Machining method of cast iron stove

Abstract

The invention relates to the field of metallurgical engineering, and discloses a cast iron stove processing method which comprises the following steps: S1, selecting a cast iron alloy material and preparing an alloy through a vacuum melting process; s2, casting the alloy material into a cast iron stove part; s3, a coating is applied to the surface of the cast iron stove; s4, plasma spraying and laser surface treatment are conducted on the coating; s5, carrying out heat treatment and cooling on the cast iron stove; s6, the treated cast iron stove is assembled, and the cast iron stove is obtained; the cast iron alloy material in the step S1 comprises a high-chromium molybdenum alloy, iron and a phase change alloy, and the chromium content of the high-chromium molybdenum alloy is 15%-25%. A coating with a three-layer structure is applied to the surface of a cast iron stove, and comprises a high-temperature-resistant substrate layer, a photocatalytic functional layer and a super-hydrophobic corrosion-resistant layer, so that the functions of high-temperature protection, photocatalytic decomposition of pollutants and corrosion prevention are respectively provided.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical engineering, in particular to a method for processing a cast iron furnace. Background Art

[0002] Cast iron stoves are widely used in industrial production and daily life. Their main function is to provide high temperature treatment and heat conduction. In the production of traditional cast iron stoves, cast iron materials are widely used for their good thermal conductivity and high temperature stability. However, with the deterioration of the stove use environment (such as high temperature, corrosive gas, corrosive liquid, etc.), traditional cast iron stoves often face many difficult challenges during use, especially in terms of high temperature resistance, corrosion resistance and fatigue resistance.

[0003] In the prior art, although conventional cast iron stoves have a high temperature tolerance, their surfaces are susceptible to high temperature oxidation and erosion by corrosive gases. Traditional coatings are mostly designed with a single material. Although these coatings can prevent corrosion to a certain extent, they cannot maintain long-term stability in high temperature environments. Especially under extreme temperature conditions, the coatings often crack, peel or oxidize, causing the stove surface to be exposed to the external environment, thereby accelerating the damage of the stove. In addition, traditional coatings have poor high temperature resistance and corrosion resistance, which can easily cause coating aging or damage, and cannot effectively prevent further damage to the stove material by melt or corrosive gases.

[0004] Furthermore, the multi-layer structure design of existing cast iron stove coatings is still immature, and many coating technologies fail to effectively solve the adhesion problem between the coating and the cast iron material in high-temperature environments, or fail to provide adequate protection under long-term high-temperature working conditions. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for processing a cast iron stove, which solves the problem that the existing cast iron stove has insufficient durability in a high temperature and high corrosion environment.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for processing cast iron stoves, comprising the following steps: S1. Selecting cast iron alloy material and preparing alloy by vacuum melting process; S2. Casting the alloy material into a cast iron furnace component; S3. Applying a coating on the surface of the cast iron stove; S4. Plasma spraying and laser surface treatment of the coating; S5. heat treating and cooling the cast iron furnace; S6. Assembling the treated cast iron stove to obtain the cast iron stove.

[0007] Preferably, the cast iron alloy material in step S1 includes a high chromium-molybdenum alloy, iron and a phase change alloy, the high chromium-molybdenum alloy has a chromium content of 15% to 25%, a molybdenum content of 5% to 10%, and the remainder is iron and unavoidable impurities, and the phase change alloy includes zirconium and titanium, the zirconium content is 1% to 2%, and the titanium content is 0.5% to 1.5%.

[0008] Preferably, the coating in step S3 includes a three-layer structure, namely a high temperature resistant base layer, a photocatalytic functional layer and a super hydrophobic corrosion resistant layer.

[0009] Preferably, the high temperature resistant base layer comprises tungsten and molybdenum, with the tungsten content being 55% to 65% and the molybdenum content being 35% to 45%.

[0010] Preferably, the photocatalytic functional layer comprises a composite material of TiO2, CeO2 and La2O3, wherein the content of TiO2 is 60% to 80%, the content of CeO2 is 10% to 20%, and the content of La2O3 is 5% to 10%.

[0011] Preferably, the super hydrophobic corrosion-resistant layer comprises a composite coating of aluminum fluoride and silicon dioxide, wherein the content of aluminum fluoride is 10% to 15% and the content of silicon dioxide is 70% to 85%.

[0012] Preferably, in the plasma spraying technology in step S4, the spraying temperature ranges from 500° C. to 1000° C., the spraying pressure ranges from 0.5 MPa to 1.0 MPa, and the coating thickness ranges from 50 µm to 200 µm.

[0013] Preferably, in the laser surface treatment in step S4, a laser power of 500 W to 800 W, a laser scanning speed of 1 mm / s to 5 mm / s, and a spot diameter of 0.5 mm to 2 mm are used.

[0014] Preferably, in step S5, the heat treatment temperature of the cast iron furnace is 900° C. to 1000° C., and the cooling rate is 1° C. / min to 5° C. / min.

[0015] Preferably, the final assembly of the cast iron stove in step S6 includes fixing the multiple cast iron components by welding or bolting.

[0016] The present invention provides a method for processing cast iron stoves, which has the following beneficial effects: 1. The present invention applies a three-layer coating on the surface of the cast iron stove, including a high temperature resistant base layer, a photocatalytic functional layer and a super hydrophobic corrosion resistant layer, to provide high temperature protection, photocatalytic decomposition of pollutants and anti-corrosion functions respectively. The layered design of the composite coating effectively prevents heat loss, enhances the corrosion resistance and self-cleaning function of the coating, not only reduces the accumulation of surface dirt, but also improves the anti-pollution property of the boiler surface, thereby improving the thermal efficiency and long-term operation stability of the stove.

[0017] 2. The present invention uses a composite material of high chromium-molybdenum alloy and phase change alloy, and accurately controls the alloy composition through a vacuum melting process, so that the alloy material maintains good chemical stability and high temperature resistance in a high temperature and high corrosion environment. In particular, the ratio of chromium and molybdenum is reasonably optimized during the melting process, and the phase change alloy of zirconium and titanium is combined to significantly improve the oxidation resistance and corrosion resistance of cast iron furnaces under long-term high temperatures, thereby extending the service life of cast iron furnaces and reducing equipment failures caused by material damage.

[0018] 3. The present invention uses plasma spraying technology and laser surface treatment to reinforce the coating to ensure the adhesion and stability of the coating. During the spraying process, the precisely controlled spraying temperature and pressure are used, combined with laser surface treatment, to make the coating evenly covered and enhance its wear resistance and high temperature oxidation resistance. This optimized coating process ensures that the coating can effectively protect the surface of the cast iron furnace for a long time in the environment of high temperature, corrosive gas and mechanical wear, thereby reducing the maintenance frequency and improving the reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the processing steps of the present invention. DETAILED DESCRIPTION

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

[0021] Please see attached Figure 1 The embodiment of the present invention provides a method for processing a cast iron stove, comprising the following steps: S1. Selecting cast iron alloy material and preparing alloy by vacuum melting process; Specifically, in the present invention, the first step is to select appropriate cast iron alloy materials and prepare the alloy through a vacuum melting process. This step plays a key role in the performance and structural stability of the entire cast iron stove. Especially in a high temperature and high corrosion environment, the selection and preparation process of the alloy directly determine the service life and reliability of the stove. Through precise material selection and optimized melting process, it can be ensured that the cast iron stove has excellent high temperature resistance and corrosion resistance.

[0022] Generally, the selected cast iron alloy materials contain two main components: high chromium-molybdenum alloy and phase change alloy. High chromium-molybdenum alloy is mainly used to improve the corrosion resistance of cast iron, especially in high-temperature working environment; while phase change alloy helps to improve the thermal stability and structural toughness of the material. Specifically, the proportion of these alloy components will be optimized according to the use conditions of the furnace to ensure that it can work stably for a long time in a high-temperature, highly corrosive gas environment.

[0023] In this embodiment, the chromium (Cr) content of the high chromium-molybdenum alloy is 15% to 25%, the molybdenum (Mo) content is 5% to 10%, and the iron (Fe) content is 80% to 85%. Through such alloy composition design, not only the oxidation resistance of the cast iron material is enhanced, but also its high temperature fatigue resistance can be improved. For example, chromium can effectively slow down the oxidation reaction by forming a chromium oxide film; molybdenum helps to improve the stability of the material at high temperature and avoid oxidation damage in a long-term high temperature environment.

[0024] As an option, the phase change alloy includes two elements, zirconium (Zr) and titanium (Ti), with the zirconium content ranging from 1% to 2% and the titanium content ranging from 0.5% to 1.5%. These elements can form a stable phase change structure at high temperatures in the alloy, and adjust the thermal expansion and thermal stability of the alloy through the phase change effect, further improving the furnace's tolerance to extreme temperature fluctuations.

[0025] The vacuum melting process is used to melt the high chromium-molybdenum alloy and the phase change alloy in the above proportion to ensure the uniform distribution of the alloy components. Vacuum melting can not only avoid the contamination of the alloy by impurities in the air, but also accurately control the amount of alloy elements added, further improving the purity and performance of the alloy.

[0026] The vacuum melting process generally includes the following steps: Put the selected alloy raw materials into the furnace according to proportion; The temperature and pressure are controlled by a vacuum environment to ensure that the elements in the alloy react fully and are evenly distributed under ideal conditions; During the smelting process, the temperature and pressure are monitored in real time to avoid unnecessary bubbles or impurities in the alloy.

[0027] In this process, the melting temperature is generally set at 1500℃ to 1700℃. During the melting process, electric arc furnaces or induction furnaces can be used to completely melt the raw alloy by heating. Through the vacuum environment, the content of oxygen, nitrogen and other elements in the alloy is effectively controlled, thereby preventing the oxidation reaction from affecting the properties of the alloy material.

[0028] The vacuum melting process lasts about 30 minutes to 2 hours, depending on the amount of alloy and the complexity of the alloy composition. During the melting process, the added molybdenum, chromium, zirconium, titanium and other elements fully react with the iron-based alloy in the furnace to form a uniform high-temperature alloy solution. Subsequently, through gradual cooling, the alloy components gradually solidify to form an alloy material suitable for cast iron furnace components.

[0029] The alloy material prepared by the above steps can ensure its stability and corrosion resistance in high temperature and high pressure environments. Specifically, during the use of the furnace, elements such as chromium and molybdenum can effectively enhance the high temperature oxidation resistance of the cast iron material, while zirconium and titanium can improve the thermal stability of the alloy and avoid thermal stress damage caused by long-term high temperature use.

[0030] It should be pointed out that the alloy ratio and element selection in the formula can be appropriately adjusted according to the different design requirements of the furnace in actual application to ensure that the best performance is maintained during the long-term high-temperature operation of the furnace.

[0031] S2. Casting the alloy material into cast iron furnace parts; Specifically, this step is closely related to the aforementioned step S1, because the alloy material selected in step S1 directly determines the performance of the alloy solution used in the casting process and the quality of the final casting. Through a reasonable casting process, it can be ensured that the alloy material uniformly fills the mold, and finally a cast iron component with the required mechanical properties and high temperature and corrosion resistance is formed.

[0032] Generally, after vacuum melting, cast iron alloy materials are temperature controlled and properly degassed to ensure that there are no bubbles or impurities in the alloy liquid, which is critical to the final quality of the casting. As the melting of the cast iron alloy is completed, the temperature of the alloy liquid usually needs to be maintained at a higher range, generally between 1500°C and 1700°C. This high temperature condition ensures that the alloy components are evenly mixed and provides sufficient fluidity to enable it to flow smoothly into the mold and fill every detail.

[0033] The cast iron alloy material is cast by precision casting or sand casting. Precision casting is usually suitable for castings with complex shapes and high precision, while sand casting has more cost advantages in mass production. For the cast iron stove parts of the present invention, sand casting is usually used, which has lower cost and higher production efficiency.

[0034] In this embodiment, the alloy liquid will be sent into the sand mold through the melting furnace, and the surface of the mold will undergo a series of treatments to improve the surface quality of the casting. In the casting process, the design of the mold is very important, especially to ensure that the alloy can quickly and evenly fill every detail after entering the mold to avoid casting defects such as cold shut or air holes.

[0035] As an option, the mold can be a single-use sand mold or a lost wax mold, depending on the complexity of the required casting and the production batch. In one possible implementation, lost wax casting technology is used, which can provide higher casting accuracy and more complex shapes, especially suitable for parts with small and complex structures in cast iron furnace parts.

[0036] Specifically, the alloy materials used in the casting process must first be degassed before casting to remove gases and impurities in the alloy liquid. This process usually involves passing the alloy liquid through a vacuum degassing furnace, where bubbles rise and are discharged through a vacuum environment, thereby preventing the formation of pores and inclusions and ensuring the mechanical properties of the casting. The degassing process requires the control of the degassing temperature, which is usually set at 1450°C to 1550°C to ensure that the alloy liquid reaches the optimal state for casting.

[0037] During this process, the temperature of the cast iron furnace mold and the alloy liquid needs to be strictly controlled to prevent the temperature from being too high or too low and affecting the fluidity of the alloy. The casting temperature usually needs to be controlled between 1550℃ and 1700℃ to ensure that the alloy liquid can be fully filled and quickly cooled into shape after entering the mold.

[0038] In some embodiments, other fluxing agents, such as aluminum or silicon, may be added during the casting process to improve the fluidity and lubricity of the alloy liquid. The addition of these elements can help the alloy flow into the mold better, reduce casting defects, and help improve the surface quality of the casting.

[0039] In addition, the size and shape design of cast iron furnace components need to be optimized according to actual use requirements. During the casting process, the mold design should ensure that the casting can shrink evenly during cooling to avoid stress concentration and deformation. Generally speaking, the mold design should also take into account the expansion coefficient of the metal to avoid the size change of the casting beyond the design range due to temperature changes.

[0040] S3. Applying coating on the surface of cast iron stove; Specifically, step S3 involves applying a coating on the surface of the cast iron furnace that has been vacuum melted and cast to enhance the performance of the furnace in high temperature and high corrosion environments. The application of the coating can not only significantly improve the high temperature resistance of the furnace, but also enhance its corrosion resistance and self-cleaning ability. This step is closely related to the aforementioned step S2. The aforementioned alloy casting step ensures the strength and toughness of the furnace matrix, and the application of the coating further improves its performance and durability.

[0041] Generally speaking, the surface coating of cast iron stoves is divided into multiple layers, and each layer plays a specific functional role. The coating usually includes a three-layer structure, namely a high-temperature resistant base layer, a photocatalytic functional layer, and a super-hydrophobic corrosion-resistant layer. Through this multi-layer structure, the different functions of the coating can be achieved, ensuring stability at high temperatures while improving corrosion resistance and self-cleaning capabilities.

[0042] In this embodiment, the first layer of the coating is a high temperature resistant base layer, the main function of which is to enhance the adhesion of the coating to the cast iron substrate and provide necessary high temperature protection. The high temperature resistant base layer is generally composed of tungsten (W) and molybdenum (Mo). Tungsten and molybdenum have very good stability at high temperatures and can effectively prevent thermal oxidation reactions. As an option, the tungsten content is 55% to 65%, and the molybdenum content is 45% to 60%. The proportions of these elements are adjusted according to the actual operating temperature range of the furnace to ensure the temperature resistance of the coating. Specifically, the high temperature stability of tungsten and molybdenum enables this layer of coating to effectively prevent the degradation of the material at high temperatures, especially when used for a long time in a high temperature environment, to avoid damage to the surface of the furnace.

[0043] In one possible implementation, the photocatalytic functional layer includes a composite material of TiO2 (titanium dioxide) and CeO2 (cerium dioxide) and La2O3 (cerium trioxide). TiO2 has excellent photocatalytic properties and can decompose organic matter such as dirt and oil stains attached to the surface of the stove under ultraviolet light. In addition, CeO2 and La2O3, as rare earth elements, play an enhancing role in the photocatalytic reaction and improve the photocatalytic efficiency of TiO2, especially under high temperature conditions. The content of TiO2 is usually 60% to 80%, the content of CeO2 is 10% to 20%, and the content of La2O3 is 5% to 10%. These component ratios help improve the stability and catalytic reaction efficiency of the coating at high temperatures and enhance its ability to decompose pollutants.

[0044] The super hydrophobic and corrosion-resistant layer is the last layer of the coating. Its main function is to improve the corrosion resistance of the furnace surface and also has a self-cleaning function. This layer is composed of a composite coating of aluminum fluoride (AlF3) and silicon dioxide (SiO2). Aluminum fluoride has excellent hydrophobicity and corrosion resistance, while silicon dioxide can enhance the wear resistance and stability of the coating. The content of aluminum fluoride is usually 10% to 15%, and the content of silicon dioxide is 70% to 85%. The function of this layer is to reduce the adhesion of moisture and dirt through super hydrophobicity, and at the same time, through the corrosion resistance of silicon dioxide, it prevents acidic gases or corrosive chemicals from damaging the surface of cast iron furnaces. This coating can not only prevent external corrosive substances from invading the furnace, but also maintain the cleanliness of the furnace surface during long-term high-temperature work, thereby reducing the frequency of manual cleaning and maintenance.

[0045] In some embodiments, the coating can be applied by plasma spraying technology. Plasma spraying technology can spray the coating evenly onto the surface of the cast iron stove under high temperature conditions to ensure good adhesion and uniformity of the coating. The spraying temperature is generally set at 500°C to 1000°C, the spraying pressure is 0.5MPa to 1.0MPa, and the coating thickness is controlled between 50µm and 200µm. During the spraying process, the plasma spray gun generates high-temperature plasma through an electric arc, heats the coating particles to a molten state, and sprays them onto the surface of the cast iron stove, which is quickly cooled to form a solid coating.

[0046] In another possible implementation, the coating can be further enhanced through laser surface treatment. Laser surface treatment can precisely control the thickness and density of the coating. By irradiating the coating surface with a laser beam, the microstructure of the coating is changed, thereby improving its wear resistance and oxidation resistance. The laser power is usually set to 200W to 1000W, the laser scanning speed is 1mm / s to 5mm / s, and the spot diameter is controlled between 0.5mm and 2mm. Through this process, the microstructure of the coating is further optimized, enhancing the stability and service life of the coating.

[0047] S4. Plasma spraying and laser surface treatment of the coating; Specifically, step S4 involves plasma spraying and laser surface treatment of the coating. The application and post-treatment process of the coating is an important step to ensure that the surface of the cast iron stove has the required functional properties, including high temperature resistance, corrosion resistance and self-cleaning properties. In the above step S3, the coating structure is reasonably designed and applied to the surface of the cast iron stove, while step S4 is mainly responsible for enhancing the adhesion between the coating and the substrate and improving the stability and wear resistance of the coating.

[0048] Generally speaking, plasma spraying and laser surface treatment are two common surface strengthening technologies. The two complement each other and can maximize the performance of the coating. Plasma spraying technology heats the coating material to a molten state through high-temperature plasma and sprays it onto the surface of the cast iron stove to form a uniform and dense coating. Laser surface treatment uses the high energy density of the laser beam to form microstructural changes on the coating surface, further enhancing the adhesion, wear resistance and high-temperature oxidation resistance of the coating.

[0049] In this embodiment, plasma spraying technology is used for the preliminary application of the coating. By feeding a suitable spray powder (e.g., a composite coating containing tungsten, molybdenum, TiO2, CeO2, etc.) into a high-temperature plasma for heating, the coating powder is melted and quickly sprayed onto the surface of the cast iron stove. During the spraying process, the spray gun controls the temperature and pressure so that the coating is evenly covered on the surface of the stove. Specifically, the spraying temperature is controlled between 500°C and 1000°C, the spraying pressure is 0.5MPa to 1.0MPa, and the coating thickness is generally set between 50μm and 200μm. By controlling these parameters, good adhesion between the coating and the cast iron substrate is ensured, and the high temperature resistance and corrosion resistance of the coating are improved.

[0050] As an option, the coating powder used in the spraying process can be a composite material containing titanium dioxide (TiO2) and rare earth oxides (such as CeO2, La2O3). This composite material has good photocatalytic properties and can promote the decomposition of pollutants on the coating surface under ultraviolet light, thereby improving the self-cleaning performance of the stove.

[0051] In step S4, laser surface treatment further enhances the performance of the coating. During the laser surface treatment process, the laser beam irradiates the coating surface with a certain power density, causing the coating to be rapidly heated to a high temperature in a local area, causing the microstructure of the coating to change. Through this process, the density of the coating surface can be improved, and its wear resistance, corrosion resistance and high temperature stability can be further enhanced.

[0052] Specifically, the laser power is usually set to 200W to 1000W, the laser scanning speed is 1mm / s to 5mm / s, and the spot diameter is controlled between 0.5mm and 2mm. Through precise laser scanning, a uniform microstructure with excellent performance can be formed on the coating surface. This treatment can not only enhance the adhesion of the coating, but also improve the thermal stability of the coating, ensuring that it can maintain stable performance for a long time in a high temperature environment.

[0053] In one possible implementation, laser surface treatment is not only used to strengthen the coating, but also to repair minor defects on the coating surface. Through high energy density irradiation of the laser beam, the coating can be re-melted in a local area on the coating surface, thereby eliminating possible microcracks or pores, further improving the overall quality and service life of the coating.

[0054] S5. heat treating and cooling the cast iron furnace; Specifically, this step is closely related to the aforementioned S4 step. The aforementioned coating treatment process has enhanced the high temperature resistance and corrosion resistance of the surface of the cast iron furnace, while the heat treatment process ensures the optimization of the overall performance of the cast iron parts. Heat treatment not only helps to improve the hardness of cast iron, but also optimizes its microstructure, thereby improving the stability and fatigue resistance of cast iron parts under high temperature and high pressure conditions.

[0055] Generally speaking, the heat treatment process of cast iron furnaces includes two main steps: heating to a predetermined temperature, maintaining a certain time to promote grain growth, transformation and stress release in the alloy, and then cooling. The control of heat treatment temperature and cooling rate is very important, as they directly affect the mechanical properties, corrosion resistance and long-term stability of cast iron.

[0056] In this embodiment, the heat treatment temperature of the cast iron furnace is generally set between 800°C and 1000°C, and the specific temperature depends on the alloy composition used and the expected use environment of the furnace. Higher temperatures help the grains in the alloy to undergo appropriate changes, improving the overall toughness and fatigue resistance of the cast iron. The heating process usually lasts 1 to 2 hours to ensure that the alloy material is evenly heated throughout the volume and achieves the predetermined heat treatment effect.

[0057] As an option, the temperature during heat treatment can be fine-tuned according to the chemical composition of the cast iron and the application requirements. For example, in some cases, if a highly corrosion-resistant alloy with more alloying elements is used, it may be necessary to slightly increase the heat treatment temperature to further optimize the solubility and distribution of the alloying elements, thereby improving the material's corrosion resistance.

[0058] Specifically, during the heat treatment process, the furnace needs to be heated evenly and maintained at the target temperature to promote the transformation of the crystal structure of the cast iron alloy and reduce internal stress. This process helps to improve the organizational structure of the cast iron material, enhance its mechanical properties at high temperatures, and ensure its stability in long-term high-temperature use. The surface of the cast iron furnace after heat treatment will show better oxidation resistance and corrosion resistance, laying the foundation for subsequent long-term use.

[0059] After the heat treatment is completed, the cooling process is a key step to ensure that the cast iron furnace achieves optimal performance. The control of the cooling rate is crucial to the final properties of the cast iron material. Generally speaking, the cooling rate of the cast iron furnace is usually set between 1℃ / min and 5℃ / min. Too fast cooling process may cause excessive internal stress inside the cast iron or cause uneven solidification, which may lead to cracks or deformation of the cast iron parts. Too slow cooling may cause the grains to be too large, affecting the strength and toughness of the cast iron.

[0060] In one possible implementation, water cooling or air cooling can be used during the cooling process, and the specific choice depends on the size of the cast iron furnace and the cooling requirements. For larger cast iron parts, air cooling can be used to ensure a more stable temperature change; for smaller parts, water cooling can be used to speed up the cooling speed, ensuring that the cast iron parts reach the required hardness and strength in a shorter time.

[0061] During the cooling process, the phase transformation and crystallization process of the alloy will further improve the mechanical properties of the material. In particular, during the grain refinement process, the hardness and compressive strength of the cast iron are improved. Through the precise control of the cooling rate and the heat treatment temperature, the present invention can ensure that the cast iron stove has excellent fatigue resistance, high temperature stability and high corrosion resistance, so that it can maintain stable performance for a long time in a high temperature working environment.

[0062] S6. Assembling the treated cast iron stove to obtain the cast iron stove.

[0063] Specifically, in general, the assembly process of cast iron stoves involves splicing multiple separately manufactured parts such as the furnace body, furnace door, furnace cover, external support, etc. according to the design requirements. Each component must ensure mutual matching and firmness of connection during the assembly process to avoid failures caused by looseness or structural instability in actual use. Therefore, during assembly, in addition to strict inspection of the size and surface quality of each component, special attention must be paid to the bearing capacity and durability of the connection parts.

[0064] In this embodiment, the assembly of the cast iron stove includes fixing a plurality of cast iron parts by welding or bolting. Specifically, welding is generally suitable for connecting parts that need to withstand large mechanical stress or thermal stress, while bolting is suitable for parts that can be mechanically fixed without being affected by excessive thermal stress. The selection of the two connection methods is optimized according to the specific stove design and the actual use environment.

[0065] In some embodiments, the welding method is mainly used for connecting the main structural components of the furnace body. Generally, the specific welding method can be selected from gas shielded welding, arc welding or argon arc welding, etc. These methods can provide high-strength connection effects and ensure close bonding between cast iron parts. During the welding process, the temperature and speed of the welding area need to be strictly controlled to avoid overheating or stress concentration in the welding area, and prevent cracks or deformation caused by welding.

[0066] As an option, some parts can be connected by bolts. Bolt connections provide convenient disassembly and maintenance functions, especially for parts that need to be inspected or replaced regularly. In this case, the material and size of the bolts need to be reasonably selected according to the thickness and service strength of the cast iron parts. Generally speaking, the strength of the bolts should be able to withstand the working load of the cast iron stove at high temperature and prevent loosening due to vibration or thermal expansion during use.

[0067] In actual operation, the sealing of each connection point during the assembly process is also very important. Specifically, the connection points need to ensure good sealing to prevent gas leakage or heat loss problems when the furnace is working at high temperatures. Therefore, when making bolt connections, materials such as sealing gaskets or thermosetting adhesives are usually used for additional sealing to ensure the air tightness and heat tightness of the connection points.

[0068] The following is an introduction in conjunction with specific embodiments: Example 1: Preparation of high temperature corrosion resistant cast iron stove This embodiment provides a method for preparing a high-temperature corrosion-resistant cast iron stove. The method solves the problem of cast iron stoves being susceptible to oxidation and corrosion in high-temperature and high-corrosion environments mentioned in the background art by selecting specific alloy materials and combining advanced coating technology and heat treatment processes.

[0069] Step 1: Selection and preparation of alloy materials First, high chromium-molybdenum alloy and phase change alloy are selected as the main alloy materials. Specifically, the chromium (Cr) content in the alloy is 18%, the molybdenum (Mo) content is 7%, and the iron (Fe) content is 76%. In order to ensure the corrosion resistance of the alloy, 1.5% zirconium (Zr) and 0.8% titanium (Ti) are also added. The alloy is prepared by a vacuum melting process, and the melting temperature is set to 1600°C. During the melting process, vacuum degassing is used to remove bubbles and impurities in the alloy to ensure the uniformity and purity of the alloy.

[0070] Step 2: Casting After the alloy is melted, it is poured into a sand mold to complete the molding of the cast iron furnace parts. During the casting process, the casting temperature is controlled at 1550℃ and maintained at this temperature for 5 minutes to ensure the quality of the casting. During the cooling process, the cooling rate is controlled at 2℃ / min to avoid cracks or stress concentration on the cast iron surface due to rapid cooling.

[0071] Step 3: Coating Application A multi-layer coating is applied to the surface of the casting. First, a tungsten-molybdenum-based high-temperature resistant base layer is applied, which has a tungsten content of 60% and a molybdenum content of 40%. Then, a photocatalytic functional layer containing TiO2, CeO2, and La2O3 is coated thereon, with a TiO2 ratio of 70%, CeO2 of 15%, and La2O3 of 10%. Finally, a super-hydrophobic corrosion-resistant layer is applied, using a composite coating of aluminum fluoride (AlF3) and silicon dioxide (SiO2), with an aluminum fluoride content of 12% and a silicon dioxide content of 75%. The coating is applied by plasma spraying technology, with the spraying temperature controlled at 950°C, the spraying pressure of 0.8MPa, and the coating thickness of 150µm.

[0072] Step 4: Laser Surface Treatment The coating surface is laser treated with a laser power of 800W, a scanning speed of 2mm / s, and a spot diameter of 1mm. Through laser treatment, the adhesion and density of the coating are further enhanced, and the wear resistance and high temperature oxidation resistance of the coating are improved.

[0073] Step 5: Heat Treatment and Cooling After the cast iron furnace is coated, it is heat treated. The heat treatment temperature is set at 900℃, maintained for 1 hour, and the cooling rate is 2℃ / min. The heat treatment process optimizes the microstructure of the cast iron and enhances its oxidation resistance and corrosion resistance. After the heat treatment, the cast iron furnace is placed in the air to cool naturally.

[0074] Step 6: Assembly The various parts of the cast iron stove are fixed by bolting. The torque of all bolts is strictly controlled according to the design standards to ensure the stability of the connection. The joints are sealed with sealing gaskets to ensure that there is no gas leakage or heat loss.

[0075] Example 2: Preparation of cast iron furnace under high temperature and high pressure environment This embodiment is aimed at cast iron stoves in high temperature and high pressure environments, and focuses on solving the structural stability and corrosion resistance of cast iron stove components at high temperatures. By adopting special cast iron alloys and multi-layer coating processes, the long-term stability of cast iron stoves under extreme conditions is significantly improved.

[0076] Step 1: Selection and preparation of alloy materials High chromium-molybdenum alloy and phase change alloy are selected, with chromium (Cr) content of 20%, molybdenum (Mo) content of 8%, and iron (Fe) accounting for 72%. 2% titanium (Ti) and 1% zirconium (Zr) are added to improve high temperature performance and thermal stability. The alloy is smelted in an electric arc furnace with a temperature controlled at 1700°C to ensure uniform distribution and high purity of each element in the alloy.

[0077] Step 2: Casting The molten alloy liquid is poured into the sand mold, and the pouring temperature is controlled at 1580℃ to ensure good fluidity of the alloy. The design of the mold allows the alloy to quickly fill each detail to avoid pores or uneven cooling. The cooling rate is set at 1.5℃ / min to ensure that the cast iron surface is flat and crack-free.

[0078] Step 3: Coating Application After the casting is cooled, three layers of functional coating are applied. First, a high-temperature resistant base layer is applied, with tungsten (W) and molybdenum (Mo) in a ratio of 50% and 50% to ensure the stability of the coating at high temperatures. Secondly, a photocatalytic functional layer is applied, consisting of TiO2 (65%), CeO2 (20%) and La2O3 (15%), to improve the self-cleaning ability of the furnace surface. Finally, a superhydrophobic corrosion-resistant layer is applied, which is a composite of aluminum fluoride (AlF3) and silicon dioxide (SiO2), with an aluminum fluoride ratio of 10% and a SiO2 ratio of 80%. The coating is applied by plasma spraying technology, with the spraying temperature controlled at 900°C, the spraying pressure of 1.0MPa, and the coating thickness of 120µm.

[0079] Step 4: Laser Surface Treatment The coating was subjected to laser surface treatment with a laser power of 500W, a scanning speed of 3mm / s, and a spot diameter of 1mm. Laser treatment not only enhanced the adhesion of the coating, but also improved the thermal stability and corrosion resistance of the coating by changing the microstructure.

[0080] Step 5: Heat Treatment and Cooling After the coating treatment is completed, heat treatment is carried out, and the heat treatment temperature is set to 950℃ and the holding time is 1 hour. During the cooling process, a combination of air cooling and water cooling is used, and the cooling rate is controlled at 2℃ / min to ensure that the hardness and strength of the cast iron parts are improved.

[0081] Step 6: Assembly The various components are connected together by welding and bolting. The welding area adopts argon arc welding, which has high welding strength and can withstand high temperature and mechanical stress. Bolt connection is mainly used to fix the furnace door and furnace body to ensure the sealing of various components of the furnace.

[0082] Example 3: Preparation of highly wear-resistant cast iron stove This embodiment aims at preparing highly wear-resistant cast iron stoves, and solves the problem of poor surface wear resistance of cast iron stoves in high-temperature operating environments. By adopting a special coating process, the wear resistance of the cast iron stoves during use is greatly improved.

[0083] Step 1: Selection and preparation of alloy materials A high chromium-molybdenum alloy is selected, with a chromium (Cr) content of 22%, a molybdenum (Mo) content of 6%, and an iron (Fe) content of 72%. In order to improve the wear resistance of cast iron, 1% titanium (Ti) and 1.5% manganese (Mn) are also added to the alloy. The alloy is melted in an electric arc furnace at a melting temperature of 1650°C. After melting, the alloy liquid is finely adjusted to ensure the uniformity of the alloy.

[0084] Step 2: Casting After the alloy is melted, it is poured into the precision casting mold, and the pouring temperature is set to 1560℃. Through the precision casting process, the surface quality of the cast iron furnace is effectively controlled. The temperature during the cooling process is controlled at 2℃ / min to ensure that there are no cracks or surface defects in the casting during the cooling process.

[0085] Step 3: Coating Application The coating is applied with a tungsten-molybdenum-based high-temperature resistant base layer and a photocatalytic functional layer. The photocatalytic layer uses TiO2TiO2TiO2 and CeO2, with contents of 70% and 30% respectively. In addition, a super-hydrophobic corrosion-resistant layer is applied to the surface of the coating, mainly using aluminum fluoride and silicon dioxide, with the proportion of aluminum fluoride being 10% and the proportion of silicon dioxide being 80%. The coating is applied by plasma spraying technology, with a spraying temperature of 950°C, a spraying pressure of 1.2MPa, and a coating thickness of 200µm.

[0086] Step 4: Laser Surface Treatment After the coating is completed, laser surface treatment is carried out, with a laser power of 1000W, a spot diameter of 1.5mm, and a laser scanning speed of 4mm / s. Laser treatment not only strengthens the bonding force between the coating and the substrate, but also improves the wear resistance of the coating and significantly increases the hardness of the furnace surface.

[0087] Step 5: Heat Treatment and Cooling The heat treatment process is controlled at 950℃ for 1 hour to ensure the uniformity of the alloy and the stability of the coating. During the cooling process, the cooling rate is 3℃ / min to ensure that the surface hardness of the cast iron meets the requirements.

[0088] Step 6: Assembly Finally, the cast iron stove components are assembled by bolting to ensure a stable structure. Sealing gaskets are used at all joints to prevent gas leakage.

[0089] Comparative Example 1: Comparison between traditional cast iron stove and cast iron stove of the present invention In Comparative Example 1, a conventional cast iron stove and the cast iron stove of the present invention are compared, with the focus on the selection of alloy materials and coating process. Conventional cast iron stoves usually use simple carbon steel or ordinary cast iron alloys, while the present invention uses a composite material of high chromium-molybdenum alloy and phase change alloy, and adds multiple functional layers to the surface coating, which significantly improves the high temperature resistance and corrosion resistance of the stove.

[0090] Prior art (comparative example): In the prior art, the alloy materials of cast iron stoves are generally composed of ordinary cast iron or low alloy steel. The chemical composition of these alloys is mainly iron and a small amount of carbon, and the common ratio is: Iron (Fe): 95% to 98%; Carbon (C): 2% to 3%; Small amounts of impurity elements such as silicon, manganese, phosphorus, and sulfur.

[0091] This type of cast iron material is usually prone to oxidation corrosion at high temperatures, and dirt is easily accumulated on the surface, affecting the thermal efficiency and service life of the furnace. In order to improve the surface corrosion resistance, a single coating treatment technology is often used, such as spraying or painting, but the effect of these coatings is often not long-lasting and is easy to fall off under high temperature conditions.

[0092] Comparative example process flow: Select conventional alloy materials (iron and carbon alloy) and adopt sand casting process for casting.

[0093] The alloy liquid temperature is controlled at 1550°C.

[0094] After casting, the cast iron parts do not need to undergo complicated coating treatment. Only conventional spraying process is used to treat the furnace surface. The spraying thickness is usually 50µm to 100µm, and the spraying material is ordinary high-temperature paint.

[0095] After spraying, a simple heat treatment is performed, the heat treatment temperature is set at 800°C to 900°C, and the cooling rate is 1°C / min.

[0096] Then it is directly assembled, and the connection method is conventional bolt connection or welding connection.

[0097] Comparative Example 2: Comparison between a single-layer coating and a multi-layer coating of the present invention The difference between this embodiment and comparative example 2 lies in the structural design of the coating. The surface of the cast iron stove of the present invention adopts a three-layer composite coating technology, while the traditional cast iron stove usually uses a single coating, such as a single-layer anti-corrosion coating. Although the traditional coating process can provide a certain degree of corrosion resistance, it does not take into account the self-cleaning performance and durability under high temperature working conditions, resulting in poor coating effect and easy degradation.

[0098] Prior art (comparative example): The surface of traditional cast iron stoves is generally only coated with a single layer of anti-corrosion coating. This coating is usually a high-temperature corrosion-resistant coating, mainly composed of organic or inorganic components. Common coating components are: Inorganic coatings (such as aluminum chloride, aluminum oxide) or organic resins.

[0099] The coating thickness is usually 50µm to 100µm and the coating is applied by spraying or brushing. The main function of the coating is to improve the corrosion resistance of the cast iron surface and protect the furnace surface from thermal damage and chemical attack.

[0100] Comparative example process flow: The alloy material is prepared by a conventional vacuum melting process.

[0101] The casting process adopts sand casting or similar traditional casting methods.

[0102] After casting, the furnace surface is coated with a single layer of anti-corrosion coating. The coating material is a composite coating containing aluminum chloride and aluminum oxide. The spraying temperature is 900°C and the spraying thickness is 50µm to 100µm.

[0103] After the coating is dried, a simple heat treatment is performed at a temperature of 800°C and a cooling rate of 2°C / min.

[0104] The stove components are then assembled by bolting.

[0105] Comparative Example 3: Comparison between the traditional coating process and the laser processing process of the present invention Compared with the traditional coating treatment in Comparative Example 3, the coating treatment in this embodiment adopts the advanced process of laser surface treatment. Traditional cast iron stove coating treatment is mostly spraying or brushing, the coating quality is difficult to control, and lacks efficient microstructure strengthening. The present invention further enhances the stability and high temperature resistance of the coating through laser treatment, ensuring the long-term reliable operation of the stove in a high temperature environment.

[0106] Prior art (comparative example): In the prior art, conventional spraying technology is usually used for coating treatment. Although spraying can improve the corrosion resistance and high temperature stability of the cast iron surface to a certain extent, due to the lack of effective post-treatment process, the coating is easy to fall off or degrade under high temperature conditions.

[0107] Comparative example process flow: Conventional cast iron alloy materials are selected and the alloy is prepared by vacuum melting.

[0108] The casting process adopts sand casting, and the surface of the cast iron parts is sprayed with a coating thickness of 50µm to 100µm.

[0109] The coating is evenly sprayed onto the surface of the cast iron using a conventional spraying process, and the commonly used coating composition is an inorganic coating containing aluminum chloride.

[0110] After spraying, a simple heat treatment is carried out, the heat treatment temperature is set to 800°C, and the cooling rate is 2°C / min.

[0111] Finally, the stove components are fixed by bolting.

[0112] Experimental Design 1: High Temperature Corrosion Resistance Comparison Experiment This experiment aims to compare the durability of cast iron stoves in the present invention and the comparative example under high temperature and high corrosion environment, especially the high temperature oxidation resistance and corrosion resistance of the surface coating. Through this experiment, it can be verified that the coating process and alloy materials of the present invention have advantages over traditional technologies under extreme conditions.

[0113] 1. Experimental purpose: The corrosion resistance and high temperature oxidation resistance of the cast iron stove of the present invention in a high temperature and high corrosion environment were verified, and compared with the conventional technology (comparative example).

[0114] 2. Experimental materials: Embodiment 1 (embodiment of the present invention): A high chromium-molybdenum alloy (chromium content of 18%, molybdenum content of 7%, iron content of 76%) is used, and a three-layer composite coating (high temperature resistant base layer, photocatalytic functional layer, super hydrophobic corrosion resistant layer) is used.

[0115] Comparative Example 1: Using traditional cast iron material (iron content 95% to 98%, carbon content 2% to 3%), a single layer of anti-corrosion coating is applied on the surface.

[0116] 3. Experimental methods: Temperature setting: The experimental equipment is a high temperature test furnace, the temperature is set to 900℃ and maintained for 48 hours. Samples are taken out every 12 hours for surface inspection.

[0117] Corrosive environment: Add high-concentration chloride solution (such as NaCl solution) into the furnace to simulate a highly corrosive environment, and continuously apply a corrosive gas environment (such as SO2, HCl mixed gas).

[0118] Experimental comparison: The cast iron stove components in Example 1 and Comparative Example 1 were placed in the furnace respectively.

[0119] Under high temperature conditions, measure the thickness of the oxide layer on the surface of the stove and whether the coating is falling off or discolored.

[0120] Surface changes were recorded every 24 hours to test corrosion rate and coating damage.

[0121] 4. Experimental setup: Sample preparation: Each stove sample in the embodiment and the comparative example has the same size (10 cm×10 cm), and the number of samples is 3 for each, and three groups of comparative experiments are carried out.

[0122] Measurement method: Use electron scanning microscope and energy spectrum analyzer to detect the composition and thickness of the oxide layer on the surface of the sample.

[0123] High temperature corrosion comparison test data table: Experimental summary and mechanism analysis: In this experiment, the cast iron stove of Example 1 showed significantly better high temperature oxidation resistance and corrosion resistance than that of Comparative Example 1. Through the high temperature corrosion experiment, it can be seen that in a high temperature environment of 900°C, the three-layer coating of Example 1 always maintains good integrity, with less accumulation of oxidation layer and corrosion layer, while the single-layer coating of Comparative Example 1 has large-scale peeling and severe oxidation reaction in a short time. This result verifies the significant effect of the composite coating technology adopted by the present invention in improving high temperature stability and corrosion resistance.

[0124] From a mechanistic point of view, the multi-layer coating structure of the present invention can effectively block the erosion of high temperature and corrosive gases. The first layer of the coating, the high temperature resistant base layer, mainly reduces the oxidation reaction through the high temperature stability of tungsten and molybdenum, while the second layer of the photocatalytic functional layer decomposes pollutants through photocatalysis, reducing the accumulation of surface pollution. Finally, the super hydrophobic corrosion-resistant layer not only improves the corrosion resistance of the stove surface through the combination of aluminum fluoride and silicon dioxide, but also reduces the adhesion of moisture and dirt through super hydrophobicity, preventing the accumulation of surface corrosive substances. The design of this multi-layer structure solves the problem of degradation of traditional coatings in high temperature and corrosive environments.

[0125] Compared with the traditional single-layer coating technology, the coating of the present invention provides more comprehensive protection. In traditional cast iron stoves, the single-layer coating is easy to fail at high temperature, the oxide layer thickens rapidly, and the coating is easy to peel off. However, the present invention adopts a combination of a high-temperature resistant base layer, a photocatalytic functional layer and a super-hydrophobic corrosion-resistant layer, which can maintain the integrity of the coating and effectively reduce the peeling of the coating under the dual effects of high temperature and corrosive gas.

[0126] In addition, the experimental data also show that in a high temperature environment, the accumulation of the corrosion layer on the surface of the cast iron stove of Example 1 is less, and the coating exhibits stronger durability, and the ability to resist high temperature oxidation is much better than that of Comparative Example 1. This shows that the cast iron stove of Example 1 performs more stably in long-term high temperature operation, which not only prolongs the service life of the stove, but also significantly reduces the maintenance cost.

[0127] Experimental Design 2: Mechanical Strength and Thermal Stability Comparison Experiment The purpose of this experiment is to compare the mechanical strength and thermal stability of the cast iron stove of the present invention and the cast iron stove of the comparative example at high temperature. Through this experiment, the structural stability, fatigue resistance and performance of the cast iron stove of the present invention under long-term high temperature operation are verified.

[0128] 1. Experimental purpose: The mechanical strength, fatigue resistance and thermal stability of the cast iron stove of the present invention and the comparative example at high temperature were compared to evaluate the reliability of long-term use.

[0129] 2. Experimental materials: Embodiment 2 (embodiment of the present invention): using high chromium-molybdenum alloy and phase change alloy, the coating includes a high temperature resistant base layer, a photocatalytic functional layer and a super hydrophobic corrosion resistant layer.

[0130] Comparative Example 2: Traditional cast iron stove, the coating is a single-layer anti-corrosion coating.

[0131] 3. Experimental methods: High temperature tensile test: The cast iron stove samples in the embodiment and the comparative example were placed in a high temperature furnace at 1000° C. and subjected to tensile tests to test their tensile strength, elongation and fracture position.

[0132] Experimental equipment: Use a high temperature tensile testing machine with a loading speed of 2 mm / min.

[0133] Measurement indicators: record the maximum tensile strength, elongation and fracture mode (brittle fracture or ductile fracture) of the sample.

[0134] Thermal stability test: Heat the sample at 1000℃ for 12 hours, and check the deformation of the cast iron stove after cooling. Record the volume change of the stove at high temperature, and check the peeling and cracking of the surface coating.

[0135] 4. Experimental comparison: Compare the samples in Example 2 and Comparative Example 2, and record the strength reduction and deformation of each stove under high temperature conditions.

[0136] For Example 2, it is expected that the coating and the alloy material will maintain high strength and thermal stability, while the coating of Comparative Example 2 may fall off or crack, resulting in a decrease in strength.

[0137] 5. Experimental setup: Sample preparation: Three samples (each with a size of 10 cm×10 cm) were used in each set of experiments, and the embodiments and comparative examples were compared respectively.

[0138] Measurement method: Use an electronic tensile testing machine and a high-temperature constant temperature furnace to perform tensile tests, and use a digital microscope and high-temperature measuring equipment to record deformation and surface changes.

[0139] Tensile strength and thermal stability comparison test data table: Experimental summary and mechanism analysis: From the experimental results, the cast iron stove with high chromium-molybdenum alloy and three-layer coating of the present invention performs significantly better than traditional cast iron stoves in high temperature environment. In Example 3, the coating did not peel off or crack on a large scale, and the cast iron parts maintained high tensile strength and elongation, while the coating of Comparative Example 3 degraded rapidly at high temperature, cracked and peeled off, resulting in a significant decrease in its mechanical properties. By comparison, it can be seen that the cast iron stove of the present invention has better comprehensive performance in high temperature resistance and corrosion resistance than the prior art, significantly improving the long-term service life of the cast iron stove.

[0140] Mechanistically, the three-layer coating structure of the present invention plays a multiple protective role. The first layer of the high temperature resistant base layer, composed of tungsten and molybdenum, can effectively block high temperature oxidation and reduce the formation of an oxide layer on the surface of the stove. The second layer of the photocatalytic functional layer, mainly composed of materials such as TiO2, CeO2, La2O3, etc., can catalyze reactions at high temperatures, decompose attached organic matter, reduce the accumulation of pollutants on the stove, and further improve its corrosion resistance. Finally, the super hydrophobic corrosion-resistant layer enhances the corrosion resistance of the surface through the combination of aluminum fluoride and silicon dioxide, and reduces the erosion of moisture and chemicals on the surface coating.

[0141] Compared with traditional single-layer coatings, the multi-layer coating of the present invention can not only provide better protection in extreme environments, but also maintain good structural stability at high temperatures, avoiding coating peeling and cracks caused by thermal stress. This design can also effectively improve the fatigue resistance of cast iron stoves and avoid the degradation of traditional coatings under high temperature.

[0142] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for processing cast iron stoves, characterized in that: The following steps are involved: S1. Selecting cast iron alloy material and preparing alloy by vacuum melting process; S2. Casting the alloy material into a cast iron furnace component; S3. Applying a coating on the surface of the cast iron stove; S4. Plasma spraying and laser surface treatment of the coating; S5. heat treating and cooling the cast iron furnace; S6. Assembling the treated cast iron stove to obtain the cast iron stove.

2. The method for processing a cast iron stove according to claim 1, characterized in that: The cast iron alloy material in S1 includes a high chromium-molybdenum alloy, iron and a phase change alloy. The high chromium-molybdenum alloy has a chromium content of 15% to 25%, a molybdenum content of 5% to 10%, and the remainder is iron and inevitable impurities. The phase change alloy includes zirconium and titanium, with a zirconium content of 1% to 2% and a titanium content of 0.5% to 1.5%.

3. The method for processing a cast iron stove according to claim 1, characterized in that: The S3 coating includes a three-layer structure, namely a high temperature resistant base layer, a photocatalytic functional layer and a super hydrophobic corrosion resistant layer.

4. The method for processing a cast iron stove according to claim 3, characterized in that: The high temperature resistant base layer comprises tungsten and molybdenum, wherein the content of tungsten is 55% to 65% and the content of molybdenum is 35% to 45%.

5. The method for processing a cast iron stove according to claim 3, characterized in that: The photocatalytic functional layer comprises a composite material of TiO2, CeO2 and La2O3, wherein the content of TiO2 is 60% to 80%, the content of CeO2 is 10% to 20%, and the content of La2O3 is 5% to 10%.

6. The method for processing a cast iron stove according to claim 3, characterized in that: The super hydrophobic corrosion-resistant layer comprises a composite coating of aluminum fluoride and silicon dioxide, wherein the content of aluminum fluoride is 10% to 15% and the content of silicon dioxide is 70% to 85%.

7. The method for processing a cast iron stove according to claim 1, characterized in that: The S4 plasma spraying technology has a spraying temperature range of 500°C to 1000°C, a spraying pressure of 0.5MPa to 1.0MPa, and a coating thickness of 50µm to 200µm.

8. The method for processing a cast iron stove according to claim 1, characterized in that: The laser surface treatment in S4 adopts a laser power of 500W to 800W, a laser scanning speed of 1mm / s to 5mm / s, and a spot diameter of 0.5mm to 2mm.

9. The method for processing a cast iron stove according to claim 1, characterized in that: The heat treatment temperature of the cast iron furnace in S5 is 900° C. to 1000° C., and the cooling rate is 1° C. / min to 5° C. / min.

10. The method for processing cast iron stove according to claim 1, characterized in that: The final assembly of the cast iron stove in S6 includes fixing the multiple cast iron parts by welding or bolting.

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