material of the second layer is a second alloy;

[0011] The bonding layer is disposed between the first surface and the second surface and forms a metallurgical bond with the first surface and the second surface respectively. The material of the bonding layer is a third alloy, and the melting point of the third alloy is lower than the melting points of the first alloy and the second alloy;

[0012] The first layer forms an interfacial bond with the second layer through the bonding layer, and the separation strength between the first layer and the second layer is not less than 137 MPa;

[0013] The thickness range of the bonding layer is from 0.01 mm to 0.5 mm, and the thicknesses of the first layer and the second layer are at least twice the thickness of the bonding layer.

[0014] According to one aspect of the present invention, the formed product has an inner cavity; the inner cavity is formed by the extension and enclosure of the first layer or the second layer.

[0015] According to another aspect of the present invention, the formed product is a metal composite pipe; the first layer extends and encloses to form the base pipe of the metal composite pipe; the second layer extends and encloses to form the inner liner pipe of the metal composite pipe; the inner wall of the inner liner pipe encloses to form the inner cavity.

[0016] According to another aspect of the present invention, in the formed product, the thickness of the first layer is 6 to 2000 times the thickness of the bonding layer; the thickness of the second layer is 2 to 300 times the thickness of the bonding layer.

[0017] According to another aspect of the present invention, in the formed product, the ratio of the melting point of the third alloy to the melting point of the first alloy is 0.55 to 0.715; the ratio of the melting point of the third alloy to the melting point of the second alloy is 0.586 to 0.853.

[0018] According to another aspect of the present invention, in the formed product, the first alloy includes any one or all of carbon steel and iron-based alloys; the second alloy includes any one, any combination or all of alloy steel, 316L stainless steel, nickel-based alloys, cobalt-based alloys and titanium alloys; the third alloy includes any one, any combination or all of nickel-based alloys, cobalt-based alloys and iron-based alloys doped with boron and / or silicon.

[0019] According to another aspect of the present invention, the formed product is a metal composite pipe; the first layer extends and encloses to form the outer sleeve pipe of the metal composite pipe; the second layer extends and encloses to form the base pipe of the metal composite pipe; the inner wall of the base pipe encloses to form the inner cavity.

[0020] According to another aspect of the present invention, in the formed product, the thickness of the first layer is 2 to 300 times the thickness of the bonding layer; the thickness of the second layer is 6 to 2000 times the thickness of the bonding layer.

[0021] According to another aspect of the present invention, in the formed product, the ratio of the melting point of the third alloy to the melting point of the second alloy is 0.55 to 0.715; the ratio of the melting point of the third alloy to the melting point of the first alloy is 0.586 to 0.853.

[0022] According to another aspect of the present invention, in the formed product, the first alloy includes any one, any combination or all of alloy steel, 316L stainless steel, nickel-based alloy, cobalt-based alloy and titanium alloy; the second alloy includes any one or all of carbon steel and iron-based alloy; the third alloy includes any one, any combination or all of nickel-based alloy, cobalt-based alloy and iron-based alloy doped with boron and / or silicon.

[0023] According to another aspect of the present invention, in the formed product, the radial cross-sectional shape of the metal composite pipe is circular, rectangular, regular polygon or irregular polygon; the first layer, the second layer and the bonding layer all have a substantially uniform thickness.

[0024] According to another aspect of the present invention, in the formed product, the porosity of the bonding layer does not exceed 5%; the separation strength between the first layer and the second layer is greater than 300 Mpa.

[0025] The formed product provided by the present invention with a multi-layer metal composite has a multi-layer structure. The bonding layer is arranged between the first layer and the second layer and forms a metallurgical bond with the first layer and the second layer respectively. The first layer forms an interfacial bond with the second layer through the bonding layer. Due to the high strength of the metallurgical bond, the first layer and the second layer have sufficient bonding strength and are not easily separated even during subsequent machining; the thickness range of the bonding layer is set to 0.01 mm to 0.5 mm, which can effectively save materials on the premise of ensuring the metallurgical bond strength and reduce the manufacturing cost of the formed product with the multi-layer metal composite; further, the thicknesses of the first layer and the second layer are set to be at least twice the thickness of the bonding layer, which is convenient for controlling the diffusion uniformity of the bonding layer during heat treatment and also avoids excessive diffusion of the components of the bonding layer into the first layer and the second layer during the formation of the metallurgical bond, and the excessive diffusion will affect the performance of the first layer and the second layer themselves. Description of the Drawings

[0026] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become more apparent:

[0027] Figure 1A is a schematic cross-sectional structure view of a specific embodiment of the formed product with a multi-layer metal composite according to the present invention;

[0028] Figure 1B is Figure 1A a disassembled schematic view of the shown specific embodiment;

[0029] Figure 2 is a schematic cross-sectional structure view of another specific embodiment of the formed product with a multi-layer metal composite according to the present invention;

[0030] Figure 3A is a schematic cross-sectional structure diagram of another specific embodiment of the formed product with multi-layer metal composite according to the present invention;

[0031] Figure 3B is Figure 3A a real-shot cross-sectional structure diagram of the specific embodiment shown;

[0032] Figure 3C is Figure 3B a metallographic magnification diagram of the specific embodiment shown;

[0033] Figure 3D is for Figure 3B a real-shot diagram after the flattening test of the specific embodiment shown;

[0034] Figure 4 is a schematic cross-sectional structure diagram of another specific embodiment of the formed product with multi-layer metal composite according to the present invention;

[0035] Figure 5 is a schematic cross-sectional structure diagram of another specific embodiment of the formed product with multi-layer metal composite according to the present invention;

[0036] The same or similar reference numerals in the drawings represent the same or similar components. Specific Embodiment

[0037] For a better understanding and interpretation of the present invention, the present invention will be further described in detail below with reference to the drawings. The present invention is not limited solely to these specific embodiments. On the contrary, modifications or equivalent substitutions made to the present invention shall be covered within the scope of the claims of the present invention.

[0038] It should be noted that numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present invention can still be implemented without these specific details. In the multiple specific embodiments given below, well-known structures and components are not described in detail in order to highlight the gist of the present invention.

[0039] In the description of the following specific embodiments, the orientation or positional relationships such as "upper", "lower", etc. are based on the orientation or positional relationships shown in the drawings, and are only for convenience of description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive distinction and have no special meaning.

[0040] The following will describe the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification. It should be noted that each accompanying drawing of the specification is only used to schematically illustrate the technical solution and core concept of the present invention. The shapes and sizes of the components of each specific embodiment shown in the accompanying drawings are not drawn strictly in accordance with the shape of the actual product. There may be differences between the shape, size ratio of the actual product and the specific embodiments shown in the accompanying drawings of the specification. Therefore, the specific embodiments shown in the drawings should not be construed as the only limitation on the corresponding actual product of the present invention, nor can it be used as the sole basis for comparing shapes and sizes in determining patent infringement acts.

[0041] First, please refer to Figure 1A and Figure 1B , Figure 1A which is a schematic cross-sectional structure diagram of a specific embodiment of a multi-layer metal composite formed product according to the present invention. More specifically, Figure 1A the part shown is a local section intercepted from a continuous multi-layer metal composite formed product, and is only used to illustrate the relative positional relationship of each layer in the multi-layer metal composite formed product.

[0042] As Figure 1A shown, the multi-layer metal composite formed product 10 includes a first layer 110, a second layer 120, and a bonding layer 130. The first layer 110 forms an interfacial bond with the second layer 120 through the bonding layer 130. Figure 1B is Figure 1A a disassembled schematic diagram of the specific embodiment shown. As Figure 1B shown, the first layer 110 has a first surface 111 facing the second layer 120. The second layer 120 has a second surface 121 facing the first layer 110, and the second layer 120 conformally covers the first surface 111. The bonding layer 130 is disposed between the first surface 111 and the second surface 121, and forms a metallurgical bond with the first surface 111 and the second surface 121 respectively. In this specific embodiment or other specific embodiments, the first surface 111 can be defined as the metallurgical bonding interface between the first layer 110 and the bonding layer 130, and the second surface 121 can be defined as the metallurgical bonding interface between the second layer 120 and the bonding layer 130. This definition can be extended to the description of other specific embodiments hereinafter. The first surface 111 and the second surface 121 are generally difficult to observe with the naked eye, but the first surface 111 and the second surface 121 can usually be defined by means of metallographic microscopy.

[0043] Since the formed product 10 of multi-layer metal composite has the requirement of subsequent machining, the first layer 110 and the second layer 120 need to have sufficient bonding strength, and metallurgical bonding is undoubtedly a bonding method with the greatest bonding strength at present. In this specific embodiment, the bonding layer 130 forms metallurgical bonds with the first surface 111 and the second surface 121 respectively, which also enables the first layer 110 and the second layer 120 to form an interfacial bond in the form of metallurgical bonding. Correspondingly, the materials selected for the first layer 110, the second layer 120, and the bonding layer 130 should be metals. The material of the first layer 110 is the first alloy, the material of the second layer 120 is the second alloy, and the material of the bonding layer 130 is the third alloy. This bonding method enables the first layer 110 and the second layer 120 to have a high bonding strength, and the separation strength between the first layer 110 and the second layer 120 is not less than 137 Mpa.

[0044] Those skilled in the art can understand that to form the above-mentioned metallurgical bond, it is necessary to perform remelting heat treatment on the bonding layer 130. By raising the temperature of the bonding layer 130, atomic diffusion is formed between the bonding layer 130 and the first layer 110 at the first surface 111, and atomic diffusion is formed between the bonding layer 130 and the second layer 120 at the second surface 121, so as to achieve the metallurgical bond between the bonding layer 130 and the first layer 110 and the second layer 120 respectively. In the actual manufacturing process, first, the first layer 110, the bonding layer 130, and the second layer 120 are arranged as Figure 1AStacked in the order shown and applying appropriate pressure from the outside, the bonding layer 130 is completely covered by the first layer 110 and the second layer 120 at this time. Subsequently, a suitable heating method is selected to continuously increase the temperature of the bonding layer 130 until it reaches the melting point of the bonding layer 130. Whether the heat source is set outside the first layer 110 or the second layer 120, or heat sources are set outside both the first layer 110 and the second layer 120, the heat cannot be directly transferred to the bonding layer 130, but is transferred to the bonding layer 130 through the first layer 110 or the second layer 120. Therefore, the multi-layer metal composite formed product 10 is heated as a whole during the manufacturing process, and the bonding layer 130 cannot be heated separately. Ideally, during the process of the bonding layer 130 forming metallurgical bonds with the first layer 110 and the second layer 120 respectively, the self-strength, surface properties, etc. of the first layer 110 and the second layer 120 will not be damaged. Based on this consideration, that is, when it is desired that the temperature of the bonding layer 130 is heated to its melting point, the temperatures of the first layer 110 and the second layer 120 have not reached their corresponding melting points. Therefore, the melting point of the third alloy is selectively set to be lower than the melting points of the first alloy and the second alloy. If the melting point of the third alloy is greater than the melting points of the first alloy and the second alloy, before the bonding layer 130 forms metallurgical bonds with the first layer 110 and the second layer 120, the first layer 110 and the second layer 120 will be melted, and during the subsequent re-cooling process, the first layer 110 and the second layer 120 may become embrittled, resulting in cracks, and there may also be adverse effects such as pores, coarse grains, and stress accumulation inside, thereby causing the first layer 110 and the second layer 120 to lose their toughness and strength.

[0045] Obviously, only when the melting point of the third alloy is selectively set to be lower than the melting points of the first alloy and the second alloy, can the structure of the multi-layer metal composite formed product 10 shown in Figure 1A be stably and qualifiedly formed.

[0046] In most cases, considering the manufacturing cost of the formed product 10 based on multi-layer metal composite, the first layer 110 and the second layer 120 are usually made of different materials. At this time, the first alloy and the second alloy are different types of metal alloys. For example, the first layer 110 is formed by using the first alloy with lower cost, which is mainly used to provide the mechanical properties of the formed product 10 of multi-layer metal composite to resist tensile force, pressure, impact force, etc. applied inside and outside the formed product 10 of multi-layer metal composite. The second layer 120 is formed by using the second alloy with higher cost, which is mainly used to enhance the corrosion resistance of the formed product 10 of multi-layer metal composite to resist chemical corrosion, impact corrosion, etc. inside or outside the formed product 10 of multi-layer metal composite. Of course, the functions of the first layer 110 and the second layer 120 can also be interchanged, which depends on the working scenario of the formed product 10 of multi-layer metal composite, that is, depends on whether the acting factor causing corrosion to the formed product 10 of multi-layer metal composite comes from the external space of the first layer 110 or the external space of the second layer 120.

[0047] In some special cases, the formed product 10 of multi-layer metal composite works in a position or environment where it is difficult to carry out post-maintenance, or there are high-corrosion environments both inside and outside the formed product 10 of multi-layer metal composite. To deal with these special cases, the cost is often ignored and the corrosion resistance of the formed product 10 of multi-layer metal composite is strengthened as much as possible. Therefore, the first layer 110 and the second layer 120 can be made of the same material. At this time, the first alloy and the second alloy can be selected as the same metal alloy with higher cost, or can be selected as two metal alloys with higher cost.

[0048] Of course, no matter how the materials of the first alloy and the second alloy are selected, the prerequisite that the melting point of the third alloy is lower than the melting points of the first alloy and the second alloy should be satisfied. Adjusting the melting point of the third alloy can be achieved by adding metalloid dopants to the alloy material, such as adding boron element or silicon element.

[0049] On this basis, through repeated experiments for verification, when the thickness of the bonding layer 130 is greater than 0.01 mm, it can meet the requirement that the bonding layer 130 can firmly and controllably form a metallurgical bond with the first layer 110 and the second layer 120 respectively. Eventually, the first layer 110 forms a metallurgical bond with sufficient strength through the bonding layer 130 and the second layer 120. Considering material saving, the maximum thickness of the bonding layer 130 can be set to 0.5 mm. Therefore, the thickness of the bonding layer 130 can be selected within the range of 0.01 mm to 0.5 mm. At the same time, further experimental verification shows that when the thicknesses of the first layer 110 and the second layer 120 are set to be at least twice the thickness of the bonding layer 130, due to the sufficient thicknesses of the first layer 110 and the second layer 120, even if there are slight deviations in temperature control or heating duration during the remelting process of the bonding layer 130, it is not easy for the components of the bonding layer 130 to diffuse excessively into the first layer 110 and the second layer 120. The excessive diffusion may cause the overall or local element ratio imbalance, metallographic deterioration, etc. of the first layer 110 and the second layer 120. For example, the diffusion of boron or silicon may lead to grain boundary brittleness or element segregation, thereby degrading the overall performance of the first layer 110 and the second layer 120.

[0050] In addition, when the thickness of the bonding layer 130 is selected to fall within the range of 0.01 mm to 0.5 mm, the bonding layer 130 has the characteristics of easy heating and melting that thin-layer metals naturally have, thereby reducing the probability of porosity generation during cooling after uneven melting of the bonding layer 130. Moreover, the elastic deformation of the thin-layer metal can also offset part of the internal stress, making the metallurgical bond between the bonding layer 130 and the first layer 110 and the second layer 120 tighter. Typically, the porosity of the bonding layer 130 does not exceed 5%, and the separation strength between the first layer 110 and the second layer 120 is greater than 300 Mpa.

[0051] Figure 1A In the illustrated embodiment, the first layer 110, the second layer 120, and the bonding layer 130 in the multi-layer metal composite formed product 10 all present a flat shape. In more embodiments, according to the functions corresponding to the multi-layer metal composite formed product, the multi-layer metal composite formed product can be implemented in other shapes. Please refer to Figure 2 , Figure 2 is a schematic cross-sectional structure view of another specific embodiment of the multi-layer metal composite formed product according to the present invention. Similarly to the Figure 1A illustrated embodiment, the multi-layer metal composite formed product 20 has a first layer 210, a second layer 220, and a bonding layer 230 with an arc-shaped cross-section. The bonding layer 230 forms a metallurgical bond with the first layer 210 and the second layer 220 respectively. Figure 2The shown multi-layer metal composite formed product 20 can be used in the production of chemical products. A cavity formed by the second layer 220 contains corrosive liquid for participating in chemical reactions. Correspondingly, the material of the second layer 220, i.e., the second alloy, should be selected as a corrosion-resistant alloy.

[0052] In most application scenarios, the multi-layer metal composite formed product of the present invention often has an inner cavity, which is formed by the extension and enclosure of the first layer or the second layer. A typical embodiment is that the multi-layer metal composite formed product is a metal composite pipe. Please refer to Figure 3A , Figure 3A FIG. is a schematic cross-sectional structure view of another specific embodiment of the multi-layer metal composite formed product according to the present invention. In Figure 3A the shown specific embodiment, the multi-layer metal composite formed product is a metal composite pipe 30, which has a first layer 310, a second layer 320, and a bonding layer 330. The bonding layer 330 forms a metallurgical bond with the first layer 310 and the second layer 320 respectively, so that the first layer 310 forms an interfacial bond with the second layer 320 through the bonding layer 330. The first layer 310 extends and encloses to form the base pipe of the metal composite pipe 30, and the second layer 320 extends and encloses to form the inner liner pipe of the metal composite pipe 30. The inner wall of the inner liner pipe encloses to form an inner cavity 340. A typical application scenario of this metal composite pipe 30 is for the closed transportation of high-temperature flue gas discharge, oil and gas transportation, and strong oxidizing medium transportation. In these application scenarios, the inner cavity 340 is filled with highly corrosive media (such as flue gas or combustible gas containing particulate matter, petroleum crude oil, strong oxidizing wet chlorine gas, etc.). Therefore, the corrosion source of the metal composite pipe 30 mainly exists in its inner cavity 340.

[0053] Correspondingly, the first alloy constituting the first layer 310 can be selected from alloys with lower costs. Typically, the first alloy includes any one or all of carbon steel and iron-based alloys; the second alloy constituting the second layer 320 needs to have sufficient corrosion resistance, so alloys with higher costs should be selected. Typically, the second alloy includes any one, any combination, or all of alloy steel, 316L stainless steel, nickel-based alloys, cobalt-based alloys, and titanium alloys. The third alloy constituting the bonding layer 330 should have a melting point lower than that of the first alloy and the second alloy. Typically, the third alloy includes any one, any combination, or all of nickel-based alloys, cobalt-based alloys, and iron-based alloys doped with boron and / or silicon. Those skilled in the art know that doping boron elements and / or silicon elements into nickel-based / cobalt-based / iron-based alloys can effectively reduce the melting point of nickel-based / cobalt-based / iron-based alloys, and controlling the doping amount of boron elements and / or silicon elements can adjust the temperature difference between the melting point of the third alloy and the melting points of the first alloy and the second alloy.

[0054] When manufacturing the metal composite pipe 30, the commonly used method is to spray a layer of the third alloy on the outer surface of the inner liner pipe formed by the second layer 320 to form a bonding layer 330, and then press-fit the inner liner pipe into the base pipe formed by the first layer 310. Further heat treatment is performed on the multi-layer pipe nested with the base pipe, the bonding layer 330, and the inner liner pipe, so that the bonding layer 330 is remelted and metallurgically bonded to the first layer 310 and the second layer 320 respectively. According to the specific compositions of the first alloy, the second alloy, and the third alloy listed in this specific embodiment, the melting point of the first alloy is the same as or close to the melting point of iron, that is, not higher than 1538 °C. The melting point of the second alloy generally falls within the range of 1290 °C to 1450 °C. The melting point of the third alloy is preferably adjusted to fall within the range of 850 °C to 1100 °C. Therefore, preferably in this specific embodiment, the ratio of the melting point of the third alloy to the melting point of the first alloy is 0.55 to 0.715, and the ratio of the melting point of the third alloy to the melting point of the second alloy is 0.586 to 0.853. The selection of the melting points of the above layers is beneficial to improving the yield rate when manufacturing the metal composite pipe 30.

[0055] The implementer of this specific embodiment can select the material of the second alloy according to the type of corrosive medium in the inner cavity 340. For example, austenitic stainless steel (such as 316L stainless steel) is selected to deal with the case of salt spray corrosion, duplex stainless steel is selected to deal with the cases of erosion corrosion and chloride ion corrosion, Hastelloy in nickel-based alloys is selected to deal with the cases of high-temperature flue gas corrosion, acidic gas corrosion, and boiling strong acid, TA2 titanium alloy is selected to deal with the cases of brine corrosion and chloride ion stress corrosion, and cobalt-based alloy Stellite is selected to deal with the cases where chemical corrosion type and erosion-corrosion type coexist, etc. Therefore, the material selection of the second alloy is highly related to the working scenario of the metal composite pipe 30 and can be flexibly selected according to the actual situation. The present invention does not limit this.

[0056] With Figure 1ASimilar to the specific embodiments shown, in the metal composite pipe 30 of this specific embodiment, the thickness range of the bonding layer 330 is from 0.01 mm to 0.5 mm, and the thickness of the first layer 310 and the second layer 320 is at least twice the thickness of the bonding layer 330. More typically, since the first layer 310 is used to form the base pipe of the metal composite pipe 30, and the strength of the base pipe is positively correlated with the strength of the metal composite pipe 30, it is preferably that the thickness range of the first layer 310 is from 3 mm to 20 mm; the second layer 320 forms the lining pipe of the metal composite pipe 30, and the thickness of the lining pipe is positively correlated with the corrosion resistance of the metal composite pipe 30. At the same time, the economy of manufacturing cost should be considered. Therefore, it is preferably that the thickness range of the second layer 320 is from 1 mm to 3 mm. Based on the selection of the thickness ranges of the above layers, preferably in this specific embodiment, the thickness of the first layer 310 is 6 to 2000 times the thickness of the bonding layer 330, and the thickness of the second layer 320 is 2 to 300 times the thickness of the bonding layer 330.

[0057] Similar to Figure 1A the specific embodiment shown, in this specific embodiment, when the thicknesses of the first layer 330, the second layer 320, and the bonding layer 330 meet the values defined above, the porosity of the bonding layer 330 does not exceed 5%, and the separation strength between the first layer 310 and the second layer 320 is greater than 300 Mpa.

[0058] Please refer to Figure 3B , Figure 3B which Figure 3A is the actual cross-sectional structure picture of the specific embodiment shown. In Figure 3B the metal composite pipe 30 shown, the thickness of the first layer 310 is about 10 mm, the thickness of the second layer 320 is about 2 mm, and the thickness of the bonding layer 330 is about 0.1 mm. Moreover, the first layer 310, the second layer 320, and the bonding layer 330 all have a substantially uniform thickness. This thickness consistency is also beneficial to improving the yield rate of the metal composite pipe 30 during manufacturing.

[0059] Please refer to Figure 3C , Figure 3C which Figure 3B is the metallographic magnification picture of the specific embodiment shown. More specifically, Figure 3C the metallographic structure shown Figure 3B is the metallographic state presented after the first layer 310 forms an interfacial bond with the second layer 320 through the bonding layer 330 in the metal composite pipe 30 shown. It can be seen that the bonding layer 330 forms a dense metallurgical bond with both the first layer 310 and the second layer 320 at the same time, which gives sufficient bonding strength between the first layer 310 and the second layer 320. This bonding strength can approach the shear strength of the first layer 310 and the second layer 320, and can reach up to about 450 Mpa at most.

[0060] right Figure 3B The flattening test performed on the metal composite pipe 30 also shows that the first layer 310 and the second layer 320 have a sufficiently high bonding strength. Even if a huge shear stress is generated due to deformation, the first layer 310 and the second layer 320 will not delaminate. Figure 3D , Figure 3D Yes Figure 3B The specific embodiment shown in the figure is subjected to a flattening test, and radial pressure is applied to the metal composite pipe 30 to deform it to the following Figure 3D After the state shown, the first layer 310 and the second layer 320 can still maintain interface bonding.

[0061] As mentioned above, a typical embodiment of the multi-layer metal composite formed product according to the present invention is implemented as a metal composite pipe, but it is obvious that the metal composite pipe is not limited to Figure 3B The structure provided by the specific implementation method is Figure 3B In the specific implementation of the invention, the function of the second layer 320 is defined as a corrosion-resistant layer, which is used to transport corrosive media, that is, the corrosion source mainly exists in the inner cavity 340 of the metal composite pipe 30. In other application scenarios, the metal composite pipe needs to deal with the situation where there is a corrosion source in its installation environment, that is, the corrosion source comes from the outside of the metal composite pipe. For these application scenarios, it is obviously necessary to consider corrosion-resistant treatment of the outer layer of the metal composite pipe. Please refer to Figure 4 , Figure 4 FIG. 1 is a schematic cross-sectional view of another specific embodiment of the multi-layer metal composite molded product according to the present invention. Figure 4 The metal composite pipe 40 shown has a first layer 410, a second layer 420 and a bonding layer 430, and the bonding layer 430 forms a metallurgical bond with the first layer 410 and the second layer 420 respectively, so that the first layer 410 forms an interface bond with the second layer 420 through the bonding layer 430. Among them, the first layer 410 extends to enclose the outer sleeve of the metal composite pipe 40, and the second layer 420 extends to enclose the base pipe of the metal composite pipe 40, and the inner wall of the base pipe encloses to form an inner cavity. The role of the outer sleeve is to provide a corrosion-resistant layer on the outside of the base pipe. Therefore, the typical application scenario of the metal composite pipe 40 is to transport weakly corrosive media in a closed manner under working conditions where there are many corrosive factors in the external environment. For example, the metal composite pipe 40 is used to construct deep-sea oil and gas pipelines, underwater cooling pipes, fluidized bed walls, waste incineration combustion chamber walls, etc.

[0062] Accordingly, in this specific embodiment, the first alloy constituting the first layer 410 needs to have sufficient corrosion resistance, and alloys with relatively high costs can be selected. Typically, the first alloy includes any one, any combination, or all of alloy steel, 316L stainless steel, nickel-based alloys, cobalt-based alloys, and titanium alloys; the second alloy constituting the second layer 420 can be an alloy with a relatively low cost. Typically, the second alloy includes any one or all of carbon steel and iron-based alloys; the third alloy constituting the bonding layer 430 should have a melting point lower than that of the first alloy and the second alloy. Typically, the third alloy includes any one, any combination, or all of nickel-based alloys, cobalt-based alloys, and iron-based alloys doped with boron and / or silicon. According to the specific compositions of the first alloy, the second alloy, and the third alloy listed in this specific embodiment, the melting point of the second alloy is the same as or close to the melting point of elemental iron, that is, not higher than 1538 °C. The melting point of the first alloy generally falls within the range of 1290 °C to 1450 °C, and the melting point of the third alloy is preferably adjusted to fall within the range of 850 °C to 1100 °C. Therefore, preferably in this specific embodiment, the ratio of the melting point of the third alloy to the melting point of the second alloy is 0.55 to 0.715; the ratio of the melting point of the third alloy to the melting point of the first alloy is 0.586 to 0.853. The selection of the melting points of the above layers is beneficial to improving the yield rate of the metal composite pipe 40 during manufacturing.

[0063] The implementer of this specific embodiment can select the material of the first alloy according to the working environment of the metal composite pipe 40. The material selection of the first alloy is related to the corrosion factors in the working environment of the metal composite pipe 40 and can be flexibly selected according to the actual situation. The present invention does not limit this.

[0064] In the metal composite pipe 40 of this specific embodiment, the thickness range of the bonding layer 430 is 0.01 mm to 0.5 mm. The first layer 410 is used as a corrosion-resistant layer, and its thickness range is 1 mm to 3 mm. Therefore, the thickness of the first layer 410 is 2 to 300 times the thickness of the bonding layer 430. The second layer 420 is used to form the base pipe of the metal composite pipe 40, and its thickness range is 3 mm to 20 mm. Therefore, the thickness of the second layer 420 is 6 to 2000 times the thickness of the bonding layer 430. Based on the selection of the thickness ranges of the above layers, the manufacturing cost, corrosion resistance, and yield rate of the metal composite pipe 40 can all reach the expected values. The porosity of the bonding layer 430 does not exceed 5%, and the separation strength between the first layer 410 and the second layer 420 is greater than 300 Mpa. Preferably, the first layer 410, the second layer 420, and the bonding layer 430 all have a substantially uniform thickness, and this thickness consistency is also beneficial to improving the yield rate of the metal composite pipe 40 during manufacturing.

[0065] Figure 3A andFigure 4 In the two specific embodiments of the metal composite pipe shown, the metal composite pipe is implemented as a common cylindrical pipe, so its radial cross-sectional shape is a circle. In more specific embodiments, the metal composite pipe can be implemented in other shapes, and its radial cross-sectional shape is a rectangle, a regular polygon or an irregular polygon accordingly. Please refer to Figure 5 , Figure 5 1 is a schematic cross-sectional view of another specific embodiment of a multi-layer metal composite molded product according to the present invention. Specifically, the multi-layer metal composite molded product in this specific embodiment is a square tube 50, which has a first layer 510, a second layer 520 and a bonding layer 530. The bonding layer 530 forms a metallurgical bond with the first layer 510 and the second layer 520 respectively, so that the first layer 510 forms an interface bond with the second layer 520 through the bonding layer 530. Figure 3A The only difference of the specific embodiment shown is that the cross-sectional shape of the square tube 50 is a polygonal shape that is approximately rectangular, and the first layer 510, the second layer 520 and the bonding layer 530 can refer to the above description of Figure 3A For the description of the specific implementation method, please refer to the above Figure 4 The specific implementation method of the present invention will not be described here for the sake of brevity.

[0066] It is obvious 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and all changes within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other parts, units or steps, and the singular does not exclude the plural.

[0067] The formed product with multi-layer metal composite provided by the present invention has a multi-layer structure. A bonding layer is disposed between a first layer and a second layer and forms a metallurgical bond with the first layer and the second layer respectively. The first layer forms an interfacial bond with the second layer through the bonding layer. Due to the very high strength of the metallurgical bond, the first layer and the second layer have sufficient bonding strength and are not easily separated even during subsequent machining. The thickness range of the bonding layer is set to be from 0.01 mm to 0.5 mm, which can effectively save materials on the premise of ensuring the metallurgical bond strength and reduce the manufacturing cost of the formed product with multi-layer metal composite. Further, the thicknesses of the first layer and the second layer are set to be at least twice the thickness of the bonding layer, which is convenient for controlling the uniformity of diffusion of the bonding layer during heat treatment and also avoids excessive diffusion of the components of the bonding layer into the first layer and the second layer during the formation of the metallurgical bond, and the excessive diffusion will affect the performance of the first layer and the second layer themselves.

[0068] The above-disclosed are only some preferred embodiments of the present invention, and the scope of rights of the present invention cannot be limited thereby. Equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A multi-layer metal composite molded product, the molded product comprising a first layer, a second layer and a bonding layer, wherein: The first layer has a first surface facing the second layer, and the material of the first layer is a first alloy; The second layer has a second surface facing the first layer, the second layer conformally covers the first surface, and the material of the second layer is a second alloy; The bonding layer is disposed between the first surface and the second surface and forms a metallurgical bond with the first surface and the second surface respectively. The material of the bonding layer is a third alloy, and the melting point of the third alloy is lower than the melting points of the first alloy and the second alloy. The first layer is interfacially bonded to the second layer through the bonding layer, and the separation strength between the first layer and the second layer is not less than 137 MPa; The thickness of the bonding layer ranges from 0.01 mm to 0.5 mm, and the thickness of the first layer and the thickness of the second layer are at least twice the thickness of the bonding layer.

2. The molded product according to claim 1, wherein: The molded product has an inner cavity; The inner cavity is formed by extending and enclosing the first layer or the second layer.

3. The molded product according to claim 2, wherein: The molded product is a metal composite pipe; The first layer extends to enclose and form a base pipe of the metal composite pipe; The second layer extends to enclose and form an inner liner of the metal composite pipe; The inner wall of the liner tube encloses and forms the inner cavity.

4. The shaped product according to claim 3, wherein: The thickness of the first layer is 6 to 2000 times the thickness of the bonding layer; The thickness of the second layer is 2 to 300 times the thickness of the bonding layer.

5. The shaped product according to claim 3, wherein: The ratio of the melting point of the third alloy to the melting point of the first alloy is 0.55 to 0.715; The ratio of the melting point of the third alloy to the melting point of the second alloy is 0.586 to 0.

853.

6. The shaped product according to claim 5, wherein: The first alloy includes any one or all of carbon steel and iron-based alloy; The second alloy includes any one, any combination or all of alloy steel, 316L stainless steel, nickel-based alloy, cobalt-based alloy and titanium alloy; The third alloy includes any one, any combination or all of a nickel-based alloy, a cobalt-based alloy and an iron-based alloy doped with boron and / or silicon.

7. The shaped product according to claim 2, wherein: The molded product is a metal composite pipe; The first layer extends to enclose and form an outer sleeve of the metal composite pipe; The second layer extends to enclose and form a base pipe of the metal composite pipe; The inner wall of the base tube encloses and forms the inner cavity.

8. The shaped product according to claim 7, wherein: The thickness of the first layer is 2 to 300 times the thickness of the bonding layer; The thickness of the second layer is 6 to 2000 times the thickness of the bonding layer.

9. The shaped product according to claim 7, wherein: The ratio of the melting point of the third alloy to the melting point of the second alloy is 0.55 to 0.715; A ratio of a melting point of the third alloy to a melting point of the first alloy is 0.586 to 0.

853.

10. The shaped product according to claim 9, wherein The first alloy includes any one, any combination or all of alloy steel, 316L stainless steel, nickel-based alloy, cobalt-based alloy and titanium alloy; The second alloy includes any one or all of carbon steel and iron-based alloy; The third alloy includes any one, any combination or all of a nickel-based alloy, a cobalt-based alloy and an iron-based alloy doped with boron and / or silicon.

11. The shaped product according to claim 3 or 7, wherein: The radial cross-section of the metal composite pipe is circular, rectangular, regular polygonal or irregular polygonal; The first layer, the second layer and the bonding layer each have a substantially uniform thickness.

12. The shaped product according to claim 1, 4 or 8, wherein: The porosity of the bonding layer does not exceed 5%; The separation strength of the first layer and the second layer is greater than 300 MPa.

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