A casting process for high-efficiency investment casting of rotary kiln half gear ring castings

Abstract

The present invention discloses a casting process for a high-efficiency investment casting rotary kiln half-gear ring casting, which relates to the technical field of investment casting, and includes the following steps: S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing. The present invention uses advanced smelting equipment and pure metal raw materials in the metal smelting process, selects pure metal iron blocks and refined carbon-nickel alloys as raw materials to reduce the impurity content in the raw materials, uses a vacuum smelting furnace for hot melting to improve the purity and quality of the molten metal, and accurately controls the smelting temperature and time of the metal iron blocks and refined carbon-nickel alloys to avoid excessive oxidation of the molten metal or the generation of other impurities, reduce casting defects, reduce production costs and energy consumption, and improve the efficiency and quality of the rotary kiln half-gear ring investment casting process.

Description

Technical Field

[0001] The invention relates to the technical field of investment casting, in particular to a casting process for a high-efficiency investment casting rotary kiln half gear ring casting. Background Art

[0002] The rotary kiln half gear ring casting is one of the key components of the rotary kiln. It is a steel casting. The rotary kiln half gear ring casting is generally divided into two half gear rings. High-efficiency investment casting is a precision casting method, which is suitable for manufacturing castings with complex shapes, precise dimensions and smooth surfaces. For large and complex castings such as rotary kiln half gear ring castings, the use of high-efficiency investment casting technology can ensure the quality and precision of the castings.

[0003] The defects of the investment casting process in the prior art are:

[0004] 1. Patent document US6769475B2 discloses an investment casting method, which uses traditional smelting equipment and cannot guarantee the purity and quality of molten metal, resulting in casting defects.

[0005] 2. Patent document CN111922286B discloses an investment casting material and an investment casting method. The investment casting method cannot remove oxygen and impurities in the molten metal during the vacuum melting process, which easily causes defects such as shrinkage cavities and looseness of the molten metal after shaping, and cannot guarantee the density and mechanical properties of the casting after pouring.

[0006] 3. Patent document CN109894575B discloses a process for producing investment casting cores for turbocharger volutes and pump parts. The investment casting process uses paraffin raw materials to prepare wax patterns. Paraffin has a large shrinkage rate and is prone to cracks and deformation, making it impossible to ensure the stability of subsequent processing of investment casting.

[0007] 4. Patent document CN115338370A discloses an investment casting process for a duplex stainless steel pump casing. The investment casting process uses quartz powder as a coating, which cannot guarantee the strength and wear resistance of the shell, and the uniformity and density of the prepared shell are poor. Summary of the invention

[0008] The object of the present invention is to provide a casting process for a high-efficiency investment casting rotary kiln half gear ring casting to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps: S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing, wherein the smelting metal and pouring steps are as follows: (1) raw material preparation; (2) metal smelting; (3) adding deoxidizer; (4) using refining agent; (5) pouring after smelting.

[0010] Preferably, the mold design steps are as follows: according to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used to design and analyze the mold to ensure the accuracy and reliability of the mold, 3D printing technology is used to quickly manufacture the mold, the mold manufacturing cycle is shortened, and quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 1% to 3%, and the processing allowance is controlled at 5 to 10 mm.

[0011] Preferably, the wax pattern preparation steps are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax pattern, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand and cool and solidify for 2 minutes to 5 minutes, then demold the wax pattern to remove it, and prepare the wax pattern with the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0012] Preferably, the mold shell preparation steps are as follows: immersing the wax mold in a coating made by mixing silicon micropowder and clay, using a sand blasting machine to spray sand particles made by mixing quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold, the thickness of the thin shell is 0.5mm to 0.8mm, repeating the above process 3 to 5 times until a mold shell with a thickness of 2.5mm to 3mm is formed, and the mold shell has sufficient strength and rigidity to withstand subsequent smelting and pouring processes.

[0013] Preferably, the dewaxing step is as follows: heating the wax mold with the shell to 90° C. to 120° C. to discharge the wax from the shell to form a cavity.

[0014] Preferably, the step (1) raw material preparation: selecting high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; step (2) metal smelting: placing the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, closing the furnace door and sealing it, using a vacuum pump to draw out the gas inside the vacuum smelting furnace, and the vacuuming time is 30 seconds. The vacuum smelting furnace is turned on, and the temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and the refined carbon-nickel alloys, and the temperature is controlled at 1538°C to 2500°C. The smelting time is 10min to 20min to avoid excessive oxidation of the molten metal or the generation of other impurities; step (3) adding a deoxidizer: introducing an appropriate amount of aluminum powder during the vacuum smelting process to remove Remove oxygen and other harmful gases from the molten metal; Step (4) using a refining agent: adding chlorides during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; Step (5) pouring after smelting: after ensuring that the metal is completely melted, adjust the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1000°C to 1600°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm to 400mm / min.

[0015] Preferably, the cooling and cleaning steps are as follows: after the molten metal solidifies, the casting is taken out of the mold shell, and the flow rate and temperature of the cooling air are controlled to ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, a grinder is used to remove the casting gate and riser, and sand, coatings, oxides, and oil impurities on the surface of the casting are cleaned by mechanical cleaning and chemical cleaning.

[0016] Preferably, the defect inspection and post-processing steps are as follows: carefully inspect the surface and interior of the casting for cracks, pores, and shrinkage defects, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and precision, and then paint it to obtain a rotary kiln half gear ring casting.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention uses advanced smelting equipment and pure metal raw materials in the metal smelting process, selects pure metal iron blocks and refined carbon-nickel alloys as raw materials, can reduce the impurity content in the raw materials, uses a vacuum smelting furnace for hot melting, can improve the purity and quality of the molten metal, accurately controls the smelting temperature and time of the metal iron blocks and the refined carbon-nickel alloy to avoid excessive oxidation of the molten metal or the generation of other impurities, uses advanced smelting equipment to improve the purity and quality of the molten metal while reducing casting defects, reduces production costs and energy consumption, and improves the efficiency and quality of the rotary kiln half-gear ring investment casting process.

[0019] 2. The present invention adds deoxidizer and refining agent during metal smelting, introduces appropriate amount of aluminum powder during vacuum smelting to remove oxygen and other harmful gases in the molten metal, reduces the oxygen content in the molten metal, reduces shrinkage cavities, looseness and other defects in the molten metal, improves the density and mechanical properties of the casting after pouring, adds chloride during vacuum smelting to react chemically with impurities in the molten metal, and regularly skims off scum that is easy to remove to reduce the impact of impurities on the molten metal, adopts side pouring to meet the special requirements of the rotary kiln half gear ring, ensures that the molten metal can fill the cavity evenly and quickly, reduces pouring time and energy consumption, reduces the possibility of oxidation of the molten metal and mixing of impurities, and further improves the quality and efficiency of the rotary kiln half gear ring casting.

[0020] 3. The present invention uses polyethylene wax as a wax mold forming raw material and fills the mold with molten polyethylene wax. Polyethylene wax has good toughness and heat resistance and a small shrinkage rate, so a relatively stable wax mold can be produced. Polyethylene wax has good processing performance and is easy to demold, which can effectively ensure the quality and stability of the wax mold and reduce the defect rate of the wax mold. After the wax mold is filled, a blowtorch is used to accelerate the cooling and solidification process of the wax mold to ensure the accuracy and strength of the wax mold, thereby ensuring the stability of subsequent processing of investment casting.

[0021] 4. The present invention adopts a new type of coating and sand material to prepare the mold shell, immerses the wax mold in a coating made of a mixture of silicon micropowder and clay, and uses silicon micropowder with good quality and relatively stable particle size instead of ordinary quartz powder as a refractory material to improve the quality stability of the mold shell. Corundum sand has high hardness and wear resistance, and can effectively enhance the strength and wear resistance of the mold shell. Sand particles mixed with quartz sand and corundum sand are sprayed on the outside of the coating to form a thin shell on the surface of the wax mold. The mold shell has sufficient strength and rigidity to withstand subsequent smelting and pouring processes. The coating thickness and the number of spraying times during the preparation of the mold shell are optimized to improve the uniformity and density of the mold shell, thereby ensuring the production quality of rotary kiln half-gear ring castings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The investment casting process flow chart of the present invention;

[0023] Figure 2 It is a schematic diagram of the influence of different casting factors on casting properties of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments 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.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection or a movable connection, or a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Embodiment 1, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0028] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 2%, and the processing allowance is controlled at 5mm.

[0029] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 5 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0030] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 2.5mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0031] The dewaxing steps are as follows: heat the wax mold with the shell to 120°C to allow the wax to be discharged from the shell to form a cavity.

[0032] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 1538°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of Aluminum powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1000°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150 / min.

[0033] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0034] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0035] Embodiment 2, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0036] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 2% and the processing allowance is controlled at 5mm.

[0037] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 5 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0038] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 3mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0039] The dewaxing steps are as follows: heat the wax mold with the shell to 120°C to allow the wax to be discharged from the shell to form a cavity.

[0040] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 1538°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of aluminum is introduced. Powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1000°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm / min.

[0041] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0042] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0043] Depend on Figure 2 It can be seen that when the hot melt temperature, smelting time, pouring temperature and pouring speed are consistent, the rotary kiln half gear ring casting prepared in Example 1 with a shell thickness of 3 mm has better compressive strength.

[0044] Embodiment 3, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0045] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 1% and the processing allowance is controlled at 5mm.

[0046] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 2 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0047] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 2.5mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0048] The dewaxing steps are as follows: heat the wax mold with the shell to 9°C to allow the wax to be discharged from the shell to form a cavity.

[0049] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 1538°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of aluminum is introduced. Powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1000°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm / min.

[0050] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0051] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0052] Embodiment 4, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0053] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 1% and the processing allowance is controlled at 5mm.

[0054] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 2 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0055] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 2.5mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0056] The dewaxing steps are as follows: heat the wax mold with the shell to 90°C to allow the wax to be discharged from the shell to form a cavity.

[0057] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 1538°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of aluminum is introduced. Powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1600°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm / min.

[0058] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0059] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0060] Depend on Figure 2 It can be seen that when the shell thickness, hot melt temperature, smelting time and pouring speed are consistent, shrinkage defects will occur inside the rotary kiln half gear ring casting prepared in Example 3 with a pouring temperature of 1000°C as detected by an ultrasonic flaw detector.

[0061] Embodiment 5, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0062] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 3% and the processing allowance is controlled at 10mm.

[0063] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 5 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0064] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 3mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0065] The dewaxing steps are as follows: heat the wax mold with the shell to 120°C to allow the wax to be discharged from the shell to form a cavity.

[0066] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 2500°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of aluminum is introduced. Powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1600°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm / min.

[0067] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0068] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0069] Embodiment 6, an embodiment provided by the present invention: a casting process for a high-efficiency investment casting rotary kiln half gear ring casting, comprising the following steps; S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, smelting metal and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing.

[0070] The mold design steps are as follows: According to the design drawings of the rotary kiln half gear ring casting, advanced CAD technology is used for mold design and analysis to ensure the accuracy and reliability of the mold. 3D printing technology is used to quickly manufacture the mold and shorten the mold manufacturing cycle. Quality modular design is introduced to facilitate rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 3% and the processing allowance is controlled at 10mm.

[0071] The steps for preparing the wax model are as follows: fill the mold with molten polyethylene wax, use a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, let it stand to cool and solidify for 5 minutes, then demold the wax model to remove it. The prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting.

[0072] The steps for preparing the mold shell are as follows: immerse the wax mold in a coating made of a mixture of silicon micropowder and clay, use a sand blasting machine to spray sand particles made of a mixture of quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold. The thickness of the thin shell is 0.5mm to 0.8mm. Repeat the above process 3 to 5 times until a mold shell with a thickness of 3mm is formed. The mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes.

[0073] The dewaxing steps are as follows: heat the wax mold with the shell to 120°C to allow the wax to be discharged from the shell to form a cavity.

[0074] The steps of smelting metal and pouring are as follows: Step (1) Raw material preparation: Select high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; Step (2) Metal smelting: Put the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, close the furnace door and seal it, and use a vacuum pump to draw out the gas inside the vacuum smelting furnace. The vacuum time is 30 seconds, and the vacuum smelting furnace is turned on. The temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys. The temperature is controlled at 2500°C and the smelting time is 10 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; Step (3) Adding a deoxidizer: During the vacuum smelting process, an appropriate amount of aluminum is introduced. powder, remove oxygen and other harmful gases in the molten metal; step (4) using a refining agent: adding chloride during the vacuum smelting process to react chemically with impurities in the molten metal, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the molten metal; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1600°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 400mm / min.

[0075] The cooling and cleaning steps are as follows: After the molten metal solidifies, remove the casting from the mold shell. By controlling the flow and temperature of the cooling air, ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Use mechanical and chemical cleaning to clean the sand, paint, oxides, and oil impurities on the surface of the casting.

[0076] The defect inspection and post-processing steps are as follows: carefully check whether there are cracks, pores, and shrinkage defects on the surface and inside of the casting, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain the rotary kiln half gear ring casting.

[0077] Depend on Figure 2 It can be seen that when the shell thickness, hot melt temperature, smelting time and pouring temperature are consistent, the surface of the rotary kiln half gear ring casting obtained in Example 6 with a pouring speed of 400 mm / min detected by the surface roughness detector is rougher.

[0078] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A casting process for high-efficiency investment casting of rotary kiln half gear ring castings, characterized by: The method comprises the following steps: S1, mold design; S2, wax mold preparation; S3, shell preparation; S4, dewaxing; S5, metal smelting and pouring; S6, cooling and cleaning; S7, defect inspection and post-processing, wherein the metal smelting and pouring steps are as follows: (1) raw material preparation; (2) metal smelting; (3) adding deoxidizer; (4) using refining agent; (5) pouring after smelting; The mold design steps are as follows: according to the design drawings of the rotary kiln half gear ring casting, the advanced CAD technology is used to design and analyze the mold to ensure the accuracy and reliability of the mold, the 3D printing technology is used to quickly manufacture the mold, the mold manufacturing cycle is shortened, and the quality modular design is introduced to facilitate the rapid replacement and maintenance of the mold. The mold shrinkage rate is controlled at 1% to 3%, and the processing allowance is controlled at 5 to 10 mm; The wax model preparation steps are as follows: filling the mold with molten polyethylene wax, using a blowtorch to accelerate the cooling and solidification process of the wax model, and when the surface of the polyethylene wax begins to harden and becomes no longer sticky, standing to cool and solidify for 2 minutes to 5 minutes, and then demolding the wax model to remove it, and the prepared wax model has the same shape and size as the finished product of the rotary kiln half gear ring casting; The mold shell preparation steps are as follows: immersing the wax mold in a coating made by mixing silicon micropowder and clay, using a sand blasting machine to spray sand particles made by mixing quartz sand and corundum sand on the outside of the coating to form a thin shell on the surface of the wax mold, the thickness of the thin shell is 0.5mm-0.8mm, repeating the above process 3-5 times until a mold shell with a thickness of 2.5mm-3mm is formed, and the mold shell has sufficient strength and rigidity to withstand subsequent melting and pouring processes; The dewaxing step is as follows: heating the wax mold with the shell to 90°C to 120°C to discharge the wax from the shell to form a cavity; The step (1) raw material preparation: selecting high-quality raw materials, pure metal iron blocks and refined carbon-nickel alloys; step (2) metal smelting: placing the metal iron blocks and refined carbon-nickel alloys into a vacuum smelting furnace, closing the furnace door and sealing it, using a vacuum pump to draw out the gas inside the vacuum smelting furnace, and evacuating the furnace for 30 seconds. The vacuum smelting furnace is turned on, and the temperature in the furnace is raised to the hot melting temperature of the metal iron blocks and refined carbon-nickel alloys, and the temperature is controlled at 1538°C to 2500°C. The smelting time is 10 minutes to 20 minutes to avoid excessive oxidation of the molten metal or the generation of other impurities; step (3) adding a deoxidizer: introducing an appropriate amount of aluminum powder during the vacuum smelting process to remove the metal. Oxygen and other harmful gases in the metal liquid; step (4) using a refining agent: adding chlorides during the vacuum smelting process to react chemically with impurities in the metal liquid, and regularly skimming off scum that is easy to remove to reduce the impact of impurities on the metal liquid; step (5) pouring after smelting: after ensuring that the metal is completely melted, adjusting the heat source power of the vacuum smelting furnace to adjust the pouring temperature, the pouring temperature is maintained at 1000°C to 1600°C, the mold shell is preheated, and the molten metal liquid is poured into the dewaxed mold shell to fill the cavity, and side pouring is used to meet the special requirements of the rotary kiln half gear ring, improve the quality and efficiency of the casting, and the pouring speed is controlled at 150mm to 400mm / min.

2. The casting process of a high-efficiency investment casting rotary kiln half gear ring casting according to claim 1, characterized in that: The cooling and cleaning steps are as follows: after the molten metal solidifies, the casting is taken out of the mold shell, and the flow rate and temperature of the cooling air are controlled to ensure that the casting is heated evenly during the entire cooling process to avoid excessive local temperature differences. After natural cooling, a grinder is used to remove the casting gate and riser, and sand, coatings, oxides, and oil impurities on the surface of the casting are cleaned by mechanical cleaning and chemical cleaning.

3. The casting process of a high-efficiency investment casting rotary kiln half gear ring casting according to claim 2 is characterized in that: The defect inspection and post-processing steps are as follows: carefully inspect the surface and interior of the casting for cracks, pores, and shrinkage defects, perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties, perform mechanical processing to make the casting reach the required size and accuracy, and then paint it to obtain a rotary kiln half gear ring casting.

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