Method for solving problems of columnar crystals and insufficient casting by using wax mold wrapped profiling heat preservation sheet

Abstract

The invention discloses a method for wrapping a profiling heat preservation sheet with a wax mold to solve the problem of columnar crystals and insufficient casting, and belongs to the technical field of precision casting. According to the method, a mounting groove for mounting the profiling heat preservation sheet is reserved in a cavity of a wax mold during production of the wax mold, and the profiling heat preservation sheet is placed in the mounting groove to be integrally formed with a part wax mold; then the part wax mold is subjected to slurry coating and sand hanging, the profiling heat preservation sheet is embedded in the inner cavity of the mold shell, the position of the profiling heat preservation sheet on the part wax mold is accurately controlled through the mounting groove, then the profiling heat preservation sheet is embedded in the inner cavity of the part mold shell, the profiling heat preservation sheet is not moved in the whole process, and the final mounting position of the profiling heat preservation sheet is accurate; in the final smelting and pouring process, the temperature of the molten metal, needing to be additionally provided with the profiling heat preservation sheet, of the part can be accurately controlled, so that the solidification sequence of the molten metal is accurately controlled, the final solidification sequence of the molten metal meets the expectation, a casting based on accurate temperature control is obtained, the quality of the final part is improved, and the rejection rate of products is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of precision casting, and specifically to a method for using a wax pattern wrapped with a profiling heat preservation sheet to solve the problems of columnar crystals and undercasting. Background Art

[0002] When producing aeroengine parts by investment precision casting, it is easy to generate coarse columnar crystals in the thin-wall area, reducing the mechanical properties and service life of the parts. To meet the working performance requirements of aeroengines, columnar crystals are not allowed in the parts. To solve the problem of columnar crystals, the process parameters of melting and pouring are adjusted. For example, reducing the pouring temperature will cause undercasting on the exhaust side. These two are contradictory to each other, and it is difficult to balance the process parameters to ensure both complete filling and qualified crystal grains.

[0003] The current solution is to add a heat preservation subsidy in the thin-wall area of the part to reduce the temperature gradient between the thin-wall area and the thick and large area during the melting and pouring process, eliminate the growth environment of columnar crystals, and thus avoid columnar crystals.

[0004] For example, the Chinese invention patent with the authorization announcement number CN104325081B discloses a preparation method of a composite mold shell with an internal implanted heat preservation material. By putting the heat preservation material into the mold shell when applying slurry and hanging sand, the temperature field and the change of temperature gradient during the solidification process of the casting after pouring are improved, and the purpose of obtaining uniform equiaxed crystal grains is achieved.

[0005] However, whether directly wrapping a heat preservation subsidy outside the mold shell or putting the heat preservation material into the mold shell as in the above-mentioned invention patent, the heat preservation material is attached to the mold shell, and manual operation is used when attaching the heat preservation subsidy. The boundary position of the heat preservation subsidy cannot be accurately controlled. For some positions with gradually changing wall thickness, such as the exhaust side of the blade, the wall thickness of the heat preservation material is also in a gradually changing state. At this time, inaccurate attachment position of the heat preservation subsidy will cause the thickness of the heat preservation subsidy on the mold shell surface to be inconsistent with the preset thickness, resulting in the final temperature field of the molten metal not reaching the expected effect, thus affecting the product quality. The product quality is greatly affected by manual operation, and the scrap rate of the final product is relatively high.

[0006] Based on this, the present invention designs a method for using a wax pattern wrapped with a profiling heat preservation sheet to solve the problems of columnar crystals and undercasting to solve the above problems. Summary of the Invention

[0007] To achieve the above object, the present invention provides the following technical solution: A method for using a wax pattern wrapped with a profiling heat preservation sheet to solve the problems of columnar crystals and undercasting, including the following steps:

[0008] S1, fabricating a profiling heat preservation sheet: Determine the shape and size of the profiling heat preservation sheet according to the part structure, and fabricate the profiling heat preservation sheet.

[0009] S2. Make the wax mold: Make the wax mold according to the part after wrapping the profile heat preservation sheet, so that the cavity of the wax mold contains the installation groove for installing the profile heat preservation sheet;

[0010] S3. Press the blade wax mold: Place the profile heat preservation sheet in the installation groove of the wax mold, and press the part wax mold through the wax mold to obtain the part wax mold wrapped with the profile heat preservation sheet;

[0011] S4. Make the part mold shell: After applying slurry, hanging sand, and dewaxing on the surface of the part wax mold, obtain the part mold shell embedded with the profile heat preservation sheet;

[0012] S5. Melting and pouring: Use the part mold shell embedded with the profile heat preservation sheet to carry out the melting and pouring process to pour the part and form a casting;

[0013] S6. Clean the part surface: Remove the part mold shell and the profile heat preservation sheet on the surface of the casting.

[0014] As a further scheme of the present invention, in step S1, determine the thickness of different positions of the profile heat preservation sheet according to the heat conduction coefficient of the profile heat preservation sheet and the heat preservation conditions required for the installation position of the profile heat preservation sheet on the part surface.

[0015] As a further scheme of the present invention, in step S6, use the part mold shell removal method to remove the part mold shell and the profile heat preservation sheet on the surface of the casting. When the profile heat preservation sheet cannot be removed by the part mold shell removal method, use the ceramic core decoring method to remove the profile heat preservation sheet.

[0016] As a further scheme of the present invention, the cross section of the profile heat preservation sheet is U-shaped, and an air chamber is arranged on one side of the inner cavity of the profile heat preservation sheet far away from the opening. The air chamber is used to discharge the gas in the part mold shell during the melting and pouring process.

[0017] As a further scheme of the present invention, the opening width of the air chamber is 0.1 - 0.3 mm.

[0018] As a further scheme of the present invention, the projection of the air chamber in its length direction is funnel-shaped, and the width of the air chamber at one end far away from the inner cavity of the profile heat preservation sheet is greater than its opening width.

[0019] As a further scheme of the present invention, the profile heat preservation sheet is made of a material with a surface friction resistance smaller than the surface friction coefficient of the part mold shell.

[0020] As a further scheme of the present invention, the profile heat preservation sheet is made of a material with the same thermal expansion coefficient as that of the part mold shell.

[0021] As a further scheme of the present invention, the profile heat preservation sheet is made of a rigid material.

[0022] As a further solution of the present invention, the profiling heat preservation sheet is made of a material with a thermal conductivity lower than that of the part mold shell.

[0023] The present invention has the following beneficial effects:

[0024] 1. By wrapping the profiling heat preservation sheet on the surface of the casting wax mold, and insulating the molten metal in a specific area through the profiling heat preservation sheet, the solidification sequence of the final molten metal conforms to the expectation, obtaining a casting based on precise temperature control, eliminating the growth environment of columnar crystals, and improving the heat preservation effect of the area wrapped by the profiling heat preservation sheet, so that the molten metal dissipates heat more slowly, has better fluidity, and improves the problem of undercasting.

[0025] 2. When producing the wax mold mold, an installation groove for installing the profiling heat preservation sheet is reserved in the cavity of the wax mold mold. The profiling heat preservation sheet is placed in the installation groove and integrally formed with the part wax mold. Subsequently, the part wax mold wrapped with the profiling heat preservation sheet is coated with slurry and sanded, so that the profiling heat preservation sheet is embedded in the inner cavity of the mold shell. The position of the profiling heat preservation sheet on the part wax mold is precisely controlled through the installation groove. Subsequently, the profiling heat preservation sheet is embedded in the inner cavity of the part mold shell. The profiling heat preservation sheet does not move during the whole process, so that the installation position of the final profiling heat preservation sheet is precise. When finally melting and pouring, the temperature of the molten metal at the position where the profiling heat preservation sheet needs to be added to the part can be precisely controlled to precisely control the solidification sequence of the molten metal, so that the solidification sequence of the final molten metal conforms to the expectation, obtaining a casting based on precise temperature control to improve the quality of the final part and reduce the scrap rate of the product. At the same time, when using this method to install the profiling heat preservation sheet, the profiling heat preservation sheet can be mass-produced, the installation of the profiling heat preservation sheet is more standardized, not affected by the manual error of the staff, and the temperature field distribution of the molten metal can be more precisely controlled, thereby improving the quality of the finally obtained casting.

[0026] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The following will refer to the drawings to further elaborate on the present invention in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0028] Figure 1 is a flow chart of this method.

[0029] Figure 2 is a schematic structural diagram of the profiling heat preservation sheet in this method.

[0030] Figure 3 is a schematic diagram of the leaf wax mold pressing step in this method.

[0031] Figure 4 Schematic diagram of the part wax mold wrapped with a profiling heat preservation sheet

[0032] Figure 5 Schematic diagram of the wax mold of the turbine component

[0033] Legend description:

[0034] 1. Profiling heat preservation sheet; 11. Air chamber Specific implementation mode

[0035] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following.

[0036] Please refer to Figures 1-5 , the present invention provides a technical solution: a method for a wax mold wrapped with a profiling heat preservation sheet to solve the problems of columnar crystals and undercasting, including the following steps:

[0037] S1. Fabricate the profiling heat preservation sheet 1: Determine the shape and size of the profiling heat preservation sheet 1 according to the part structure, and fabricate the profiling heat preservation sheet 1;

[0038] Determining the shape and size of the profiling heat preservation sheet 1 according to the part structure is a prior art and will not be elaborated here. Design the shape and size of the profiling heat preservation sheet 1 according to the part structure so that the profiling heat preservation sheet 1 can just cover the area on the part surface where the profiling heat preservation sheet 1 needs to be added. Subsequently, produce the profiling heat preservation sheet 1 according to the obtained shape and size of the profiling heat preservation sheet 1;

[0039] Generally, the position on the part surface where the profiling heat preservation sheet 1 needs to be added is the thin-wall area of the part to control the solidification sequence of the molten metal during pouring;

[0040] S2. Fabricate the wax mold die: Fabricate the wax mold die according to the part after wrapping the profiling heat preservation sheet 1, so that the cavity of the wax mold die contains an installation groove for installing the profiling heat preservation sheet 1;

[0041] When designing the wax mold die, in order to integrally press-mold the profiling heat preservation sheet 1 and the part wax mold, it is necessary to reserve the position of the profiling heat preservation sheet 1 in the cavity of the wax mold die. Therefore, use the part wrapped with the profiling blade as the design basis for the cavity of the wax mold die, so that the finally designed cavity of the wax mold die contains an installation groove for presetting the profiling heat preservation sheet 1. After the wax mold die design is completed, produce according to the designed wax mold die to obtain a wax mold die with an internal installation groove;

[0042] S3. Press the blade wax mold: Place the profiling heat preservation sheet 1 in the installation groove of the wax mold die, and press the part wax mold through the wax mold die to obtain a part wax mold wrapped with the profiling heat preservation sheet 1;

[0043] Before pressing the part wax pattern through the wax pattern mold, first place the profiling heat-insulating sheet 1 at the position of the installation groove in the wax pattern mold, fix the position of the profiling heat-insulating sheet 1 through the installation groove, and then normally carry out the pressing process of the part wax pattern. During the pressing process, the wax pattern will slowly fill the cavity inside the wax pattern mold and directly contact the profiling heat-insulating sheet 1 placed in the installation groove. After waiting for the part wax pattern to solidify and form, open the wax pattern mold and take out the part wax pattern from the wax pattern mold. At this time, the profiling heat-insulating sheet 1 is wrapped on the surface of the part wax pattern. By reserving the position of the profiling heat-insulating sheet 1 in the wax pattern mold at the design stage, it is ensured that the profiling heat-insulating sheet 1 can accurately wrap the position on the part surface where the profiling heat-insulating sheet 1 needs to be added;

[0044] S4. Manufacture the part shell mold: After coating the part wax pattern with slurry, hanging sand, and dewaxing, obtain the part shell mold with the profiling heat-insulating sheet 1 embedded;

[0045] After obtaining the part wax pattern wrapped with the profiling heat-insulating sheet 1, the manufacture of the part shell mold can be carried out. When manufacturing the part shell mold, use the same method as the traditional process. Normally, coat the part wax pattern with slurry and then hang sand. After hanging sand to the designed thickness, heat the part shell mold to melt the part wax pattern inside the part shell mold. At this time, the profiling heat-insulating sheet 1 is wrapped into the part shell mold, and the part shell mold with the profiling heat-insulating sheet 1 in the inner cavity is obtained. Since the profiling heat-insulating sheet 1 is positioned on the part wax pattern through the installation groove and then transferred to the inner cavity of the part shell mold through the part wax pattern, during this process, the profiling heat-insulating sheet 1 always remains in a fixed state, which can ensure the accurate position of the final profiling heat-insulating sheet 1 in the part shell mold;

[0046] S5. Melting and pouring: Use the part shell mold with the profiling heat-insulating sheet 1 embedded to carry out the melting and pouring process to pour the part and form a casting;

[0047] After obtaining the part shell mold with the profiling heat-insulating sheet 1 in the inner cavity, carry out the melting and pouring procedure, transport the melted metal material to the inner cavity of the part shell mold. During the cooling process of the molten metal, the profiling heat-insulating sheet 1 can make the thin-walled area of the part have better heat-insulating conditions, reduce the temperature gradient between the thin-walled area of the part and other thick and large parts, eliminate the growth environment of columnar crystals, thereby avoiding the generation of columnar crystals. Since the installation position of the profiling heat-insulating sheet 1 in the part shell mold is accurate, the profiling heat-insulating sheet 1 can accurately control the temperature of the thin-walled area of the part, accurately control the solidification sequence of the molten metal during melting and pouring, improve the temperature control effect, and further improve the product quality and the yield rate of the product;

[0048] S6. Clean the part surface: Remove the part shell mold and the profiling heat-insulating sheet 1 on the surface of the casting;

[0049] After obtaining the casting through melting and pouring, it is necessary to clean the part shell mold and the profiling heat-insulating sheet 1 on the surface of the casting to obtain a clean casting.

[0050] After obtaining the area where the profiling heat preservation sheet 1 needs to be added to the part, the profiling heat preservation sheet 1 is designed and produced to ensure that the produced profiling heat preservation sheet 1 can accurately cover the area where the profiling heat preservation sheet 1 needs to be added to the part surface. At the same time, when producing the wax mold of the part, the part wrapped with the profiling heat preservation sheet 1 is used as the design basis for the inner cavity of the wax mold. In this way, the inner cavity of the produced wax mold contains the installation groove for placing the profiling heat preservation sheet 1. When pressing the part wax mold through the wax mold, the profiling heat preservation sheet 1 can be placed in the installation groove opened in the inner cavity of the wax mold first, and then the part wax mold is pressed, so that the surface of the finally pressed part wax mold is wrapped with the profiling heat preservation sheet 1. And because the inner cavity of the wax mold is designed according to the part wrapped with the profiling heat preservation sheet 1, the wrapping position of the profiling heat preservation sheet 1 on the finally obtained part wax mold is very accurate. Subsequently, the part wax mold wrapped with the profiling heat preservation sheet 1 is used to make the part mold shell. When making the part mold shell, the traditional part mold shell making process is adopted. The profiling heat preservation sheet 1 wrapped on the part wax mold before is embedded in the inner cavity wall of the part mold shell at this time. And because the profiling heat preservation sheet 1 is transferred from the part wax mold to the part mold shell through the part mold shell making process, it can ensure that the profiling heat preservation sheet 1 is accurately transferred to the inner cavity wall of the part mold shell. When finally carrying out melting and pouring, the temperature of the molten metal at the position where the profiling heat preservation sheet 1 needs to be added to the part can be accurately controlled to accurately control the solidification sequence of the molten metal, so that the solidification sequence of the final molten metal meets the expectation, and a casting based on accurate temperature control is obtained to improve the quality of the final part and reduce the scrap rate of the product.

[0051] At the same time, by using this method to install the profiling heat preservation sheet 1, the profiling heat preservation sheet 1 can be mass-produced, and the installation of the profiling heat preservation sheet 1 is more standardized, not affected by the manual error of the staff, and the temperature field distribution of the molten metal can be controlled more accurately, thereby improving the quality of the finally obtained casting.

[0052] Further, in step S1, the thickness of different positions of the profiling heat preservation sheet 1 is determined according to the heat conduction coefficient of the profiling heat preservation sheet 1 and the heat preservation conditions required for the installation position of the profiling heat preservation sheet 1 on the part surface;

[0053] As Figure 2 shown, when installing the profiling heat preservation sheet 1 on the exhaust edge of the blade in the turbine component, since the blade wall thickness gradually decreases towards the exhaust edge, therefore, when designing the profiling heat preservation sheet 1, the wall thickness of the profiling heat preservation sheet 1 gradually increases in the same direction, and the thickness of the profiling heat preservation sheet 1 in the area with a small wall thickness is larger, so as to obtain a better heat preservation effect and further reduce the temperature gradient caused by the wall thickness difference.

[0054] In step S6, the part mold shell and the profiling heat preservation sheet 1 on the surface of the casting are removed by the part mold shell removal method. When the profiling heat preservation sheet 1 cannot be removed by the part mold shell removal method, the profiling heat preservation sheet 1 is removed by the ceramic core core removal method. After the molten metal is cooled to obtain the casting of the part, the part mold shell on the surface of the casting needs to be cleaned. When cleaning the part mold shell, first, the part mold shell on the surface of the casting is removed by the traditional part mold shell removal method. When the profiling heat preservation sheet 1 cannot be removed by the part mold shell removal method, the profiling heat preservation sheet 1 can be removed by the ceramic core core removal method.

[0055] Figures 2-5 An embodiment is disclosed. In this embodiment, the part is a certain type of alloy turbine component. Due to the structural differences of the turbine component and the thickness differences between the exhaust side and the intake side of the blade, columnar crystals perpendicular to the stress direction often appear on the exhaust side of the blade, resulting in the scrapping of the casting. Therefore, it is necessary to add a heat preservation subsidy at the exhaust side position of the turbine component to reduce the heat dissipation rate of the molten metal at the exhaust side position of the turbine component, so as to reduce the temperature gradient between the exhaust side and the thick and large parts of the turbine component, eliminate the growth environment of columnar crystals, and thus avoid columnar crystals. Therefore, the profiling heat preservation sheet 1 is Figure 2 designed to be strip-shaped with a U-shaped cross-section as shown, and is used to wrap the exhaust side of the turbine component. In this embodiment, since the structure of the turbine component is relatively complex, the turbine component needs to be split into multiple modules for wax mold forming, and then the module wax molds are spliced to form the overall wax mold of the turbine component. The profiling heat preservation sheet 1 is arranged at the exhaust side of the blade in the turbine component. At the same time, when splitting the wax mold of the turbine component, the blade in the turbine component is split into individual unit blade modules. Therefore, when designing the wax mold die of the unit blade, it is necessary to design the wax mold die of the unit blade based on the blade unit wrapping the profiling heat preservation sheet 1, as Figure 3 shown. The internal cavity of the final unit blade wax mold die includes the cavity for forming the unit blade and the installation groove for accommodating the profiling heat preservation sheet 1. When forming the unit blade through the unit blade wax mold die, first place the profiling heat preservation sheet 1 in the installation groove opened in the internal cavity of the wax mold die, and then press the unit blade wax mold, as Figure 4 shown, so that the exhaust side position of the finally formed unit blade wax mold is wrapped by the profiling heat preservation sheet 1. Then, the unit blade wax mold is spliced with the remaining module wax molds to obtain Figure 5The wax pattern of the turbine component shown. At this time, the exhaust side of the wax pattern of the turbine component is entirely wrapped with the profiling heat-insulating sheet 1, and the position of the profiling heat-insulating sheet 1 is accurate. Subsequently, the wax pattern of the turbine component is slurried and sand-hung using traditional techniques. After dewaxing, a part mold shell of the turbine component with the profiling heat-insulating sheet 1 embedded therein is obtained. At this time, the profiling heat-insulating sheet 1 is provided at the position of the exhaust side in the inner cavity of the part mold shell of the turbine component, which can enhance the heat-insulating effect at the position of the exhaust side during the subsequent melting and pouring process, so as to reduce the temperature gradient between the molten metal at the exhaust side position and the molten metal in the remaining thick and large areas, eliminate the growth environment of columnar crystals, thereby avoiding columnar crystals. At the same time, the installation position of the profiling heat-insulating patch is precise, which can effectively improve the quality of the final casting and reduce the rejection rate of the casting.

[0056] Preferably, an air chamber 11 is provided on the side of the inner cavity of the profiling heat-insulating sheet 1 far away from the opening. The air chamber 11 is used to discharge the gas in the part mold shell during the melting and pouring process, prevent air from being trapped during the filling process of the molten metal, and prevent undercasting at the exhaust side position of the turbine component;

[0057] Since the profiling heat-insulating sheet 1 is generally arranged in the thin-wall area of the part, as Figures 2-3 shown, when the profiling heat-insulating sheet 1 is used for installation at the exhaust side position of the turbine component, the wall thickness at the exhaust side position of the blade is thin, so it is easy to have air trapped and cause undercasting. Therefore, an air chamber 11 can be provided on the side of the inner cavity of the profiling heat-insulating sheet 1 far away from the opening. The air chamber 11 can be used to accommodate air. During the pouring process, if there is residual gas in the part mold shell, the gas can be squeezed into the air chamber 11 by the molten metal, preventing the gas from being trapped in the part mold shell and causing air entrapment. The air chamber 11 is provided in the inner cavity of the profiling heat-insulating sheet 1 and does not belong to the part. Thus, discharging the gas into the air chamber 11 is equivalent to discharging the gas from the part mold shell, so that the gas no longer affects the complete forming of the exhaust side and solves the problem of undercasting at the exhaust side.

[0058] Furthermore, the opening width of the air chamber 11 is 0.1 - 0.3 mm, which is used to prevent the molten metal from entering the air chamber 11 and prevent overfilling of the molten metal;

[0059] When the gas in the part mold shell is squeezed into the air chamber 11 by the molten metal, the molten metal may also enter the air chamber 11, which may cause overfilling of the molten metal. In order to prevent the molten metal from entering the air chamber 11, the opening width of the air chamber 11 is 0.1 - 0.3 mm, so that while the gas can enter the air chamber 11 normally, the molten metal cannot enter the air chamber;

[0060] Furthermore, the projection of the air chamber 11 in its length direction is funnel-shaped, and the width of the end of the air chamber 11 far away from the inner cavity of the profiling heat-insulating sheet 1 is greater than its opening width, so that the space for accommodating gas in the air chamber 11 is increased, and the air chamber 11 can accommodate more gas.

[0061] The profiled heat-insulating sheet 1 is made of a material whose surface friction resistance is smaller than the surface friction coefficient of the part mold shell, which can reduce the friction resistance of the molten metal when flowing in the profiled heat-insulating sheet 1, and is conducive to the filling of the molten metal;

[0062] When the contoured thermal insulation sheet 1 is arranged on the exhaust edge of the blade in the turbine component, the friction resistance encountered by the molten metal during filling is large due to the small wall thickness of the exhaust edge, which is not conducive to the filling of the molten metal. After the contoured thermal insulation sheet 1 is pre-placed in the part mold shell by the present method, the contoured thermal insulation sheet 1 is directly in contact with the molten metal. By controlling the material of the contoured thermal insulation sheet 1, the surface friction coefficient of the contoured thermal insulation sheet 1 is made smaller than the surface friction coefficient of the part mold shell. Therefore, when the molten metal is filled to the exhaust edge area of ​​the blade, it will contact the contoured thermal insulation sheet 1. Compared with the traditional part mold shell, the molten metal encounters less friction resistance when contacting the contoured thermal insulation sheet 1, which is more conducive to the filling of the molten metal, thereby further reducing the probability of undercasting.

[0063] The profiled insulation sheet 1 is made of a material with the same thermal expansion coefficient as that of the part mold shell, so as to ensure that the size changes of the part mold shell and the profiled insulation sheet 1 are consistent during the heating process, and to avoid the profiled insulation sheet 1 from bursting the external part mold shell or shaking due to poor positioning;

[0064] During the melting and pouring process, the part mold shell and the contoured insulation sheet 1 need to be heated. Only when the thermal expansion coefficient of the contoured insulation sheet 1 is consistent with the thermal insulation coefficient of the part mold shell can the contoured insulation sheet 1 and the part mold shell always maintain a close fit during the heating process to prevent the contoured insulation sheet 1 from changing greatly in size and cracking the external part mold shell. At the same time, it also prevents the mold shell from changing greatly in size and causing a gap between it and the contoured insulation sheet 1. When there is no material with the same thermal expansion coefficient as the part mold shell, the material with the thermal expansion coefficient closest to the part mold shell is used, provided that other performance requirements are met.

[0065] Preferably, the contoured insulation sheet 1 is made of rigid material to ensure that the contoured insulation sheet 1 can be firmly placed in the installation groove opened in the wax mold. At the same time, during the process of pressing the part wax mold and making the part mold shell, the contoured insulation sheet 1 will not be deformed to ensure the precise size of the final casting.

[0066] Preferably, the contoured insulation sheet 1 is made of a material having a lower thermal conductivity than the part mold shell, so that the contoured insulation sheet 1 has a better thermal insulation effect than the part mold shell, ensuring that the area wrapped around the contoured insulation sheet 1 has a better thermal insulation effect during the pouring process, thereby reducing the temperature gradient caused by the wall thickness during the cooling of the molten metal.

[0067] Preferably, the profiling heat-insulating sheet 1 is made of the same high-temperature ceramic material as the ceramic core, and the manufacturing process is the same as that of the current ceramic core. Since the ceramic core has been widely used in the field of melting and casting, the material properties have been verified through practice, and the production process is relatively perfect. At the same time, the method for removing the profiling heat-insulating sheet 1 at the end is also more perfect, which can accurately remove the profiling heat-insulating sheet 1 on the surface of the casting, and can reduce the material R & D cost.

[0068] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for solving the problems of columnar crystals and undercasting by wrapping a wax mold with a contoured thermal insulation sheet, characterized in that: The following steps are involved: S1, manufacturing a contoured thermal insulation sheet (1): determining the shape and size of the contoured thermal insulation sheet (1) according to the structure of the parts, and manufacturing the contoured thermal insulation sheet (1); S2, making a wax mold: making a wax mold according to the part after wrapping the contoured thermal insulation sheet (1), so that the cavity of the wax mold contains a mounting groove for mounting the contoured thermal insulation sheet (1); S3, blade wax mold pressing: placing a contoured thermal insulation sheet (1) in the mounting groove of the wax mold, and pressing the part wax mold through the wax mold to obtain a part wax mold wrapping the contoured thermal insulation sheet (1); S4, making a part mold shell: coating the surface of the part wax mold with slurry, sanding, and dewaxing to obtain a part mold shell with an embedded contour insulation sheet (1); S5, melting and pouring: using a part mold shell with an embedded contoured heat-insulating sheet (1) to perform a melting and pouring process to pour the part to form a casting; S6, cleaning the surface of the parts: removing the mold shell and the contoured insulation sheet (1) on the surface of the casting.

2. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: In step S1, the thickness of the contoured thermal insulation sheet (1) at different positions is determined according to the thermal conductivity coefficient of the contoured thermal insulation sheet (1) and the thermal insulation conditions required for the position where the contoured thermal insulation sheet (1) is installed on the surface of the component.

3. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: In step S6, a part mold shell removal method is used to remove the part mold shell and the contoured thermal insulation sheet (1) on the surface of the casting. When the contoured thermal insulation sheet (1) cannot be removed by the part mold shell removal method, a ceramic core de-coring method is used to remove the contoured thermal insulation sheet (1).

4. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: The cross section of the contoured thermal insulation sheet (1) is U-shaped, and an air chamber (11) is provided on a side of the inner cavity of the contoured thermal insulation sheet (1) away from the opening, and the air chamber (11) is used to discharge gas in the part mold shell during the smelting and pouring process.

5. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 4, characterized in that: The opening width of the air chamber (11) is 0.1-0.3 mm.

6. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 5, characterized in that: The projection of the air chamber (11) in the length direction thereof is funnel-shaped, and the width of the air chamber (11) at one end away from the inner cavity of the contoured heat-insulating sheet (1) is greater than the width of its opening.

7. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: The contoured heat-insulating sheet (1) is made of a material whose surface friction resistance is smaller than the surface friction coefficient of the part mold shell.

8. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: The contoured thermal insulation sheet (1) is made of a material having the same thermal expansion coefficient as that of the part mold shell.

9. The method of using a wax mold wrapped profiling insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: The contoured thermal insulation sheet (1) is made of rigid material.

10. The method of using a wax mold wrapped profiling thermal insulation sheet to solve the problems of columnar crystals and undercasting according to claim 1, characterized in that: The contoured thermal insulation sheet (1) is made of a material having a thermal conductivity coefficient lower than that of the part mold shell.

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