Energy-saving cookware based on composite material and preparation process of energy-saving cookware

Abstract

The pot comprises a substrate layer, a heat conduction and storage layer and a contact layer which are sequentially compounded from outside to inside, and the heat conduction and storage layer is a novel aluminum-based composite material. The aluminum-silicon alloy composite material is prepared from an aluminum-silicon alloy matrix, nano aluminum nitride, micron-sized crystalline flake graphite and rare earth oxide according to a specific ratio, and has the characteristics of high heat conductivity and high heat storage; the preparation technology comprises the steps of raw material pretreatment, preparation of a heat conduction and heat storage layer prefabricated blank through high-energy ultrasonic-assisted melt compounding, three-layer metallurgical bonding achieved through vacuum hot pressing, atmosphere protection heat treatment and final forming, and the technical problems that heat conduction and heat storage of a traditional pot are difficult to achieve at the same time, and layers are prone to layering are solved. The energy-saving pot is high in heat efficiency, long in service life and feasible in process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cooking utensil devices, in particular to an energy-saving cooking utensil based on composite materials and a preparation process thereof. BACKGROUND

[0002] Traditional cooking utensils are mostly made of single metal materials (such as iron, aluminum, stainless steel), which have problems such as uneven heat conduction, local overheating, and low thermal efficiency. In order to improve performance, multi-layer composite structure cooking utensils have appeared, which usually adopt a sandwich structure of "stainless steel-aluminum-stainless steel" or "stainless steel-pure aluminum-stainless steel", and utilize the high thermal conductivity of aluminum to improve heat distribution.

[0003] However, the prior art still has the following deficiencies:

[0004] 1. Difficulty in balancing heat conduction and heat storage: pure aluminum or aluminum alloy has good thermal conductivity, but the specific heat capacity is limited, and the heat storage capacity is insufficient, resulting in poor cooking effect after the fire is turned off.

[0005] 2. Material performance bottleneck: the thermal conductivity coefficient and specific heat capacity of conventional metal materials have reached their physical limits, and it is difficult to achieve a breakthrough in energy-saving effect.

[0006] 3. Interlayer bonding strength: under cold and hot cycles, the difference in thermal expansion coefficients between different metal layers easily leads to interfacial stress, and long-term use may cause delamination and deformation.

[0007] 4. Process complexity: existing multi-layer composite processes (such as explosive compounding and rolling compounding) have high requirements for equipment, high costs, and are difficult to accurately control the composition and structure of the intermediate functional layer.

[0008] Therefore, there is an urgent need in the art for an energy-saving cooking utensil that has excellent thermal conductivity, high heat storage, long-term structural stability, and reasonable preparation cost. SUMMARY

[0009] (I) Technical problem

[0010] The present application aims to overcome the above-mentioned deficiencies of the prior art and provide an energy-saving cooking utensil based on composite materials and a preparation process thereof.

[0011] (II) Technical content

[0012] To solve the above technical problems, the technical solution of the present application is as follows: an energy-saving cooking utensil based on composite materials, comprising a base layer, a heat conduction and storage layer, and a contact layer which are sequentially compounded from the outside to the inside; the heat conduction and storage layer is made of a composite material, and its formula composition by mass percentage is: aluminum-silicon alloy matrix: 85-92%, nano-aluminum nitride: 5-10%, micron-scale flake graphite: 2-4%, rare earth oxide: 0.5-1%; wherein the mass percentage of silicon in the aluminum-silicon alloy matrix is 10-15%.

[0013] Further, the thickness of the heat-conducting and heat-storing layer is 50-70% of the total thickness of the main body of the pot.

[0014] Further, the base layer is a 430 or 304 stainless steel layer, and the contact layer is a 304 or 316L stainless steel layer.

[0015] Further, the thickness ratio of the base layer to the contact layer is 1:1.2-1.5.

[0016] Another aspect of the present application provides a preparation process of an energy-saving pot based on a composite material, comprising the following steps:

[0017] S1. Raw material preparation and pretreatment: weigh the aluminum-silicon alloy ingot, nano-aluminum nitride powder, micron-scale flake graphite, and rare earth oxide according to the formula; perform surface modification treatment on the nano-aluminum nitride and micron-scale flake graphite by placing them in an ethanol solution of silane coupling agent and ultrasonic dispersion for 30-60 minutes, and dry them for standby use; prepare metal plate blanks with uniform thickness for the base layer and the contact layer;

[0018] S2. Pre-forming of the heat-conducting and heat-storing layer: melt the aluminum-silicon alloy ingot, and in the molten state, add the nano-aluminum nitride, micron-scale flake graphite, and rare earth oxide pretreated in step S1, and use high-energy ultrasonic assisted mechanical stirring for 40-80 minutes to uniformly mix them; prepare a foil strip by rapid solidification technology, or prepare a preform by cold pressing after atomizing the melt into a composite powder;

[0019] S3. Assembly of the multi-layer structure: stack the base layer, the preform of the heat-conducting and heat-storing layer, and the contact layer in order to assemble a composite blank;

[0020] S4. Vacuum hot pressing and compounding: place the composite blank obtained in step S3 into a vacuum hot pressing furnace, and vacuumize to below 1×10-2 Pa; at a temperature of 580-620℃ and a pressure of 25-35 MPa, keep the temperature and pressure for 60-120 minutes to make the three layers realize metallurgical bonding;

[0021] S5. Atmosphere protection heat treatment and forming: after hot pressing, the composite plate blank is subjected to solution treatment under argon protection: heat to 500-530℃, keep the temperature for 1-2 hours, and then water quenching; then perform aging treatment, i.e. heat to 160-200℃, keep the temperature for 4-8 hours, and cool down in the furnace; finally, the heat-treated composite plate blank is processed into a pot shape by spinning or stamping process.

[0022] Further, in step S2, the frequency of the high-energy ultrasonic is 20-25 kHz, and the power is 1.5-2.5 kW; the rapid solidification technology is single-roll strip casting, and the cooling roll linear speed is not less than 30 m / s.

[0023] Further, in step S4, the rate of temperature rise to the hot-pressing temperature is 5-10℃ / min, and before the pressure is applied, preheating is performed at 450℃ and a pre-pressure of 5-10MPa is applied.

[0024] (III) Technical effects

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1. Because the heat-conducting and heat-storing layer has high thermal conductivity (≥220W / m·K) and high specific heat capacity (≥1100J / kg·K), the heat absorption of the bottom of the pot is rapid and uniform, and the thermal efficiency is improved by about 30%-40%, thereby effectively saving energy.

[0027] 2. The excellent heat conductivity eliminates local overheating and avoids food burning; and the strong heat-storing capacity enables the pot body to maintain high temperature for a long time after the fire is turned off or switched to small fire, which is particularly suitable for stewed dishes, and realizes the effect of "cooking after turning off the fire".

[0028] 3. Through the optimized preparation process, firm metallurgical bonding between the layers of the pot body is realized, and the bonding strength is high. The thermal expansion coefficients of the newly created material layer and the inner and outer metal layers are matched and designed, which greatly reduces the internal stress under cold and hot cycles, avoids delamination and deformation, and prolongs the service life.

[0029] 4. The integrated process of "pre-forming-vacuum hot pressing-atmosphere protection heat treatment" solves the technical problems of difficulty in compounding of high-proportion ceramic phase and metal matrix and easy oxidation, the process flow is reasonable, the yield of finished products is high, and the process is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic diagram of the three-dimensional structure of an energy-saving pot based on a composite material according to the present application.

[0031] Figure 2 is a schematic diagram of the layered structure of an energy-saving pot based on a composite material according to the present application.

[0032] Figure 3 is a process flow diagram for preparing an energy-saving pot based on a composite material according to the present application.

[0033] As shown in the figure: 1, base layer; 2, heat-conducting and heat-storing layer; 3, contact layer. DETAILED DESCRIPTION

[0034] In the description of the present application, it is to be understood by those skilled in the art that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer", "center" and the like indicate the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation configuration and operation, and therefore cannot be understood as a limitation on the present application.

[0035] In the description of the present application, it is to be understood by those skilled in the art that the terms "provided with", "mounted", "connected", "connected" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] The present application will be further described in detail below in conjunction with the embodiments.

[0037] Example 1

[0038] The present embodiment provides a composite material-based energy-saving wok and a preparation method thereof.

[0039] Wok structure:

[0040] The wok body is a three-layer composite structure, from the outside to the inside in turn: base layer 1 (material 430 stainless steel, thickness 1.2 mm), heat-conducting and heat-storing layer 2 (thickness 3.0 mm), contact layer 3 (304 stainless steel, thickness 1.5 mm). The proportion of heat-conducting and heat-storing layer 2 to the total thickness is 52.6%.

[0041] Heat-conducting and heat-storing layer formula (by mass percentage): aluminum-silicon alloy matrix 89% (of which the silicon content is 12%); nano-aluminum nitride 7% (average particle size 50 nm); micron-scale flake graphite 3% (particle size 5-15 μm); yttrium oxide (Y2O3) 1%.

[0042] Preparation process:

[0043] 1. Raw material pretreatment: put the nano-aluminum nitride and micron-scale flake graphite into the ethanol solution (concentration 2%) of KH-550 silane coupling agent, ultrasonic dispersion for 45 minutes, and then dry in a vacuum oven at 80°C.

[0044] 2. Preparing the heat-conducting and heat-storing layer: The Al-Si alloy ingot was melted into a melt at 780°C under argon protection. The pretreated reinforcing agent powder (nano-aluminum nitride, flake graphite, yttrium oxide) was preheated to 300°C and then added into the melt in batches. The reinforcing agent was uniformly dispersed by mechanical stirring (500 rpm) combined with high-energy ultrasonic treatment (22 kHz, 2.0 kW) for 60 minutes. Subsequently, the composite melt was rapidly solidified by a single-roller tape casting method to prepare a composite foil with a thickness of about 0.1 mm. The foils were stacked and cold-pressed into a dense preform with a thickness of 3.0 mm.

[0045] 3. Assembling the multilayer structure: The 430 stainless steel plate (base layer), the heat-conducting and heat-storing layer preform, and the 304 stainless steel plate (contact layer) were stacked in order. After cleaning the contact surfaces of each layer, the composite blank was assembled.

[0046] 4. Vacuum hot pressing: The composite blank was placed in a vacuum hot pressing furnace and vacuumed to 5 x 10-3 Pa. The temperature was raised to 600°C at a rate of 8°C / min, and a pre-pressure of 8 MPa was applied at 450°C. After reaching 600°C, a pressure of 30 MPa was applied, and the temperature was maintained for 90 minutes.

[0047] 5. Atmosphere protection heat treatment and forming: After hot pressing, high-purity argon was filled into the furnace. Solution treatment was performed by raising the temperature to 520°C and maintaining it for 1.5 hours, followed by water quenching. Subsequently, aging treatment was performed by raising the temperature to 180°C and maintaining it for 6 hours, followed by furnace cooling. Finally, the composite plate blank was processed into a frying pan shape by a numerical control spinning machine, and surface polishing treatment was performed.

[0048] Example 2

[0049] This example provides an energy-saving soup pot focusing on heat storage performance and a preparation method thereof.

[0050] Pot structure:

[0051] The pot body is a three-layer composite structure, from the outside to the inside: base layer 1 (304 stainless steel, thickness 1.0 mm), heat-conducting and heat-storing layer 2 (thickness 4.2 mm), and contact layer 3 (316L stainless steel, thickness 1.8 mm). The heat-conducting and heat-storing layer 2 accounts for 60% of the total thickness.

[0052] Heat-conducting and heat-storing layer formula (by mass percentage): Al-Si alloy matrix 92% (with a silicon content of 10%); nano-aluminum nitride 5% (average particle size 80 nm); micron-scale flake graphite 2.5% (particle size 10-20 μm); cerium oxide (CeO2) 0.5%.

[0053] Preparation process:

[0054] 1. Raw material pretreatment: same as Example 1.

[0055] 2. Preform of the heat conducting and heat storing layer: Al-Si alloy was melted at 750 °C. The preheated reinforcing powder was added into the melt. The composite melt was mechanically stirred for 80 min with the assistance of high power ultrasound (frequency 20 kHz, power 1.8 kW). Then the composite melt was atomized by inert gas to form spherical composite powder. The composite powder was cold pressed into 4.2 mm thick preform in a mold.

[0056] 3. Assembly of the multilayer structure: same as example 1, the base layer, the preform and the contact layer were stacked in sequence.

[0057] 4. Vacuum hot pressing: vacuum was drawn to 1 x 10"2Pa. The temperature was raised to 580 °C at a rate of 5 °C / min, and a pre-pressure of 10 MPa was applied at 500 °C. After reaching 580 °C, a pressure of 35 MPa was applied, and the temperature was kept for 120 min.

[0058] 5. Atmosphere protection heat treatment and forming: solution treatment (500 °C, 2 h, water quenching) and aging treatment (160 °C, 8 h) were carried out under argon atmosphere. Finally, the deep drawing and the deep drawing were carried out by hydraulic press with mold to form the pot body.

[0059] Example 3

[0060] The present example provides an energy-saving frying pan pursuing heat conducting performance and a preparation method thereof.

[0061] Pot structure:

[0062] The pot body is a three-layer composite structure, from outside to inside: base layer 1 (430 stainless steel, thickness 1.5 mm), heat conducting and heat storing layer 2 (thickness 2.5 mm), and contact layer 3 (304 stainless steel, thickness 1.0 mm). The heat conducting and heat storing layer 2 accounts for 50% of the total thickness.

[0063] Heat conducting and heat storing layer formula (by mass percentage): Al-Si alloy matrix 85% (of which the silicon content is 15%); nano-aluminum nitride 10% (average particle size 30 nm); micron-scale flake graphite 4% (particle size 2-8 μm); lanthanum oxide (La2O3) 1%.

[0064] Preparation process:

[0065] 1. Raw material pretreatment: same as example 1.

[0066] 2. Preform of the heat conducting and heat storing layer: Al-Si alloy was melted at 800 °C. The pre-processed reinforcing agent was added, and the mechanical stirring was assisted by high power ultrasound (frequency 25 kHz, power 2.5 kW) for 40 min. Then the composite foil was prepared by single roller tape casting method (cooling roller linear speed 35 m / s), and cold pressed into 2.5 mm thick preform.

[0067] 3. Multilayer structure assembly: same as example 1.

[0068] 4. Vacuum hot-pressing compounding: vacuum extraction to 5x10-3Pa. Temperature rise to 620℃ at a rate of 10℃ / min, 5MPa pre-pressure applied at 400℃. After reaching 620℃, 25MPa pressure applied, holding for 60 minutes.

[0069] 5. Atmosphere-protected heat treatment and molding: solid solution treatment (530℃, holding for 1 hour, water quenching) and aging treatment (200℃, holding for 4 hours) under argon protection. Finally, punch molding into a wok shape.

[0070] The wok samples prepared in the above three examples were tested for performance and compared with a traditional aluminum alloy wok of a well-known brand in the market (comparative example). Test items included:

[0071] 1. Thermal conductivity: laser thermal conductivity instrument was used to test the thermal conductivity of the heat-conducting and heat-storing layer material.

[0072] 2. Specific heat capacity: differential scanning calorimetry (DSC) was used for testing.

[0073] 3. Thermal efficiency: under the same heat source and water quantity, the time and energy consumption required to heat water from 25℃ to 90℃ were measured, and the thermal efficiency was calculated, according to the national standard.

[0074] 4. Temperature uniformity: thermal imager was used to observe the temperature distribution of the wok bottom under constant heating power.

[0075] 5. Bonding strength: ultrasonic flaw detection was used to detect the interlayer bonding, and samples were taken for shear strength testing.

[0076] Test results are shown in the following table:

[0077]

[0078] From the test results, it can be seen that the energy-saving wok prepared by the present application has a heat-conducting and heat-storing layer material with a thermal conductivity and specific heat capacity much higher than that of traditional aluminum alloy. This makes the wok perform significantly better in terms of heat conduction speed, heat distribution uniformity and heat storage capacity, thereby achieving high thermal efficiency and excellent "stir-frying after turning off the fire" effect. At the same time, the woks of all examples have good interlayer bonding, proving the reliability and effectiveness of the preparation process of the present application.

[0079] The above describes the present application and its embodiments, which are not limited, and the drawings only show one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired thereby, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solution are not creative, and should belong to the protection scope of the present application.

Claims

1. An energy saving cookware based on composite material, characterized in that, It comprises, from outside to inside, a base layer (1), a heat-conducting and heat-storing layer (2) and a contact layer (3) which are sequentially compounded; The heat-conducting and heat-storing layer (2) is made of a composite material, and its formula comprises, by mass percentage: Aluminum-silicon alloy matrix: 85-92%, Nano-aluminum nitride: 5-10%, Micron-scale flake graphite: 2-4%, Rare earth oxide: 0.5-1%; The mass percentage of silicon in the aluminum-silicon alloy matrix is 10-15%.

2. An energy saving cookware based on composite material as claimed in claim 1, wherein, The thickness of the heat-conducting and heat-storing layer (2) is 50%-70% of the total thickness of the main body of the pot.

3. An energy saving cookware based on composite material as claimed in claim 2 wherein, The base layer (1) is a 430 or 304 stainless steel layer, and the contact layer (3) is a 304 or 316L stainless steel layer.

4. An energy saving cookware based on composite material as claimed in claim 3 wherein, The thickness ratio of the base layer (1) to the contact layer (3) is 1:1.2-1.

5.

5. A process for the production of the energy saving composite material based cookware as claimed in any one of the claims 1 to 4, wherein, It comprises the following steps: S1. Raw material preparation and pretreatment: weigh the aluminum-silicon alloy ingot, nano-aluminum nitride powder, micron-scale flake graphite and rare earth oxide according to the formula; surface modification treatment is performed on the nano-aluminum nitride and micron-scale flake graphite, which is placed in an ethanol solution of silane coupling agent and ultrasonically dispersed for 30-60 minutes, and then dried for standby use; prepare metal slab blanks of the base layer (1) and the contact layer (3) with uniform thickness; S2. Heat-conducting and heat-storing layer pre-forming: melt the aluminum-silicon alloy ingot, and in the molten state, add the nano-aluminum nitride, micron-scale flake graphite and rare earth oxide pretreated in step S1, and uniformly mix them by using high-energy ultrasonic assisted mechanical stirring for 40-80 minutes; the uniformly mixed melt is made into a foil strip by rapid solidification technology, or the melt is atomized into a composite powder which is then cold-pressed into a pre-forming blank; S3. Multi-layer structure assembly: stack the base layer (1), the heat-conducting and heat-storing layer pre-forming blank and the contact layer (3) in order to assemble a composite blank; S4. Vacuum hot pressing: place the composite blank obtained in step S3 into a vacuum hot pressing furnace, and vacuumize to below 1×10-2 Pa; at a temperature of 580-620℃ and a pressure of 25-35 MPa, keep the temperature and pressure for 60-120 minutes, so that the three layers of materials are metallurgically bonded; S5. Atmosphere protection heat treatment and forming: the hot-pressed composite slab blank is subjected to solution treatment under argon protection: heat to 500-530℃, keep for 1-2 hours, and then water quench; then, aging treatment is performed, i.e. heat to 160-200℃, keep for 4-8 hours, and cool down in the furnace; finally, the heat-treated composite slab blank is processed into a pot shape by spinning or stamping process.

6. The manufacturing process of claim 5, wherein, In step S2, the frequency of the high-energy ultrasonic is 20-25 kHz, and the power is 1.5-2.5 kW; the rapid solidification technology is single-roll strip casting, and the cooling roll linear speed is not less than 30 m / s.

7. The manufacturing process of claim 5, wherein, In step S4, the heating rate to the hot pressing temperature is 5-10℃ / min, and before applying the pressure, preheat at 450℃ and apply a pre-pressure of 5-10 MPa.

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