A method of using a wax pattern wrapping profiled heat shield to solve columnar grain and undercure problems

Abstract

The application discloses a wax mold wrapping profiled heat preservation sheet for solving columnar crystal and under-casting problems in the technical field of precision casting, and relates to a method for solving columnar crystal and under-casting problems, wherein during production of a wax mold, an installation groove for the profiled heat preservation sheet is reserved in a cavity of the wax mold, the profiled heat preservation sheet is placed in the installation groove and integrally formed with a part wax mold, then the part wax mold is coated with slurry and sand is hung, so that the profiled heat preservation sheet is embedded in an inner cavity of a mold shell, the position of the profiled heat preservation sheet on the part wax mold is accurately controlled through the installation groove, then the profiled heat preservation sheet is embedded in the inner cavity of the part mold shell, the profiled heat preservation sheet is not moved during the whole process, the installation position of the final profiled heat preservation sheet is accurate, when final melting and pouring are performed, the metal liquid at the position where the profiled heat preservation sheet needs to be additionally arranged can be accurately controlled in temperature, the solidification sequence of the metal liquid is accurately controlled, the solidification sequence of the final metal liquid meets the expectation, a casting based on accurate temperature control is obtained, and the quality of the final part is improved and the product scrap rate is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision casting, in particular to a method for solving the problems of columnar crystals and underfilling by wrapping a wax mold with a profiled heat preservation sheet. BACKGROUND

[0002] When producing an aero-engine part by using the investment casting method, coarse columnar crystals are easily generated in the thin-walled area, which reduces the mechanical properties and service life of the part. In order to meet the demand of the working performance of the aero-engine, the part is required to be free of columnar crystals. In order to solve the problem of columnar crystals, the smelting and pouring process parameters are adjusted, such as reducing the pouring temperature, which will also lead to underfilling at the exhaust edge. The two are contradictory and it is difficult to balance the process parameters to ensure complete filling and qualified grains.

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

[0004] For example, a Chinese invention patent with the authorization announcement number CN104325081B discloses a preparation method of a composite mold shell with internal implanted heat preservation material. The heat preservation material is placed in the mold shell when the slurry is coated and the sand is hung, which improves the temperature field and the change of the temperature gradient during the metal solidification process after the casting is poured, and thus the purpose of obtaining uniform equiaxed grain is achieved.

[0005] However, whether the heat preservation patch is directly wrapped outside the mold shell or the heat preservation material is placed in the mold shell as in the above-mentioned invention patent, the heat preservation material is attached to the mold shell. The attachment of the heat preservation patch is manually operated by artificial, which cannot accurately control the boundary position of the heat preservation patch. For some wall thickness gradually changing positions such as the exhaust edge of the blade, the wall thickness of the heat preservation material is also gradually changing. At this time, if the attachment position of the heat preservation patch is not accurate enough, the thickness of the heat preservation patch on the surface of the mold shell will not be consistent with the preset thickness, which will lead to the fact that the temperature field of the final metal liquid cannot reach the expected effect, thereby affecting the product quality. The product quality is greatly affected by artificial, and the scrap rate of the final product is high.

[0006] Based on this, the present application designs a method for solving the problems of columnar crystals and underfilling by wrapping a wax mold with a profiled heat preservation sheet to solve the above-mentioned problems. SUMMARY

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a method for solving the problems of columnar crystals and underfilling by wrapping a wax mold with a profiled heat preservation sheet, comprising the following steps:

[0008] S1, making a profiled heat preservation sheet: determining the shape and size of the profiled heat preservation sheet according to the structure of the part, and making the profiled heat preservation sheet;

[0009] S2, making a wax mold mold: according to the part wrapped with the profiled heat preservation sheet, the wax mold mold is made, so that the wax mold mold cavity contains the mounting groove for mounting the profiled heat preservation sheet;

[0010] S3, blade wax mold pressing: the profiled heat preservation sheet is placed in the mounting groove of the wax mold mold, and the part wax mold is pressed through the wax mold mold, so that the part wax mold wrapped with the profiled heat preservation sheet is obtained;

[0011] S4, making a part mold shell: after the part wax mold surface is coated with slurry, sand is hung, and the part mold shell with the embedded profiled heat preservation sheet is obtained after the wax is removed;

[0012] S5, smelting and pouring: the part mold shell with the embedded profiled heat preservation sheet is used for smelting and pouring process to pour the part, and the casting is formed;

[0013] S6, cleaning the surface of the part: removing the part mold shell and the profiled heat preservation sheet on the surface of the casting.

[0014] As a further scheme of the application, in step S1, the thickness of the profiled heat preservation sheet at different positions is determined according to the thermal conductivity of the profiled heat preservation sheet and the heat preservation condition required by the mounting position of the profiled heat preservation sheet on the surface of the part.

[0015] As a further scheme of the application, in step S6, the part mold shell and the profiled heat preservation sheet on the surface of the casting are removed by using a part mold shell removal method, and when the profiled heat preservation sheet cannot be removed by the part mold shell removal method, a ceramic core removal method is used to remove the profiled heat preservation sheet.

[0016] As a further scheme of the application, the cross section of the profiled heat preservation sheet is U-shaped, and a gas chamber is arranged on the side of the inner cavity of the profiled heat preservation sheet away from the opening, and the gas chamber is used to discharge the gas in the part mold shell during smelting and pouring.

[0017] As a further scheme of the application, the opening width of the gas chamber is 0.1-0.3mm.

[0018] As a further scheme of the application, the projection of the gas chamber in the length direction is funnel-shaped, and the width of the end of the gas chamber away from the inner cavity of the profiled heat preservation sheet is greater than the opening width.

[0019] As a further scheme of the application, the profiled 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 application, the profiled heat preservation sheet is made of a material with the same thermal expansion coefficient as the thermal expansion coefficient of the part mold shell.

[0021] As a further scheme of the application, the profiled heat preservation sheet is made of a rigid material.

[0022] As a further scheme of the present application, the profiled heat preservation sheet is made of a material with a lower thermal conductivity than that of the part shell.

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

[0024] 1. The present method wraps a profiled heat preservation sheet on the surface of the wax mold of the casting, and the profiled heat preservation sheet is used to heat preservation of the metal liquid in specific areas, so that the solidification sequence of the final metal liquid meets the expectation, and the casting based on precise temperature control is obtained, the columnar crystal growth environment is eliminated, and the heat preservation effect of the wrapped area of the profiled heat preservation sheet is improved, so that the metal liquid is cooled more slowly, the metal liquid has better flowability, and the problem of under-casting is improved.

[0025] 2. When the wax mold is produced, an installation groove for installing the profiled heat preservation sheet is reserved in the cavity of the wax mold, the profiled heat preservation sheet is placed in the installation groove and integrally formed with the part wax mold, then the part wax mold wrapped with the profiled heat preservation sheet is coated with slurry and sand is hung, so that the profiled heat preservation sheet is embedded in the inner cavity of the shell, the position of the profiled heat preservation sheet on the part wax mold is accurately controlled through the installation groove, then the profiled heat preservation sheet is embedded in the inner cavity of the part shell, the profiled heat preservation sheet is not moved during the whole process, the installation position of the final profiled heat preservation sheet is accurate, and when the final melting and pouring is performed, the metal liquid in the position where the profiled heat preservation sheet needs to be added can be accurately controlled in temperature, so as to accurately control the solidification sequence of the metal liquid, the solidification sequence of the final metal liquid meets the expectation, the casting based on precise temperature control is obtained, the quality of the final part is improved, and the product scrap rate is reduced. At the same time, the profiled heat preservation sheet is installed by using the present method, the profiled heat preservation sheet can be mass-produced, the installation of the profiled heat preservation sheet is more standardized, is not affected by manual errors of workers, the temperature field distribution of the metal liquid can be more accurately controlled, and the quality of the finally obtained casting is improved.

[0026] In addition to the objects, features, and advantages described above, the present application has other objects, features, and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application, and assist in the explanation of the application. In the drawings:

[0028] Figure 1 The flowchart of the present method.

[0029] Figure 2 The structure diagram of the profiled heat preservation sheet in the present method.

[0030] Figure 3 The schematic diagram of the blade wax mold pressing step in the present method.

[0031] Figure 4 Figure 1 is a schematic diagram of a wax mold of a part wrapped with a profiled heat preservation sheet.

[0032] Figure 5 Figure 2 is a schematic diagram of a wax mold of a turbine part.

[0033] Legend:

[0034] 1, profiled heat preservation sheet; 11, air chamber. DETAILED DESCRIPTION

[0035] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following description.

[0036] Please refer to Figures 1-5 The present application provides a technical solution: a method for solving the problems of columnar crystals and under-casting by using a wax mold wrapped with a profiled heat preservation sheet, which comprises the following steps:

[0037] S1, making a profiled heat preservation sheet 1: determining the shape and size of the profiled heat preservation sheet 1 according to the structure of the part, and making the profiled heat preservation sheet 1;

[0038] Determining the shape and size of the profiled heat preservation sheet 1 according to the structure of the part is a prior art, which is not described in detail here. The shape and size of the profiled heat preservation sheet 1 are designed according to the structure of the part, so that the profiled heat preservation sheet 1 can cover the area of the part surface where the profiled heat preservation sheet 1 is needed. Then, the profiled heat preservation sheet 1 is produced according to the obtained shape and size of the profiled heat preservation sheet 1;

[0039] Generally, the position of the part surface where the profiled heat preservation sheet 1 is needed is the thin-walled area of the part, so as to control the solidification sequence of the metal liquid during pouring;

[0040] S2, making a wax mold mold: making a wax mold mold according to the part wrapped with the profiled heat preservation sheet 1, so that the wax mold mold cavity contains an installation groove for installing the profiled heat preservation sheet 1;

[0041] When designing the wax mold mold, in order to make the profiled heat preservation sheet 1 and the part wax mold integrally formed, the position of the profiled heat preservation sheet 1 needs to be reserved in the wax mold mold cavity. Therefore, the part wrapped with the profiled heat preservation sheet 1 is used as the design basis of the wax mold mold cavity, so that the installation groove for pre-installing the profiled heat preservation sheet 1 is contained in the finally designed wax mold mold cavity. After the design of the wax mold mold is completed, the wax mold mold with the installation groove is produced according to the designed wax mold mold;

[0042] S3, blade wax mold pressing: placing the profiled heat preservation sheet 1 in the installation groove of the wax mold mold, and pressing the part wax mold through the wax mold mold to obtain the part wax mold wrapped with the profiled heat preservation sheet 1;

[0043] Before the wax mold of the part is pressed in the wax mold mold, first place the profiled heat preservation piece 1 in the position of the groove in the wax mold mold, fix the position of the profiled heat preservation piece 1 through the installation groove, then normally carry out the pressing process of the part wax mold, in the pressing process, the wax mold will slowly fill the cavity inside the wax mold mold, and directly contact with the profiled heat preservation piece 1 placed in the installation groove, after waiting for the part wax mold to solidify and form, open the wax mold mold, take out the part wax mold from the wax mold mold, at this time, the profiled heat preservation piece 1 is wrapped on the surface of the part wax mold, through reserving the position of the profiled heat preservation piece 1 in the wax mold mold in the design stage, it is ensured that the profiled heat preservation piece 1 can accurately wrap the position of the part surface which needs to add the profiled heat preservation piece 1;

[0044] S4, making part mold shell: after the part wax mold surface is coated with slurry, sand is hung, and the part mold shell with the profiled heat preservation piece 1 embedded is obtained after dewaxing;

[0045] After obtaining the part wax mold wrapped with the profiled heat preservation piece 1, the part mold shell can be made, in the process of making the part mold shell, the same method as the traditional process is adopted, after the part wax mold surface is coated with slurry, sand is hung to the designed thickness, and then the part mold shell is heated, so that the part wax mold in the part mold shell is melted, at this time, the profiled heat preservation piece 1 is wrapped in the part mold shell, and the part mold shell with the profiled heat preservation piece 1 in the inner cavity is obtained, since the profiled heat preservation piece 1 is positioned on the part wax mold through the installation groove, and then transferred to the inner cavity of the part mold shell, in this process, the profiled heat preservation piece 1 always keeps a fixed state, so that the position of the final profiled heat preservation piece 1 in the part mold shell is accurate;

[0046] S5, melting and pouring: the part mold shell with the profiled heat preservation piece 1 embedded is used for melting and pouring process to pour the part, and the casting is formed;

[0047] After obtaining the part mold shell with the profiled heat preservation piece 1 in the inner cavity, the melting and pouring process is carried out, and the molten metal material is delivered to the inner cavity of the part mold shell, in the cooling process of the metal liquid, the profiled heat preservation piece 1 can make the thin-walled area of the part have better heat preservation condition, reduce the temperature gradient between the thin-walled area of the part and other thick parts, eliminate the columnar crystal growth environment, so as to avoid the generation of columnar crystal, since the installation position of the profiled heat preservation piece 1 in the part mold shell is accurate, the profiled heat preservation piece 1 can be used for accurate temperature control of the thin-walled area of the part, accurate control of the solidification sequence of the metal liquid in the melting and pouring process, the effect of temperature control can be improved, and the product quality and the yield of the product can be improved;

[0048] S6, cleaning the surface of the part: removing the part mold shell and the profiled heat preservation piece 1 on the surface of the casting;

[0049] After the casting is obtained by melting and pouring, the part mold shell and the profiled heat preservation piece 1 on the surface of the casting need to be cleaned to obtain a clean casting.

[0050] After the part needs to add the area of the profiled heat preservation sheet 1, the profiled heat preservation sheet 1 is designed and produced, and it is ensured that the profiled heat preservation sheet 1 produced can accurately cover the area of the part surface where the profiled heat preservation sheet 1 needs to be added. At the same time, when the wax mold mold of the part is produced, the part wrapped with the profiled heat preservation sheet 1 is used as the design basis of the inner cavity of the wax mold mold. In this way, the mounting groove for placing the profiled heat preservation sheet 1 is contained in the inner cavity of the wax mold mold produced. When the part wax mold is pressed through the wax mold mold, the profiled heat preservation sheet 1 can be placed in the mounting groove in the inner cavity of the wax mold mold first, and then the part wax mold is pressed. The surface of the part wax mold finally pressed into shape is wrapped with the profiled heat preservation sheet 1. Since the inner cavity of the wax mold mold is designed according to the part wrapped with the profiled heat preservation sheet 1, the wrapping position of the profiled heat preservation sheet 1 on the part wax mold obtained finally is very accurate. Then, the part wax mold wrapped with the profiled heat preservation sheet 1 is used to make a part mold shell. The profiled 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 since the profiled heat preservation sheet 1 is transferred from the part wax mold to the part mold shell through the part mold shell manufacturing process, it can be ensured that the profiled heat preservation sheet 1 is accurately transferred to the inner cavity wall of the part mold shell. When finally melting and pouring, the metal liquid at the position of the part where the profiled heat preservation sheet 1 needs to be added can be accurately controlled in temperature to accurately control the solidification sequence of the metal liquid, so that the solidification sequence of the metal liquid finally meets the expectation, and a casting based on accurate temperature control is obtained. The quality of the final part is improved, and the product scrap rate is reduced.

[0051] At the same time, the installation of the profiled heat preservation sheet 1 by the method can mass-produce the profiled heat preservation sheet 1, and the installation of the profiled heat preservation sheet 1 is more standardized and is not affected by manual errors of workers. The temperature field distribution of the metal liquid can be more accurately controlled, and the quality of the casting obtained finally is improved.

[0052] Further, in step S1, the thickness of the profiled heat preservation sheet 1 at different positions is determined according to the thermal conductivity of the profiled heat preservation sheet 1 and the heat preservation condition required by the installation position of the profiled heat preservation sheet 1 on the part surface.

[0053] As shown in Figure 2 When the profiled heat preservation sheet 1 is installed on the exhaust edge of the blade in the turbine part, the blade wall thickness gradually decreases towards the exhaust edge. Therefore, when designing the profiled heat preservation sheet 1, the wall thickness of the profiled heat preservation sheet 1 gradually increases in the same direction. The thickness of the profiled heat preservation sheet 1 in the area with small wall thickness is greater, so as to obtain better heat preservation effect and reduce the temperature gradient caused by the wall thickness difference.

[0054] In step S6, the part shell removal method is used to remove the part shell and the profiled heat preservation piece 1. When the profiled heat preservation piece 1 cannot be removed by the part shell removal method, the ceramic core stripping method is used to remove the profiled heat preservation piece 1. After the casting of the part is obtained by cooling the molten metal, the part shell on the surface of the casting needs to be cleaned. When the part shell is cleaned, the traditional part shell removal method is first used to remove the part shell on the surface of the casting. When the profiled heat preservation piece 1 cannot be removed by the part shell removal method, the ceramic core stripping method can be used to remove the profiled heat preservation piece 1.

[0055] Figures 2-5 An embodiment is disclosed. In the 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 edge and the intake edge of the blade, columnar crystals perpendicular to the stress direction often appear on the exhaust edge of the blade, resulting in the rejection of the casting. Therefore, a heat preservation patch needs to be added at the exhaust edge position of the turbine component to reduce the heat dissipation speed of the molten metal at the exhaust edge position of the turbine component, reduce the temperature gradient between the exhaust edge of the turbine component and the thick part, eliminate the columnar crystal growth environment, and thus avoid columnar crystals. Therefore, the profiled heat preservation piece 1 is designed as a long strip with a U-shaped cross section, as shown in FIG. 1, and is used to wrap the exhaust edge of the turbine component. In the embodiment, the turbine component needs to be split into multiple modules for wax mold forming due to the relatively complex structure of the turbine component. Then, the module wax molds are spliced to form an overall turbine component wax mold. The profiled heat preservation piece 1 is arranged at the exhaust edge of the blade in the turbine component. At the same time, when the wax mold of the turbine component is split, the blade in the turbine component is split into single unit blade modules. Therefore, when designing the wax mold mold of the unit blade, the blade unit wrapped with the profiled heat preservation piece 1 needs to be taken as the design basis to design the wax mold mold of the unit blade, as shown in FIG. 2. The internal cavity of the final unit blade wax mold contains a cavity for forming the unit blade and a mounting groove for accommodating the profiled heat preservation piece 1. When the unit blade is formed by the unit blade wax mold, the profiled heat preservation piece 1 is first placed in the mounting groove in the internal cavity of the wax mold mold. Then, the unit blade wax mold is pressed, as shown in FIG. 3, so that the exhaust edge position of the finally formed unit blade wax mold is wrapped by the profiled heat preservation piece 1. Then, the unit blade wax mold is spliced with the remaining module wax molds, as shown in FIG. 4. Figure 2 Figure 3 Figure 4 Figure 5 ​​​The turbine part wax mold is shown, at this time, the exhaust edge of the turbine part wax mold is entirely wrapped with the profiled heat preservation sheet 1, and the profiled heat preservation sheet 1 is accurately positioned, then the turbine part wax mold is coated with slurry and hung with sand by using a traditional process, and after dewaxing, a turbine part part mold shell with the profiled heat preservation sheet 1 embedded is obtained, at this time, the profiled heat preservation sheet 1 is arranged at the position of the exhaust edge in the inner cavity of the turbine part part mold shell, the profiled heat preservation sheet 1 can strengthen the heat preservation effect of the position of the exhaust edge in the subsequent melting and pouring process, so as to reduce the temperature ladder of the molten metal at the position of the exhaust edge and the molten metal at other thick and large areas, eliminate the columnar crystal growth environment, thereby avoiding the columnar crystal, and the installation position of the profiled heat preservation sheet 1 is accurate, so that the quality of the final casting can be effectively improved, and the casting rejection rate can be reduced.

[0056] Preferably, a gas chamber 11 is arranged on the side of the inner cavity of the profiled heat preservation sheet 1 away from the opening, the gas chamber 11 is used for discharging the gas in the part mold shell during the melting and pouring process, preventing the gas from being trapped during the metal liquid filling process, and preventing the exhaust edge position of the turbine part from being undercast;

[0057] Since the profiled heat preservation sheet 1 is generally arranged at the thin-walled area of the part, such as Figures 2-3 As shown, when the profiled heat preservation sheet 1 is used to be arranged at the exhaust edge position of the turbine part, the exhaust edge position of the blade is thin-walled, and thus prone to undercast caused by gas trapping, therefore, the gas chamber 11 can be arranged on the side of the inner side of the profiled heat preservation sheet 1 away from the opening, the gas chamber 11 can be used to accommodate air, if there is residual gas in the part mold shell during the pouring process, the gas can be extruded into the gas chamber 11 by the molten metal, preventing the gas from being trapped in the part mold shell to cause gas trapping, the gas chamber 11 is arranged in the inner cavity of the profiled heat preservation sheet 1, and does not belong to the part, so that the gas discharged into the gas chamber 11 is equivalent to the gas discharged from the part mold shell, so that the gas no longer affects the complete formation of the exhaust edge, and the undercast problem of the exhaust edge is solved.

[0058] Further, the opening width of the gas chamber 11 is 0.1-0.3mm, which is used to prevent the molten metal from entering the gas chamber 11 and prevent the molten metal from transitional filling;

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

[0060] Further, the projection of the gas chamber 11 in the length direction is in the shape of a funnel, the width of the end of the gas chamber 11 away from the inner cavity of the profiled heat preservation sheet 1 is greater than the opening width, so that the space for accommodating the gas in the gas chamber 11 is increased, and the gas chamber 11 can accommodate more gas.

[0061] The profiled heat preservation sheet 1 is made of a material with a surface friction coefficient smaller than that of the part shell, so as to reduce the friction resistance of the molten metal in the profiled heat preservation sheet 1, and facilitate the filling of the molten metal.

[0062] When the profiled heat preservation sheet 1 is arranged at the exhaust edge of the turbine part, the wall thickness of the exhaust edge is small, and the molten metal is subjected to large friction resistance during the filling, which is not conducive to the filling of the molten metal. After the profiled heat preservation sheet 1 is arranged in the part shell, the profiled heat preservation sheet 1 directly contacts the molten metal. By controlling the material of the profiled heat preservation sheet 1, the surface friction coefficient of the profiled heat preservation sheet 1 is smaller than that of the part shell. Thus, when the molten metal fills the exhaust edge region of the blade, the molten metal contacts the profiled heat preservation sheet 1. Compared with the conventional part shell, the molten metal is subjected to smaller friction resistance when contacting the profiled heat preservation sheet 1, which is more conducive to the filling of the molten metal, thereby further reducing the probability of underfilling.

[0063] The profiled heat preservation sheet 1 is made of a material with the same thermal expansion coefficient as that of the part shell, so as to ensure that the size changes of the part shell and the profiled heat preservation sheet 1 are consistent during the heating process, and avoid that the profiled heat preservation sheet 1 expands and cracks the external part shell or shakes due to unstable positioning.

[0064] During the smelting and pouring process, the part shell and the profiled heat preservation sheet 1 need to be heated. When the thermal expansion coefficient of the profiled heat preservation sheet 1 is consistent with that of the part shell, the profiled heat preservation sheet 1 and the part shell can always be closely matched during the heating process, so as to prevent the profiled heat preservation sheet 1 from expanding and cracking the external part shell due to large size change, and also prevent the part shell from having a large size change and generating a gap with the profiled heat preservation sheet 1. When there is no material with the same thermal expansion coefficient as that of the part shell, a material with the closest thermal expansion coefficient to that of the part shell is used under the premise of meeting other performance requirements.

[0065] Preferably, the profiled heat preservation sheet 1 is made of a rigid material, so as to ensure that the profiled heat preservation sheet 1 can be stably placed in the mounting groove of the wax mold, and also ensure that the profiled heat preservation sheet 1 does not deform during the pressing of the part wax mold and the making of the part shell, so as to ensure the size accuracy of the finally formed casting.

[0066] Preferably, the profiled heat preservation sheet 1 is made of a material with a lower thermal conductivity than that of the part shell, so as to make the heat preservation effect of the profiled heat preservation sheet 1 better than that of the part shell, and ensure that the heat preservation effect of the region surrounding the profiled heat preservation sheet 1 is better during the pouring process, so as to reduce the temperature gradient caused by the wall thickness during the cooling of the molten metal.

[0067] Preferably, the profiled heat preservation piece 1 is made of the same high-temperature ceramic material as the ceramic core, and the manufacturing process is the same as the current manufacturing process of the ceramic core. Since the ceramic core has been widely used in the field of smelting and pouring, the material performance has been verified in practice, the production process is relatively perfect, and the method for removing the profiled heat preservation piece 1 at the end is also more perfect. The profiled heat preservation piece 1 on the surface of the casting can be accurately removed, and the material research and development cost can be reduced.

[0068] The preferred embodiments of the present application have been described above, but the present application is not limited to the above. Various modifications and changes can be made by those skilled in the art based on the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of wax pattern wrapping contouring insulating sheet for solving columnar crystal and undercasting problem, characterized in that, The method comprises the following steps: S1, making a profiled heat preservation piece (1): determining the shape and size of the profiled heat preservation piece (1) according to the structure of the part, and making the profiled heat preservation piece (1); S2, making a wax mold: making a wax mold according to the part wrapped with the profiled heat preservation piece (1), so that the wax mold cavity contains an installation groove for installing the profiled heat preservation piece (1); S3, blade wax mold pressing: placing the profiled heat preservation piece (1) in the installation groove of the wax mold, and pressing the part wax mold through the wax mold to obtain a part wax mold wrapped with the profiled heat preservation piece (1); S4, making a part mold shell: after coating, sanding and dewaxing on the surface of the part wax mold, a part mold shell with the profiled heat preservation piece (1) embedded is obtained; S5, melting and pouring: using the part mold shell with the profiled heat preservation piece (1) embedded to perform melting and pouring process to pour the part, and form a casting; S6, cleaning the surface of the part: removing the part mold shell and the profiled heat preservation piece (1) on the surface of the casting. The cross section of the profiled heat preservation piece (1) is U-shaped, and a gas chamber (11) is arranged on the side of the inner cavity of the profiled heat preservation piece (1) away from the opening, and the gas chamber (11) is used for discharging gas in the part mold shell during the melting and pouring process.

2. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: In step S1, the thickness of the profiled heat preservation piece (1) at different positions is determined according to the thermal conductivity coefficient of the profiled heat preservation piece (1) and the heat preservation condition required by the installation position of the profiled heat preservation piece (1) on the surface of the part.

3. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: In step S6, the part mold shell removal method is used to remove the part mold shell and the profiled heat preservation piece (1) on the surface of the casting, and when the profiled heat preservation piece (1) cannot be removed by the part mold shell removal method, the ceramic core stripping method is used to remove the profiled heat preservation piece (1).

4. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: The opening width of the gas chamber (11) is 0.1-0.3mm.

5. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercuts according to claim 4, characterized in that: The projection of the gas chamber (11) in the length direction is funnel-shaped, and the width of the gas chamber (11) away from the inner cavity of the profiled heat preservation piece (1) is greater than the opening width.

6. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: The profiled heat preservation piece (1) is made of a material with a surface friction resistance less than the surface friction coefficient of the part mold shell.

7. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: The profiled heat preservation piece (1) is made of a material with the same thermal expansion coefficient as the part mold shell.

8. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: The profiled heat preservation piece (1) is made of a rigid material.

9. A method of using a wax pattern wrapping profiled heat shield for solving the problem of columnar crystals and undercoring according to claim 1, characterized in that: The profiled heat preservation piece (1) is made of a material with a lower thermal conductivity than the part mold shell.

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