Non-stick cookware manufacturing method and titanium non-stick pan

Abstract

A non-stick cookware manufacturing method, comprising the following processing steps: S1, surface pretreatment: selecting at least two metal plates (1) and carrying out surface pretreatment; S2, layering: arranging the metal plates (1) in layers; S3, heating: heating the metal plates (1); S4, rolling: using a forming tool to roll the metal plates (1), so as to form a metal composite plate (5) having a first surface (51) and a second surface (52) opposite to each other, and forming a pattern of recesses and protrusions on the first surface (51) and / or the second surface (52) of the metal composite plate (5); S5, annealing: performing annealing treatment on the metal composite plate (5); and S6, stretching: stretching the metal composite plate (5) to form a pan body (10). A titanium non-stick pan, which is manufactured by the non-stick cookware manufacturing method.

Description

Method for manufacturing non-stick cookware and titanium non-stick cookware Technical Field

[0001] The invention relates to the technical field of cookware, and in particular to a method for manufacturing a non-stick cookware and a titanium non-stick cookware. Background Art

[0002] Currently, most cookware is made of composite plates, such as three-layer steel and steel-aluminum composite plates, which are formed by metallurgical bonding of multiple layers of metal. In order to achieve the effect of non-stick and protective coating, the pots made of composite plates generally have high and low sides. The low side has a non-stick coating in the groove, and the convex side contacts the spatula. The non-stick property of this type of pot is closely related to the ratio of the high and low sides.

[0003] In order to achieve the effect of non-stick and protective coating, cookware made of composite boards generally has high and low surfaces. These grooves are generally made by etching, but etching uses chemicals to corrode the metal to produce concave surfaces. This process is not environmentally friendly.

[0004] In the prior art, there is also a processing method of using a press to press out concave and convex patterns on purchased metal plates to process cookware, but the non-stick performance of such cookware is still not good enough, and consumers still hope that its non-stick performance will be further improved.

[0005] Titanium is widely used in kitchenware manufacturing due to its light weight, high strength, and excellent corrosion resistance. Existing titanium pots generally use etching to machine a concave-convex structure on the inner surface of the pot body to improve its non-stick properties. However, titanium alloy pots are relatively stable due to the metallic properties of titanium, which cannot be processed with ordinary etching solutions. They must be treated with strong acid solutions. This production method is not only costly but also poses safety and health risks to workers working in such an environment for a long time. Furthermore, most current methods of making etched titanium pots require the use of thicker materials, such as titanium metal materials that are at least 0.4mm thick. The thickness of the concave area after etching is about 0.2mm. It can be seen that the use of strong acid etching to process the concave-convex structure will remove material from the pot body, which not only wastes titanium, but also makes the concave area thinner and more prone to breakage during subsequent stretching of the pot body.

[0006] Furthermore, due to the varying sizes of food, small food items often end up in the concave portions of existing non-stick pans. This not only blocks the blind holes but can also cause food to get stuck in the cells, affecting the non-stick performance of the pan.

[0007] Therefore, it is very necessary to design a non-stick cookware manufacturing method and a titanium cookware that are easy to manufacture and can ensure good physical non-stick effect. Summary of the Invention

[0008] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a method for manufacturing a non-stick cookware and a titanium non-stick cookware, which can further improve the non-stick performance.

[0009] In a first aspect, in order to achieve the above-mentioned object, the present invention provides a method for manufacturing a non-stick cookware, comprising the following processing steps:

[0010] S1, surface pretreatment: select at least two metal plates for surface pretreatment;

[0011] S2, stacking; stacking the metal sheets;

[0012] S3, heating; heating the metal sheet;

[0013] S4, rolling; in a heated state, using a forming tool to roll the metal sheet to form a metal composite plate having opposite first and second surfaces, and forming a concave-convex pattern on the first surface and / or the second surface of the metal composite plate;

[0014] S5, annealing; annealing the metal composite plate;

[0015] S6, stretching; stretching the metal composite plate to form a pot body.

[0016] In the present invention, at least two metal sheets are selected and stacked and aligned, and then processed to form a metal composite plate with a concave-convex pattern. The metal composite plate can be made into a cookware through processes such as stretching, wherein the concave portion of the concave-convex pattern is used to spray a non-stick coating, and the convex portion is used to prevent the spatula from contacting the non-stick coating. In addition, the aforementioned at least two metal sheets can be homogeneous metal sheets or heterogeneous metal sheets. The metal sheets that have been heated and softened are rolled using a forming tool to form a composite metal plate with a concave-convex pattern. After the concave-convex pattern is formed on the metal composite plate, it is annealed to increase the ductility and toughness of the metal composite plate. In the related art, the concave-convex pattern is generally formed by knurling a formed metal composite plate purchased from a plate factory. The purchased formed metal composite plate has been heated once in the previous process, and its internal structure has changed. During the fabrication and forming of cookware, the metal composite sheet is typically reheated to facilitate stretching. This secondary heating causes the crystal grains to rearrange and form larger grains. Larger grains increase the width of the raised pattern formed during the subsequent knurling process, while the recessed area where the non-stick coating is applied decreases, resulting in poor non-stick properties in cookware made from the metal composite sheet. Furthermore, to reduce the difficulty of knurling, the purchased metal composite sheet must be reheated. Metal deforms more easily at high temperatures than at room temperature, and reheating wastes energy.

[0017] In the present invention, the knurling process is pre-installed during the first heating phase, allowing the pattern to be formed on the metal composite sheet during production. This means that the forming tool is used to composite multiple metal sheets and form the concave-convex pattern before the internal structure and grain size of the metal have changed. This process results in a narrower convex pattern, increasing the area of ​​the concave portion, improving the non-stick effect, saving steps, and increasing production efficiency. It should be noted that the knurling process can be performed simultaneously with the calendering and composite process of the metal sheets, or immediately after calendering.

[0018] Optionally, in step S4, the forming tool is a knurling machine equipped with at least two rollers, the two rollers respectively contacting the first and second surfaces of the metal composite sheet, and at least one of the rollers is configured with a concave-convex pattern. The metal sheet is rolled by the knurling machine to form a metal composite sheet with a concave-convex pattern. When the forming tool is only a knurling machine, the forming tool is equipped with at least two rollers corresponding to the first and second surfaces of the metal composite sheet, so that both opposing surfaces of the metal composite sheet are subjected to force, thereby achieving the purpose of composite during knurling. When both the roller contacting the first surface and the roller contacting the second surface are configured with concave-convex patterns, the concave-convex pattern is printed on both the first and second surfaces of the metal composite sheet after knurling. Of course, the concave-convex pattern can also be configured on only one of the rollers, and the type of roller is selected based on actual needs.

[0019] Optionally, in step S4, the forming tool is a rolling mill and a knurling machine, wherein the knurling machine is equipped with at least one roller with a concave-convex pattern; the metal sheet is first rolled in the rolling mill to form a metal composite plate, and then passed through the knurling machine to form the concave-convex pattern on the first surface and / or the second surface. When the forming tool is a rolling mill and a knurling machine, the metal sheet is rolled and composited in the rolling mill before immediately entering the knurling machine for knurling, thereby preventing the temperature drop of the metal sheet from affecting the knurling effect. Furthermore, the type and number of rollers in the knurling machine can be selected according to actual production requirements to form the concave-convex pattern on at least one side of the metal composite plate.

[0020] The metal composite sheet is continuously passed through a rolling mill and knurling machine, resulting in relatively uniform temperature and pressure. However, in related techniques, the purchased composite sheet is reheated before being processed on equipment such as a hydraulic press. This results in uneven temperature on the metal heating plate, and unstable pressure after prolonged operation. This affects the formation of the pattern on the metal composite sheet, resulting in unclear patterns on both sides of the sheet.

[0021] Optionally, in step S4, the rolling mill's rolling pressure is 100-1000t, and the temperature of the metal composite sheet while passing through the knurling machine is 220-400°C. Setting the rolling mill's rolling pressure to 100-1000t will result in poor metal sheet lamination when the rolling mill's pressure is less than 1200t, while roller wear is more likely when the rolling mill's rolling pressure exceeds 1800t. To ensure the knurling effect, the metal composite sheet must be kept at a certain temperature while passing through the knurling machine. At this temperature, the metal composite sheet is relatively soft, making it easier to print clear concave and convex patterns.

[0022] Optionally, in step S3, the metal sheet is placed in a heating furnace, and the temperature of the heating furnace is set to 300-500° C. When the temperature is greater than 500° C., the metal sheet is too soft to be processed, and when the temperature is less than 300° C., the metal sheet is still hard and the subsequent composite effect is poor.

[0023] Optionally, before or after step S5, step S51 may be further performed to form the metal composite sheet into a coil or cut it into sheets of desired shapes and sizes. The metal composite sheet may be formed into a coil or cut into sheets before annealing to facilitate subsequent processing or sale. Of course, the manufacturer or user may also form the metal composite sheet into a coil or cut it into sheets after annealing.

[0024] Optionally, in step S1, the selected metal plate is one or more of an iron plate, an aluminum plate, a titanium plate or a stainless steel plate. In order to improve the non-stick properties of the cookware made of the metal composite plate, the titanium plate can be used as the inner layer of the metal composite plate. Titanium metal has the advantages of high strength, high melting point, low density, and corrosion resistance. At the same time, titanium metal has good biological inertness and antibacterial properties, and no heavy metal precipitation occurs. Therefore, titanium metal is a good material for making cookware. At the same time, in order to reduce costs, the aluminum plate can be used as the outer layer or middle layer of the metal composite plate. In addition, such combinations should also be included in the scope of protection of this patent.

[0025] In the second aspect, in order to achieve the above-mentioned purpose of the invention, the present application also provides a titanium non-stick pan, including a pan body, the base material of the pan body is a multi-layer composite structure, the multi-layer composite structure includes a base metal layer and a titanium metal layer stacked together, the base metal layer is metallurgically bonded to the titanium metal layer, the thickness of the titanium metal layer is 0.25~0.4mm and forms a concave-convex structure with uniform thickness, the concave-convex structure includes a number of interconnected concave-convex cells, each of the concave-convex cells includes a first convex portion protruding from the inner surface of the pan body and a concave portion enclosed by the first convex portion, the concave portion includes a second convex portion arranged in the concave portion, the top of the second convex portion is lower than the top of the first convex portion, and the titanium metal layer forms an oxide layer with a thickness of 8~40um on the surface of the concave-convex structure.

[0026] In this technical solution, a titanium metal layer is set as the inner surface of the pot body, which can reduce the weight of the pot body and improve the strength and corrosion resistance of the pot body from the perspective of the material of the pot body; and a concave-convex structure is set on the titanium metal layer to improve the non-stick effect of the inner surface of the pot body. In addition, the thickness of the concave-convex structure on the titanium metal layer is uniform, which is different from the pot body processed by etching processing in the prior art, avoiding the problems of titanium waste and reduced pot body strength.

[0027] Moreover, the thickness of the titanium metal layer in this technical solution only needs to be 0.25~0.4mm, which saves about 12.5%~37.5% of titanium consumption compared to the thickness of titanium pots processed by traditional etching methods (at least 0.4mm), greatly reducing production costs.

[0028] The present technical solution also arranges a first raised portion, a recessed portion and a second raised portion in the recessed portion of the concave-convex structure. When in use, the second raised portion can prevent solid food from contacting the non-stick layer in the cells formed by the pattern. At the same time, the structure in which the second raised portion is lower than the first raised portion can form a concave arc between the two. Since the non-stick property of the non-stick pan is due to the principle of aerodynamics, most foods are irregular in shape, so the arc-shaped cells can be better sealed by the food. The hot air generated by the non-stick layer or the gaps are filled with cooking oil, forming a three-dimensional space for locking oil and storing air, which can better support the food and prevent food from clogging the recessed portion, thereby improving the non-stick effect. At the same time, by forming the first raised portion, the recessed portion and the second raised portion on the surface of the pot body to reduce the contact area between the food and the surface of the pot body, thereby reducing the friction between the food and the surface of the pot body, and further improving the non-stick effect.

[0029] Furthermore, the oxide layer includes a first oxide layer formed on the bottom and side surfaces of the recessed portion, the top and side surfaces of the second raised portion, and a second oxide layer formed on the top surface of the first raised portion. The first oxide layer has a thickness of 20 to 40 μm, and the second oxide layer has a thickness of 8 to 20 μm. The surface of the first raised portion is polished after oxidation to improve the quality of the inner surface of the pot and increase wear resistance. The first raised portion is higher than the recessed portion to prevent the oxide layer in the recessed portion from being polished, ensuring a high non-stick effect of the recessed portion.

[0030] Furthermore, the base metal layer is formed with protrusions on its surface. The metallurgical bonding between the base metal layer and the titanium layer creates a nested mortise and tenon joint structure. This creates a stronger bond between the two metals, improving the overall performance of the pot and reducing the amount of titanium used.

[0031] Furthermore, the width of the first protrusion is 0.2-0.5 mm, the height of the first protrusion is 0.08-0.25 mm, and the radial dimension of the recess is 2.5-3.5 mm.

[0032] Furthermore, the oxide layer is a titanium dioxide layer formed by micro-arc oxidation on the surface of the titanium metal layer. The oxide layer has a porous structure, with at least some of the pores interconnected. The titanium dioxide layer formed by micro-arc oxidation on the surface of the titanium metal layer is thicker and has a complex network of pores. The pores are interconnected, allowing for the storage of more oil molecules. Upon heating, the air within the pores expands, resulting in a more effective non-stick pan.

[0033] Furthermore, the first raised portion accounts for no more than 20% of the total area of ​​the concave-convex structure, and the concave portion accounts for no less than 80% of the total area of ​​the concave-convex structure. By controlling the ratio of the first raised portion to the concave portion, the area of ​​the concave portion and the area of ​​the non-stick zone are guaranteed, thereby improving the non-stick effect.

[0034] Furthermore, the second raised portion is arranged at the center of the recessed portion, the radial dimension of the second raised portion is 0.15-0.2 mm, and the height of the second raised portion is 0.05-0.1 mm lower than the height of the first raised portion.

[0035] Furthermore, the multi-layer composite structure of the pot body adopts a titanium-aluminum composite structure; or, the multi-layer composite structure of the pot body adopts a titanium-aluminum-steel composite structure and the base metal layer is located between the titanium metal layer and the steel metal layer.

[0036] Furthermore, the shape of the recessed portion formed by the first protruding portion is circular or regular polygonal.

[0037] Furthermore, the top ends of the first protrusion and / or the second protrusion are configured as pointed tips, thereby further reducing the contact area between the food and the pot body and improving the non-stick effect.

[0038] These features and advantages of the present invention will be further disclosed in the following detailed description and accompanying drawings. The preferred embodiments and means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present in each of the following text and accompanying drawings, they may be labeled with different symbols or numbers for convenience, but all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below in conjunction with the accompanying drawings:

[0040] FIG1 is a schematic diagram of the processing of a metal composite plate in the present invention;

[0041] FIG2 is a longitudinal cross-sectional view of the metal composite plate of the present invention;

[0042] FIG3 is a top view of the metal composite plate of the present invention;

[0043] FIG4 is an enlarged schematic diagram of FIG3A;

[0044] FIG5 is a schematic diagram of the structure of a metal composite plate with another pattern in the present invention;

[0045] FIG6 is a schematic structural diagram of point B in FIG5 ;

[0046] FIG7 is a schematic diagram of the overall structure of the pot body of the present invention;

[0047] FIG8 is a partial schematic diagram of a titanium-aluminum composite structure of the present invention;

[0048] FIG9 is a schematic diagram showing the dimensions of various parts of the concave-convex structure of the present invention;

[0049] FIG10 is a partial schematic diagram of the titanium-aluminum-steel composite structure of the present invention;

[0050] FIG11 is a schematic diagram of the distribution of the oxide layer at the concave-convex structure of the present invention;

[0051] FIG12 is a schematic diagram of a concave-convex structure according to one embodiment of the present invention;

[0052] FIG13 is a schematic diagram of the internal structure of an oxide layer according to one embodiment of the present invention;

[0053] FIG14 is a cross-sectional view of an oxide layer according to an embodiment of the present invention;

[0054] FIG15 shows the effect of the titanium non-stick pan provided in Example 1;

[0055] FIG16 shows the effect of the titanium non-stick pan provided in Example 2;

[0056] FIG17 shows the effect of the titanium non-stick pan provided in Example 3;

[0057] FIG. 18 shows the effect of the titanium pot provided in the comparative example.

[0058] Among them, 1. metal plate; 2. heating furnace; 3. rolling mill; 4. knurling machine; 5. metal composite plate; 51. first surface; 52. second surface; 53. boss; 54. groove; 10. pot body; 11. titanium metal layer; 12. base metal layer; 13. steel metal layer; 14. first raised portion; 15. recessed portion; 16. second raised portion; 17. oxide layer; 171. first oxide layer; 172. second oxide layer; 173. pore; 18. handle; 19. flange. DETAILED DESCRIPTION

[0059] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0060] Reference in this specification to "one embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment of the present patent disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment. Example

[0061] As shown in FIG1 , this embodiment provides a method for manufacturing a non-stick cookware, comprising the following processing steps:

[0062] S1, Surface Pretreatment: Select at least two rectangular or square metal sheets 1 (the number of metal sheets 1 can be two, three, or four, etc.) to form a multi-layer metal composite panel 5. The metal sheets 1 can be one or more of stainless steel, iron, aluminum, or titanium. Adjacent layers of metal sheets 1 can be made of the same or different metals. Surface pretreatment is performed on the selected metal sheets 1, i.e., the surfaces of the metal sheets 1 are cleaned to remove surface oil, oxides, etc.

[0063] In addition, the selected metal plates 1 should be of the same size for ease of processing. To improve the non-stick properties of the cookware made of the metal composite plate 5, a high-performance titanium plate can be used as the inner layer of the metal composite plate 5, while an aluminum plate or stainless steel plate can be used as the outer layer or middle layer of the metal composite plate 5 to reduce production costs.

[0064] S2, stacking: The clean metal sheets 1 that have undergone surface pretreatment are stacked one above the other, and the four corners of each metal sheet 1 are aligned. To ensure that the metal sheets 1 do not shift during subsequent steps, the corners of the metal sheets 1 can be fixed, such as by spot welding, to prevent the metal sheets 1 from shifting after rolling.

[0065] S3, Heating: The stacked and aligned metal sheets 1 are synchronously placed into a heating furnace 2 via a conveyor belt. The temperature of the heating furnace 2 is set between 300°C and 500°C. Within this temperature range, most metals, such as iron and aluminum, are softened, facilitating subsequent processing. It should be noted that after heating, the next step should be initiated quickly to prevent the metal sheets 1 from cooling and hardening, which could affect subsequent processing.

[0066] S4, rolling. In this embodiment, a knurling machine 4 with two rollers is used to process the softened metal sheet 1. The knurling machine 4 is set to a pressure of 100-1000 tons. The rollers roll the stacked and aligned metal sheets 1. After heating, the softened metal sheets 1 are combined into a single body, as shown in Figure 2, forming a metal composite plate 5 having opposing first and second surfaces 51, 52. Furthermore, at least one roller of the knurling machine 4 is provided with a concave-convex pattern. As the roller rolls the metal sheet 1, the concave-convex pattern is also imprinted on the first or second surface 51, 52 of the metal composite plate 5, as shown in Figure 3. When the cookware is subsequently manufactured, the side with the concave-convex pattern should serve as the inner surface of the cookware. The knurling and rolling processes are performed simultaneously, reducing production costs and improving efficiency.

[0067] In other embodiments, a rolling mill 3 and a knurling machine 4 may also be used for processing. Specifically, the stacked metal sheets 1 are first placed in a rolling mill 3 for rolling, with a rolling pressure of 100 to 1000 tons. The rolled and composite metal composite plate 5 is then placed in a knurling machine 4 for knurling. The knurling machine 4 is equipped with at least one roller with a concave and convex pattern to facilitate printing the pattern on the metal composite plate 5. It should be noted that after the metal composite plate 5 is processed in the rolling mill 3, it should be immediately placed in the knurling machine 4 to prevent the metal composite plate 5 from cooling and hardening, resulting in poor pattern processing results. Specifically, the temperature of the metal composite plate 5 when passing through the knurling machine 4 should be controlled at 220 to 400°C. This ensures uniform heating temperatures during the knurling and rolling processes, resulting in a more uniform concave and convex pattern with more consistent shape, depth, and thickness.

[0068] In addition, concave and convex patterns can also be formed on both the first surface 51 and the second surface 52 of the metal composite plate 5 , and this can be achieved by simply changing the type of roller used in the pattern forming tool, which is easy to operate and saves costs.

[0069] S5, annealing: annealing the metal composite plate 5. Preferably, the annealing should be performed under a reducing atmosphere or a vacuum environment.

[0070] S51: The metal composite plate 5 is rolled into a coil or cut into sheets of desired shapes and sizes. The metal composite plate 5 can be rolled into a coil or cut into sheets before annealing to facilitate subsequent processing or sale. In another embodiment, step S51 can also be performed before step S5, with the user or manufacturer rolling the metal composite plate 5 into a coil or cutting it into sheets.

[0071] S6, the metal composite plate 5 is stretched into the desired pot shape, and the side with the concave and convex pattern is used as the inner layer of the pot. Subsequently, the surface is subjected to micro-arcing, sanding, polishing, spraying, handle making, packaging and other processes according to the requirements of the pot.

[0072] This embodiment also provides a non-stick cookware, which is made by the aforementioned process steps. The metal composite plate 5 used is constructed in a rectangular shape, and its upper surface and / or lower surface is printed with a concave-convex pattern by the aforementioned process. As shown in Figures 3 and 4, the concave-convex pattern is composed of staggered bosses 53 and grooves 54, and a non-stick coating is sprayed in the groove 54. Of course, non-stick coatings processed by other methods should also be covered by the protection scope of this patent. The cookware is made of the metal composite plate 5 by stretching, and the side with the concave-convex pattern is used as the inner surface of the cookware. Since the boss 53 is higher than the groove 54, the spatula will first contact the boss 53 to avoid scratching the non-stick coating in the groove 54, thereby increasing the service life of the cookware.

[0073] In this embodiment, the grooves 54 are evenly or randomly distributed only on the inner surface of the metal composite plate 5, and the center-to-center distance between any two adjacent grooves 54 is 15 μm to 1.5 mm. If the center-to-center distance between adjacent grooves 54 is too small, the grooves 54 are too densely packed, making machining difficult and affecting the strength of the inner surface of the cookware. If the center-to-center distance between adjacent grooves 54 is too large, the grooves 54 are too sparsely packed, reducing the amount of oil that can be stored and degrading the non-stick properties. During actual use of the cookware, the grooves 54 absorb air and store grease. During heating, they generate hot air and oil mist, which can lift food. At the same time, these grooves 54 reduce the contact area between the food and the cookware, enhancing the physical non-stick effect. In other embodiments, the pattern can also be constructed in other styles. As shown in Figures 5 and 6, the grooves of the pattern are also provided with raised dots to further protect the non-stick coating.

[0074] Compared to the chemical etching method used in related art to create concave and convex patterns, the non-etching knurling process employed in this embodiment is more environmentally friendly. Furthermore, by pre-positioning the knurling process, the metal composite plate 5 does not need to be reheated for knurling. Furthermore, the properties of the annealed metal composite plate 5 are stable, and further heating and knurling can only produce a metal composite plate 5 with a wider raised pattern, not a finer one. This results in poor non-stick properties in the resulting cookware.

[0075] Referring to Figures 7, 8, and 10, this embodiment further provides a titanium non-stick pan, comprising a pan body 10. The base material of the pan body 10 is a multi-layer composite structure, comprising a titanium metal layer. The titanium metal layer forms the inner surface of the pan body. In this embodiment, the thickness of the titanium metal layer 11 is 0.25-0.4 mm, forming a uniform concave-convex structure. It should be noted that the uniform thickness herein refers to the uniform thickness of the titanium metal layer 11 throughout the entire concave-convex structure. For example, if the thickness of the titanium metal layer 11 is 0.3 mm, then the thickness of each portion of the concave-convex structure is uniformly 0.3 mm. This avoids the problem of etching the inner surface of the pan body 10, where the metal layer thickness of the concave portion 15 is thinner than that of the metal layer of the convex portion (inconsistent thickness of each portion). This ensures the strength and integrity of the pan body 10, facilitates stretch forming of the pan body 10 during production, improves the yield rate and quality of the pan body 10, and reduces the waste of titanium metal caused by etching.

[0076] Referring to Figures 8 and 10 , the concave-convex structure in this embodiment comprises a plurality of interconnected concave-convex units. Each concave-convex unit comprises a first raised portion 14 protruding from the inner surface of the pan body 10 and a recessed portion 15 enclosed by the first raised portion 14. The recessed portion 15 further comprises a second raised portion 16 disposed within the recessed portion 15. The top of the second raised portion 16 is lower than the top of the first raised portion 14. An oxide layer 17 with a thickness of 8 to 40 μm is formed on the titanium metal layer 11 at the surface of the concave-convex structure. During cooking, the oxide layer 17 comes into direct contact with food.

[0077] In actual use, the concave-convex structure on the inner surface of the pot body 10 has a non-stick effect, and its specific non-stick effect is mainly reflected in the following aspects:

[0078] 1) The non-stick effect is achieved through the structure of the concave-convex structure itself. The concave-convex structure can reduce the contact area between the inner surface of the pot body 10 and the food, thereby preventing the food from sticking to the inner surface of the pot body 10;

[0079] 2) The recessed portion 15 is designed so that during cooking, the mixture of oil and water will preferentially enter the recessed portion 15. When the pot body 10 is heated, the high-temperature steam generated by the oil and water will lift the food from the bottom, thereby preventing the food from standing on the inner surface of the pot body 10;

[0080] 3) The second raised portion 16 prevents smaller food from entering and clogging the recessed portion 15. The second raised portion 16 is lower than the first raised portion 14, creating a two-layer support structure for the food during cooking, preventing tiny food from adhering to the bottom of the recessed portion 15 and improving the non-stick effect. Furthermore, a concave arc-shaped structure is formed between the second raised portion 16 and the first raised portion 14. Since food is often irregularly shaped, the arc-shaped cell structure can better seal the food, making it easier for the non-stick layer to generate hot air, thereby better supporting the food.

[0081] 4) The setting of the oxide layer 17. An oxide layer 17 is formed on the surface of the first protrusion 14, the surface of the recessed portion 15, and the surface of the second protrusion 16. The oxide layer 17 in this embodiment is a titanium dioxide layer formed by micro-arc oxidation processing on the surface of the titanium metal layer 11. A porous structure is formed inside the oxide layer 17, and at least some of the pores are interconnected. The interior of the oxide layer 17 is a porous 173 structure, and the pores 173 can be interconnected. In this way, during actual cooking, the pores 173 will absorb oil and water molecules, and the interconnected structure will also improve the storage capacity of oil and water molecules. During cooking and heating, the oil and water molecules will evaporate into gas, thereby increasing the evaporation amount of the gas, which can better support the food and achieve a better non-stick effect.

[0082] In the step of micro-arc oxidation of the titanium metal layer 11 to obtain a titanium dioxide layer, a single pulse current source is used with a current density of 1.25~1.6A / dm 2 , the duty cycle is 12~15%, and the frequency is 500Hz.

[0083] As can be seen, this embodiment provides a titanium metal layer 11 on the inner surface of the pot body 10, which can reduce the weight of the pot body 10 and improve the strength and corrosion resistance of the pot body 10. The titanium metal layer 11 is also provided with a concave-convex structure to improve the non-stick effect of the inner surface of the pot body 10 (through the various structures mentioned above that improve the non-stick effect). In addition, the thickness of the concave-convex structure on the titanium metal layer 11 is uniform, which is different from the problem of titanium waste and reduced strength of the pot body 10 caused by the etching method in the prior art. In actual installation, the thickness of the titanium metal layer 11 in the present invention only needs to be 0.25-0.4mm. Compared with titanium non-stick pans processed by traditional etching methods (the thickness of the titanium metal layer 11 must be at least 0.4mm), it is equivalent to saving at least 12.5%-37.5% of titanium.

[0084] It should be noted that the concave-convex structure in the present invention may cover the entire inner surface of the pot body 10 , or may be provided on a portion of the inner surface.

[0085] Referring to FIG11 , the oxide layer 17 of one embodiment of the present invention includes a first oxide layer 171 formed on the bottom and side surfaces of the recessed portion 15 and the top and side surfaces of the second raised portion 16 , and a second oxide layer 172 formed on the top surface of the first raised portion 14 . The thickness of the first oxide layer 171 is 20 to 40 μm, and the thickness of the second oxide layer 172 is 8 to 20 μm. After the inner surface of the pot body 10 is oxidized, it is generally necessary to grind and polish the inner wall of the pot body 10 to remove impurities formed on the inner surface of the pot body 10 during the oxidation process and to improve the surface quality of the pot body 10. During the grinding and polishing process, the thickness of the oxide layer on the top surface of the first raised portion 14 will be thinned to a certain extent. However, since the oxide layer thickness of micro-arc oxidation is relatively thick, in actual production, a certain thickness of the first oxide layer 171 (8~20um) will still exist on the top surface of the first raised portion 14 after grinding. In addition, during the grinding process, due to the existence of the first raised portion 14, the inside of the recessed portion 15 and the surface of the second raised portion 16 will not be polished. At this time, the thickness of the second oxide layer 172 on the surface of the recessed portion 15 and the surface of the second raised portion 16 is relatively thick, and the non-stick effect that can be produced is also better. Moreover, the recessed portion 15 is also the main area that has the non-stick effect, thereby enabling the pot body 10 to achieve a better non-stick effect.

[0086] Referring to FIG. 9 , in one embodiment of the present invention, the width of the first raised portion 14 is set to L2 = 0.2-0.5 mm, and the height of the first raised portion 14 is set to H1 = 0.08-0.25 mm. The distance between two opposing points of the first raised portion 14 relative to the center of the recessed portion 15 is H2 = 2.5-3.5 mm. In actual implementation, the recessed portion 15 enclosed by the first raised portion 14 is configured to be circular or a regular polygon (typically a regular hexagon). When the recessed portion 15 is circular, the diameter is set to 2.5-3.5 mm. When the recessed portion 15 is a regular hexagon, the distance between two opposing lines is set to 2.5-3.5 mm.

[0087] The oxide layer 17 of the present invention is formed by micro-arc oxidation of the titanium metal layer 11. A porous structure 173 is formed within the oxide layer 17, and at least some of the pores 173 are interconnected. Compared to the oxide film formed by titanium anodization, the titanium dioxide (TiO2) oxide layer 17 formed by micro-arc oxidation of the titanium metal layer 11 is thicker, and the oxide layer 17 formed by micro-arc oxidation has a higher porosity 173 and roughness, and the film layer has good insulation properties. In addition, the voltage and current used in the micro-arc oxidation process are relatively high, generally requiring a voltage of 500V or more. In production, it is processed through a solution circulation process, so there is no emission and no pollution. The titanium oxide layer obtained in this way has a hardness of up to HV500-600 and has better wear resistance and corrosion resistance.

[0088] The oxide film produced by general titanium anodization is relatively dense and thin, only 0.5-2um thick. The voltage and current density during the anodization process are low, generally 15V~100V. Therefore, the oxide film produced has almost no hardness and is not wear-resistant. It is generally made into an oxidized color for the sake of the pot body 10's aesthetics, and pollutants need to be discharged during the process. Although the ordinary titanium anodized film can theoretically reach a thickness of 10~20um, it takes a long oxidation process to achieve a thickness of 10~20um, which is inefficient. The film layer of this anodized film is dense, and it takes a lot of time and cost to increase the thickness of the oxide film, but it does not improve the non-stick function. Therefore, in the prior art, it is generally necessary to treat the surface of the pot into a rough surface and then anodize the rough surface to achieve a certain non-stick property. Since the anodized film is relatively thin (generally only 0.5-2 μm), when the inner surface of the pot body 10 is polished after oxidation, the anodized film on the surface of the first raised portion 14 will be directly eliminated and the metal substrate will be exposed. As a result, when cooking, the food will directly contact the metal substrate, causing the problem of easy sticking to the pot. If it is not polished, the surface quality of the pot body 10 will be affected.

[0089] The oxide film produced by micro-arc oxidation (MAO) has a higher porosity and roughness, eliminating the need for roughening the substrate surface. Referring to Figures 13 and 8, the MAO-formed oxide layer 17 is thicker and contains complex pores 173 within it. These pores are interconnected, allowing the oxide layer 17 to store more oil molecules. During cooking, the air within the pores 173 expands, causing the stored oil molecules to evaporate into vapor, effectively supporting food and resulting in improved non-stick properties. Furthermore, because the MAO-formed oxide layer 17 is thicker, even after the top surface of the first raised portion 14 is polished for aesthetic reasons, a film layer 8 to 20 μm thick remains on the surface of the first raised portion 14 (no less than the thickness of the oxide layer 17 produced by anodizing). Therefore, combined with the thicker oxide layer 17 (20 to 40 μm) on the surfaces of the recessed portion 15 and the second raised portion 16, an even better non-stick effect is achieved.

[0090] The main area of ​​the titanium non-stick pan that has a non-stick effect is the recessed portion 15. Therefore, in order to ensure a better non-stick effect, the area of ​​the recessed portion 15 and the first raised portion 14 of the non-stick pan needs to reach a corresponding ratio. In one embodiment of the present invention, the first raised portion 14 accounts for no more than 20% of the area of ​​the entire concave-convex structure, and the recessed portion 15 accounts for no less than 80% of the entire concave-convex area. By controlling the ratio of the first raised portion 14 and the recessed portion 15, the area of ​​the recessed portion 15, that is, the area of ​​the area that mainly has a non-stick effect, is guaranteed, thereby improving the non-stick effect. In actual design, the proportion of the first raised portion 14 in the entire concave-convex structure can be comprehensively controlled by controlling the width and distribution density of the first raised portion 14.

[0091] Referring to Figures 8, 9, 10, 11, and 12, in one embodiment of the present invention, a second raised portion 16 is positioned at the center of the recessed portion 15. The diameter of the second raised portion 16 ranges from 0.15 to 0.2 mm, and the height of the second raised portion 16 is ΔH = 0.05 to 0.1 mm lower than the height of the first raised portion 14. By setting the height of the second raised portion 16 lower than the height of the first raised portion 14, the surface of the second raised portion 16 is not polished during polishing of the inner surface of the pot body 10. This allows the oxide layer 17 on both the second raised portion 16 and the recessed portion 15 to remain intact, while only a portion of the oxide layer 17 on the top surface of the first raised portion 14 is polished away, thereby improving the surface quality of the pot body 10. Furthermore, it is important to note that the second raised portion 16 forms a concave arc-shaped structure between the second raised portion 16 and the first raised portion 14, which further helps to support food and enhance the non-stick effect. Of course, setting the second raised portion 16 in the middle part of the recessed portion 15 is a preferred embodiment of the present application. The distance between the second raised portion 16 and the periphery of the first raised portion 14 is equal, so that the overall appearance of the pot body 10 is more beautiful and textured. In actual setting, the second raised portion 16 can also be set at a position deviating from the center of the recessed portion 15, and the number of the second raised portions 16 can also be set to multiple. It should be noted that when the number of the second raised portions 16 is set to multiple, the area of ​​the recessed portion 15 can be appropriately expanded, which is equivalent to reducing the area ratio of the first raised portion 14 and achieving a good non-stick effect.

[0092] The multi-layer composite structure of the pot body 10 of the present invention can adopt a double-layer metal structure of titanium and aluminum composite, in which case the titanium layer forms the inner surface of the pot body 10 and the aluminum layer forms the outer surface of the pot body 10; or, the multi-layer composite structure of the pot body 10 can also adopt a three-layer metal structure of titanium, aluminum and steel composite, in which case the base metal layer 12 is located between the titanium metal layer 11 and the steel metal layer 13, and the metal layers of the pot body 10 from the outside to the inside are steel, aluminum, and titanium, respectively.

[0093] When the pot body 10 of the present invention is manufactured, the multiple layers of metal plates of the composite pot are formed by hot pressing and compounding. In the hot pressing and compounding process, larger metal plates can be continuously rolled to form multiple composite metal plates of the size of the pot body 10. The concave-convex structure is directly pressed during the compounding process. Therefore, although the inner surface of the pot body 10 has a first convex portion 14 and a concave portion 15, the thickness of the titanium metal layer 11 on its inner surface is uniform (the thickness of each part of the concave-convex structure is consistent). In addition, since aluminum is softer than titanium, the titanium metal layer 11 undergoes plastic deformation under the action of pressure during rolling, and the base metal layer 12 also deforms accordingly. Before rolling, protrusions are set on the surface of the base metal layer 12. During the rolling process of the base metal layer 12 and the titanium metal layer 11, the protrusions on the surface of the base metal layer 12 and the concave-convex structure of the titanium metal layer 11 form a mutually nested mortise and tenon connection structure, see Figures 11 and 6. In this way, the two metals can achieve better bonding strength, improve the overall effect of the pot body 10, and reduce the amount of titanium metal used. The metal plate formed in this way can use a thinner titanium metal layer 11, that is, the formed pot has a concave-convex structure on the inner surface, an inlaid structure in the middle, and the back surface can be freely selected to have a pattern or a flat surface.

[0094] Referring to FIG11 , the top surfaces of the first and second raised portions 14, 16 in the concave-convex structure of the present invention can be flat. In one embodiment of the present invention, the tops of the first and / or second raised portions 14, 16 are configured as pointed. Referring to FIG12 , both the tops of the first and second raised portions 14, 16 are configured as pointed. This reduces the contact area between food and the pot body 10 during cooking (compared to a configuration where the tops of the first and second raised portions 14, 16 are flat), achieving a better non-stick effect. Furthermore, it is contemplated that, in actual designs, the tops of the first and second raised portions 14, 16 can be both flat and pointed, or one can be flat and the other can be pointed. It should be noted that when the tops of the first and second raised portions 14, 16 are configured as pointed, the width of the first and second raised portions 14, 16 refers to the width of their bases.

[0095] Of course, the pot body 10 of the present invention may also be provided with a handle 18, wherein the handle 18 is made of a material with poor thermal conductivity, such as wood or rubber, and is detachably connected to the pot body 10. The opening edge of the pot body 10 may also be provided with a flange 19, which improves the overall appearance of the pot, enhances the strength of the pot body 10, and improves safety during use (to prevent burns, scratches, etc.).

[0096] Table 1 shows the parameters of the titanium non-stick pans according to three different embodiments of the present invention, as well as the parameters of a comparative example of a titanium pan.

[0097] Table 1

[0098] It should be noted that the oxide layers in Examples 1 to 3 are all formed by micro-arc oxidation, while the oxide layer of the titanium pot provided in the comparative example is formed by anodic oxidation.

[0099] Test Case

[0100] After heating the pan on a gas stove for 2 minutes, a raw egg was added. Figure 15 shows the effect of the titanium non-stick pan provided in Example 1; Figure 16 shows the effect of the titanium non-stick pan provided in Example 2; Figure 17 shows the effect of the titanium non-stick pan provided in Example 3; and Figure 18 shows the effect of the titanium pan provided in the comparative example.

[0101] It can be seen from Figures 15 to 18 that the titanium non-stick pans of Examples 1 to 3 have little food residue and good non-stick effect, while the titanium pan of the comparative example has relatively more food residue and relatively poor non-stick effect.

[0102] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A method for making a non-stick cookware, characterized in that: The processing steps include: S1, surface pretreatment: selecting at least two metal plates (1) for surface pretreatment; S2, stacking; stacking the metal sheets (1); S3, heating: heating the metal sheet (1); S4, rolling: in a heated state, using a forming tool to roll the metal sheet (1) to form a metal composite plate (5) having a first surface (51) and a second surface (52) opposite to each other, and forming a concave-convex pattern on the first surface (51) and / or the second surface (52) of the metal composite plate (5); S5, annealing: annealing the metal composite plate (5); S6, stretching; stretching the metal composite plate (5) to form a pot body.

2. The method for making a non-stick cookware according to claim 1, characterized in that: In step S4, the forming tool is a knurling machine (4) equipped with at least two rollers, the two rollers are in contact with the first surface (51) and the second surface (52) of the metal composite plate (5) respectively, and at least one of the rollers is equipped with a concave-convex pattern; the metal sheet (1) is rolled by the knurling machine (4) to form a metal composite plate (5) with a concave-convex pattern.

3. The method for making a non-stick cookware according to claim 1, characterized in that: In step S4, the forming tools are a rolling machine (3) and a knurling machine (4), wherein the knurling machine (4) is equipped with at least one roller with a concave-convex pattern; the metal sheet (1) is first rolled by the rolling machine (3) to form a metal composite plate (5), and then passes through the knurling machine (4) to form a concave-convex pattern on the first surface (51) and / or the second surface (52).

4. The method for making a non-stick cookware according to claim 3, characterized in that: In step S4, the rolling pressure of the rolling mill (3) is 100-1000 t, and the temperature of the metal composite plate (5) when passing through the knurling machine (4) is 220-400°C.

5. The method for making a non-stick cookware according to any one of claims 1 to 4, characterized in that: In step S3, the metal plate (1) is placed in a heating furnace (2), and the temperature of the heating furnace (2) is set to 300-500°C.

6. The method for making a non-stick cookware according to any one of claims 1 to 4, characterized in that: Before or after step S5, there is also a step S51 of making the metal composite plate (5) into a coil or cutting it into sheets of required shape and size.

7. The method for making a non-stick cookware according to any one of claims 1 to 4, characterized in that: In step S1, the selected metal plate (1) is one or more of an iron plate, an aluminum plate, a titanium plate or a stainless steel plate.

8. A titanium non-stick pan, comprising a pan body (10), characterized in that: The base material of the pot body (10) is a multi-layer composite structure, the multi-layer composite structure comprising a stacked base metal layer (12) and a titanium metal layer (11), the base metal layer (12) being metallurgically bonded to the titanium metal layer (11), the titanium metal layer (11) having a thickness of 0.25-0.4 mm and forming a concave-convex structure with uniform thickness, the concave-convex structure comprising a plurality of mutually connected concave-convex cells, each of the concave-convex cells comprising a first protruding portion (14) protruding from the inner surface of the pot body (10) and a concave portion (15) formed by the first protruding portion (14), the concave portion (15) comprising a second protruding portion (16) arranged in the concave portion (15), the top of the second protruding portion (16) being lower than the top of the first protruding portion (14), and the titanium metal layer (11) forming an oxide layer (17) with a thickness of 8-40 μm on the surface of the concave-convex structure.

9. The titanium non-stick pan according to claim 8, characterized in that: The oxide layer (17) comprises a first oxide layer (171) formed on the bottom surface and side surfaces of the recessed portion (15) and the top surface and side surfaces of the second protruding portion (16); the oxide layer (17) further comprises a second oxide layer (172) formed on the top surface of the first protruding portion (14); the thickness of the first oxide layer (171) is 20 to 40 μm, and the thickness of the second oxide layer (172) is 8 to 20 μm.

10. The titanium non-stick pan according to claim 8, characterized in that: The surface of the base metal layer (12) is formed with protrusions, and the metallurgical bonding of the base metal layer (12) and the titanium metal layer (11) enables the protrusions on the surface of the base metal layer (12) and the concave-convex structure of the titanium metal layer (11) to form a mutually nested mortise and tenon connection structure.

11. The titanium non-stick pan according to claim 8, characterized in that: The width of the first protrusion (14) is 0.2-0.5 mm, and the height of the first protrusion (14) is 0.08-0.25 mm.

12. The titanium non-stick pan according to claim 8, characterized in that: The oxide layer (17) is a titanium dioxide layer formed by micro-arc oxidation of the surface of the titanium metal layer (11), and a multi-pore (173) structure is formed inside the oxide layer (17), and at least some of the pores (173) are interconnected.

13. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The first raised portion (14) accounts for no more than 20% of the entire concave-convex structure area, and the recessed portion (15) accounts for no less than 80% of the entire concave-convex structure area.

14. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The second raised portion (16) is arranged at the center of the recessed portion (15), the diameter of the second raised portion (16) is 0.15-0.2 mm, and the height of the second raised portion (16) is 0.05-0.1 mm lower than the height of the first raised portion (14).

15. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The base metal layer (12) is set as an aluminum metal layer, and the multi-layer composite structure of the pot body (10) also includes a steel metal layer (13) located at the bottom of the base metal layer (12).

16. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The shape of the recessed portion (15) formed by the first raised portion (14) is circular or regular polygonal.

17. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The top end of the first protrusion (14) and / or the second protrusion (16) is configured as a pointed end.

18. The titanium non-stick pan according to any one of claims 8 to 12, characterized in that: The pot body (10) is obtained by using the manufacturing method of the non-stick cookware according to any one of claims 1 to 7.

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