Composite casting mold and titanium alloy cylindrical part casting method
By using composite casting and vacuum smelting casting technology, the quality problems such as insufficient pouring, cold partition, and pores that are prone to occur during the casting process of high-strength titanium alloy cylindrical parts are achieved, and high-quality and low-defect casting of titanium alloy cylindrical parts are achieved.
Patent Information
- Application Number
- CN202411710334.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-07
AI Technical Summary
Due to the high degree of alloying and poor liquid metal flow performance, the cast cylindrical parts cast in existing casting solutions are prone to quality problems such as insufficient pouring, cold partitions, and pores.
Composite casting molds are adopted, including metal base plates, special-shaped metal outer molds, flat metal outer molds, metal cover plates and ceramic cores. Through vacuum smelting and casting technology, the defects of casting are eliminated and the mechanical properties and surface quality of castings are improved.
Through this method, the casting quality of the cylindrical titanium alloy can be improved, defects can be reduced, mechanical properties and surface accuracy can be improved, and mold cost can be reduced.
Smart Images
Figure CN119566224A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of material casting, and in particular to a composite casting mold and a titanium alloy cylindrical part casting method. Background Art
[0002] Titanium alloys have the characteristics of high specific strength, good impact resistance, corrosion resistance, and heat resistance, and are widely used in weapon equipment, aviation industry, shipbuilding industry, nuclear industry, marine engineering, etc. As the performance requirements of various equipment become higher and higher, the performance requirements of titanium alloy cylindrical parts are correspondingly increased.
[0003] However, due to the high degree of alloying, high-strength titanium alloys have poor molten metal flow properties, and cylindrical parts cast using existing casting schemes are prone to quality problems such as insufficient pouring, cold shut, and air holes. Summary of the invention
[0004] The embodiments of the present application provide a composite casting mold and a titanium alloy cylindrical part casting method to improve the casting quality of the titanium alloy cylindrical part.
[0005] In a first aspect, an embodiment of the present application provides a composite casting mold, including a metal base plate, a special-shaped metal outer mold, a flat metal outer mold, a metal cover plate, and a ceramic core;
[0006] The special-shaped metal outer mold, the flat metal outer mold and the ceramic core are sequentially mounted on the metal bottom plate, and the special-shaped metal outer mold and the flat metal outer mold are enclosed on the outside of the ceramic core;
[0007] The metal cover plate is disposed on the special-shaped metal outer mold and the flat metal outer mold to enclose the ceramic core in a closed space.
[0008] In a feasible implementation, the composite casting mold further includes a ceramic riser cover plate, and the ceramic riser cover plate is arranged between the ceramic core and the metal cover plate.
[0009] In a feasible implementation, the composite casting mold further includes a plurality of ceramic risers, and the plurality of ceramic risers are respectively arranged on the special-shaped metal outer mold and the flat metal outer mold.
[0010] In a feasible implementation, the metal base plate, the special-shaped metal outer mold, the flat metal outer mold and the metal cover plate are all sprayed with heat-resistant paint.
[0011] In a second aspect, an embodiment of the present application provides a method for casting a titanium alloy cylindrical part, using the composite casting mold as described in the first aspect to cast the titanium alloy cylindrical part, comprising:
[0012] Design and manufacture composite casting molds, including designing ceramic risers and runners; determining the parting surfaces of inner and outer molds, and preparing metal base plates, special-shaped metal outer molds, flat metal outer molds, metal cover plates, and ceramic cores;
[0013] Processing and assembling composite casting molds;
[0014] Vacuum melting and pouring;
[0015] Titanium alloy barrels are unpacked and processed.
[0016] In a feasible implementation, the processing and assembling of the composite casting mold includes:
[0017] The metal base plate, the special-shaped metal outer mold, the flat metal outer mold and the metal cover plate are sprayed with heat-resistant coating and dried for 2 hours, the special-shaped metal outer mold, the flat metal outer mold and the ceramic core are installed on the metal base plate through slots and assembly steps, the ceramic riser cover plate is snapped onto the ceramic core, the metal cover plate is installed on the special-shaped metal outer mold and the flat metal outer mold, and then the ceramic risers are installed on the special-shaped metal outer mold and the flat metal outer mold to complete the assembly of the composite casting.
[0018] In a feasible implementation, the assembled composite casting mold is kept at 500° C. for 2 h to 4 h.
[0019] In a feasible implementation, the vacuum melting and pouring includes:
[0020] A vacuum consumable electrode arc skull furnace is used to automatically melt the titanium alloy ingot and pour it into the composite casting mold, and a vacuum environment is maintained and the casting is waited to cool to room temperature.
[0021] In a feasible implementation, the titanium alloy cylindrical part is unpacked and processed, including:
[0022] The titanium alloy cylindrical part is taken out from the composite casting mold, and is sequentially subjected to cutting, ceramic pouring, hot isostatic pressing, pickling, repair welding and grinding.
[0023] The embodiment of the present application provides a composite casting mold and a titanium alloy cylindrical casting method, wherein the composite casting mold includes a metal base plate, a special-shaped metal outer mold, a flat metal outer mold, a metal cover plate and a ceramic core. The special-shaped metal outer mold, the flat metal outer mold and the ceramic core are sequentially mounted on the metal base plate, and the special-shaped metal outer mold and the flat metal outer mold are enclosed on the outside of the ceramic core; the metal cover plate is arranged on the special-shaped metal outer mold and the flat metal outer mold to enclose the ceramic core in a closed space.
[0024] The outer surface dimensional accuracy of the composite casting of the metal outer mold and the ceramic core is higher, and the utilization rate is high, and the mold cost is lower. In addition, the preheating temperature of the metal outer mold is high, and the titanium alloy liquid is not quenched during pouring, which can eliminate the defect of insufficient pouring of the casting; the metal outer mold has good heat transfer ability, and the metal liquid after filling can be evenly and quickly cooled, and the casting has finer grains and better mechanical properties; during the reuse of the metal outer mold, bumps will not cause damage to the outer mold, and bump marks can be eliminated after spraying heat-resistant coatings, and will not cause slag inclusions and surface flow marks in the casting. A method for casting titanium alloy cylindrical parts uses the composite casting mold as described in the first aspect to cast titanium alloy cylindrical parts, and the cast titanium alloy cylindrical parts have fewer defects and higher quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present application and do not constitute improper limitations on the present invention.
[0026] In the attached picture:
[0027] Figure 1 is a schematic structural diagram of a composite casting mold provided in one embodiment of the present application;
[0028] Figure 2 It is a schematic flow chart of a titanium alloy cylindrical component casting method provided in one embodiment of the present application.
[0029] Description of reference numerals:
[0030] 100-metal base plate; 200-special-shaped metal outer mold; 300-flat metal outer mold; 400-metal cover plate; 500-ceramic core; 600-ceramic riser cover plate; 700-ceramic riser. DETAILED DESCRIPTION
[0031] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.
[0032] In the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.
[0033] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0034] Titanium alloys have the characteristics of high specific strength, good impact resistance, corrosion resistance, and heat resistance, and are widely used in weapon equipment, aviation industry, shipbuilding industry, nuclear industry, marine engineering, etc. As the performance requirements of various equipment become higher and higher, the performance requirements of titanium alloy cylindrical parts are correspondingly increased.
[0035] However, due to the high degree of alloying, high-strength titanium alloys have poor molten metal flow properties, and cylindrical parts cast using existing casting schemes are prone to quality problems such as insufficient pouring, cold shut, and air holes.
[0036] In order to solve the above problems, the embodiment of the present application provides a composite casting mold and a titanium alloy cylindrical part casting method. The solution provided in the embodiment of the present application will be described in detail below in conjunction with the drawings in the specification.
[0037] Figure 1 It is a schematic diagram of the structure of a composite casting mold provided in one embodiment of the present application.
[0038] Reference Figure 1 As shown, in the first aspect, the embodiment of the present application provides a composite casting mold and a titanium alloy cylindrical casting method, wherein the composite casting mold includes a metal base plate 100, a special-shaped metal outer mold 200, a flat metal outer mold 300, a metal cover plate 400 and a ceramic core 500. The special-shaped metal outer mold 200, the flat metal outer mold 300 and the ceramic core 500 are sequentially installed on the metal base plate 100, and the special-shaped metal outer mold 200 and the flat metal outer mold 300 are enclosed on the outside of the ceramic core 500; the metal cover plate 400 is arranged on the special-shaped metal outer mold 200 and the flat metal outer mold 300 to enclose the ceramic core 500 in a closed space.
[0039] It should be noted that the metal base plate 100, the special-shaped metal outer mold 200, the flat metal outer mold 300, and the metal cover plate 400 are made of metal, such as QT500-7. The ceramic core 500 is made of ceramic, which can be a ceramic core 500 with an yttrium oxide surface layer.
[0040] It is understandable that the buckling design of the special-shaped metal outer mold 200 and the flat metal outer mold 300 facilitates the mold opening when the casting is unpacked, and the parting surface is located in the processable area outside the casting, and the parting line will not cause the surface quality of the casting to decrease. Of course, the metal outer mold can also be designed as a left-right symmetrical opening and closing structure.
[0041] The outer surface dimensional accuracy of the metal outer mold and the ceramic core 500 composite mold is higher, the utilization rate is high, and the mold cost is lower. In addition, the preheating temperature of the metal outer mold is high, and the titanium alloy liquid is not quenched during pouring, which can eliminate the defect of insufficient pouring of the casting; the metal outer mold has good heat transfer ability, and the metal liquid after filling can be evenly and quickly cooled, and the casting has finer grains and better mechanical properties; during the repeated use of the metal outer mold, bumps will not cause damage to the outer mold, and bump marks can be eliminated after spraying heat-resistant coatings, which will not cause slag inclusions and surface flow marks in the casting.
[0042] Continue to refer to Figure 1 As shown, the composite mold further includes a ceramic riser cover plate 600, which is disposed between the ceramic core 500 and the metal cover plate 400. The composite mold further includes a plurality of ceramic risers 700, which are respectively disposed on the special-shaped metal outer mold 200 and the flat metal outer mold 300. The ceramic risers 700 can be provided with a plurality of vent holes to ensure that when the titanium alloy metal liquid is filled into the mold, the residual gas in the composite mold is discharged in time to avoid the defect of insufficient casting caused by holding the air.
[0043] The ceramic riser 700 can prevent shrinkage cavities from forming in the casting. When the casting is formed, the molten metal in the cavity of the ceramic riser 700 replenishes the casting, compensating for the liquid shrinkage of the molten metal in the cavity and the shrinkage of the casting during solidification, so as to obtain a dense casting without shrinkage cavities. In addition, during pouring, a large amount of gas in the cavity can be smoothly discharged out of the mold through the ceramic riser 700, reducing the porosity defects in the casting.
[0044] In addition, in some examples, the metal base plate 100, the special-shaped metal outer mold 200, the flat metal outer mold 300 and the metal cover plate 400 are all sprayed with heat-resistant coating. It is understandable that the heat-resistant coating can fill the gaps on the surface of the sand mold and the sand core, and establish a fire-resistant barrier between the mold and the molten metal to avoid mechanical sand adhesion, chemical sand adhesion and surface roughness of the casting, and improve the surface quality of the casting. In addition, the use of heat-resistant coating can reduce the burrs of the casting caused by surface cracking of the sand mold or sand core, reduce the sand blasting, sand loss and sand holes caused by insufficient surface strength of the sand mold (core), and reduce the carbon increase, sulfur increase, phosphorus increase and subcutaneous pores caused by nitrogen in the casting due to the use of resin sand. At the same time, the heat-resistant coating can also protect the mold and extend the service life.
[0045] Figure 2 It is a schematic flow chart of a titanium alloy cylindrical component casting method provided in one embodiment of the present application.
[0046] Reference Figure 2 As shown, in a second aspect, an embodiment of the present application provides a method for casting a titanium alloy cylindrical part, using the composite casting mold as described in the first aspect to cast the titanium alloy cylindrical part, comprising:
[0047] S100: Design and manufacture composite castings, including designing ceramic risers and runners; determining the parting surfaces of inner and outer molds, and preparing metal base plates, special-shaped metal outer molds, flat metal outer molds, metal cover plates, and ceramic cores.
[0048] For example, the shrinkage rate can be set at 0.45% to 0.7% according to the size characteristics of the titanium alloy cylindrical part and the metal properties of the titanium alloy, and the ceramic riser and runner can be designed according to the structural characteristics of the casting. A diverter runner can be set at the large end face of the casting, a straight runner can be set at the center of the cylindrical position of the casting, and a ceramic riser can be set at the thick part of the casting; the inner and outer mold parting surfaces can be determined according to the surface characteristics of the casting.
[0049] S200: Processing and assembling composite castings.
[0050] Exemplarily, processing and assembling the composite mold includes:
[0051] The metal base plate, the special-shaped metal outer mold, the flat metal outer mold and the metal cover plate are sprayed with heat-resistant paint and dried for 2 hours, the special-shaped metal outer mold, the flat metal outer mold and the ceramic core are installed on the metal base plate through the slots and assembly steps, the ceramic riser cover plate is buckled on the ceramic core, the metal cover plate is installed on the special-shaped metal outer mold and the flat metal outer mold, and then the ceramic riser is installed on the special-shaped metal outer mold and the flat metal outer mold to assemble the composite mold. The assembled composite mold is kept at 500°C for 2h-4h.
[0052] S300: Vacuum melting and pouring.
[0053] Exemplarily, the vacuum melting and pouring comprises: automatically melting the titanium alloy ingot in a vacuum consumable electrode arc skull furnace and pouring it into the composite casting mold, maintaining a vacuum environment and waiting for the casting to cool to room temperature.
[0054] S400: Titanium alloy cylinder is unpacked and processed to cast the titanium alloy cylinder.
[0055] The titanium alloy cylindrical parts are unpacked and processed, including: first cleaning the ceramic riser, then removing the metal base plate and metal cover plate, using the tooling on the demoulding mechanism to open the special-shaped metal outer mold and the flat metal outer mold, and finally cleaning the ceramic core and the ceramic riser cover plate to obtain the casting blank. The metal base plate, special-shaped metal outer mold, flat metal outer mold and metal cover plate must all be cleaned of heat-resistant coating and properly maintained. After the titanium alloy cylindrical blank is taken out of the composite casting mold, it is cut and poured with ceramic risers, hot isostatic pressing, pickling, repair welding and grinding are carried out in sequence to finally obtain the titanium alloy cylindrical parts.
[0056] Example
[0057] Casting situation: The cylindrical titanium alloy cylinder is made of ZTC4, with a diameter of Φ450mm, a height of 710mm, a main wall thickness of 6mm, flanges at both ends with thicknesses of 20mm and 38mm respectively, and bosses and features of varying heights distributed in the inner cavity. The number of castings is 50.
[0058] The casting steps are as follows:
[0059] (1) Design and manufacture of molds. The shrinkage rate was set to 0.6% according to the size characteristics of the titanium alloy cylindrical parts and the metal properties of the titanium alloy. The ceramic riser and runner were designed according to the structural characteristics of the casting. A diverter runner was set on the 38 mm thick flange surface of the casting, a straight runner was set at the center of the casting, and a ceramic riser was set on the 20 mm thick flange surface of the casting. The outer mold was determined to be a symmetrical open structure according to the surface characteristics of the casting. The metal outer mold made of QT500-7 and the ceramic core with an yttria surface layer were prepared.
[0060] (2) Casting mold preparation: spray the metal base plate, special-shaped metal outer mold, flat metal outer mold and metal cover plate with heat-resistant coating and dry them for 2 hours. Install the special-shaped metal outer mold, flat metal outer mold and ceramic core on the metal base plate through slots and assembly steps. Then install the ceramic riser cover plate and metal cover plate. Finally, fix the composite mold with tooling to realize the assembly of the titanium alloy cylindrical composite mold. The assembled composite mold is kept at 500°C for 3 hours.
[0061] (3) Vacuum melting and pouring: When the composite casting mold is loaded into the furnace, the temperature is higher than 400°C. A vacuum consumable electrode arc shell furnace is used to automatically melt 130 kg of titanium alloy ingots and pour them into the composite casting mold. The vacuum environment is maintained and the casting is waited for to cool to room temperature.
[0062] (4) Unpack the castings, open the furnace door and fork out the castings. After removing the metal bottom plate and metal cover plate, use the tooling on the demoulding mechanism to open the special-shaped metal outer mold and the flat metal outer mold. Finally, clean the ceramic core and ceramic riser cover plate to obtain the casting blank. The metal bottom plate, special-shaped metal outer mold, flat metal outer mold and metal cover plate must be cleaned of the heat-resistant coating and properly maintained.
[0063] (5) Casting circulation: the titanium alloy cylindrical blank can be obtained through cutting, pouring ceramic riser, hot isostatic pressing, pickling, repair welding, grinding, inspection and other processes to obtain qualified castings.
[0064] It is easy to understand that those skilled in the art can combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments based on the several embodiments provided in the present application, and these embodiments do not exceed the protection scope of the present application.
[0065] The above specific implementation methods further explain in detail the purpose, technical solutions and beneficial effects of the embodiments of the present application. It should be understood that the above are only specific implementation methods of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.
Claims
1. A composite casting mold, characterized in that: It includes a metal base plate, a special-shaped metal outer mold, a flat metal outer mold, a metal cover plate and a ceramic core; The special-shaped metal outer mold, the flat metal outer mold and the ceramic core are sequentially mounted on the metal bottom plate, and the special-shaped metal outer mold and the flat metal outer mold are enclosed on the outside of the ceramic core; The metal cover plate is disposed on the special-shaped metal outer mold and the flat metal outer mold to enclose the ceramic core in a closed space.
2. The composite mold according to claim 1, characterized in that: The composite casting mold further comprises a ceramic riser cover plate, wherein the ceramic riser cover plate is arranged between the ceramic core and the metal cover plate.
3. The composite mold according to claim 1, characterized in that: The composite casting mold further comprises a plurality of ceramic risers, which are respectively arranged on the special-shaped metal outer mold and the flat metal outer mold.
4. The composite mold according to claim 1, characterized in that: The metal bottom plate, the special-shaped metal outer mold, the flat metal outer mold and the metal cover plate are all sprayed with heat-resistant paint.
5. A method for casting a titanium alloy cylindrical part, characterized in that: The method of casting a titanium alloy cylindrical part using the composite casting mold as described in any one of claims 1 to 4 comprises: Design and manufacture composite casting molds, including designing ceramic risers and runners; determining the parting surfaces of inner and outer molds, and preparing metal base plates, special-shaped metal outer molds, flat metal outer molds, metal cover plates, and ceramic cores; Processing and assembling composite casting molds; Vacuum melting and pouring; Titanium alloy barrels are unpacked and processed.
6. The titanium alloy cylindrical casting method according to claim 5, characterized in that: The processing and assembling of the composite casting mold comprises: The metal base plate, the special-shaped metal outer mold, the flat metal outer mold and the metal cover plate are sprayed with heat-resistant coating and dried for 2 hours, the special-shaped metal outer mold, the flat metal outer mold and the ceramic core are installed on the metal base plate through slots and assembly steps, the ceramic riser cover plate is snapped onto the ceramic core, the metal cover plate is installed on the special-shaped metal outer mold and the flat metal outer mold, and then the ceramic risers are installed on the special-shaped metal outer mold and the flat metal outer mold to complete the assembly of the composite casting.
7. The titanium alloy cylindrical casting method according to claim 6, characterized in that: The assembled composite mold is kept at 500°C for 2h-4h.
8. The titanium alloy cylindrical casting method according to claim 5, characterized in that: The vacuum melting and pouring comprises: A vacuum consumable electrode arc skull furnace is used to automatically melt the titanium alloy ingot and pour it into the composite casting mold, and a vacuum environment is maintained and the casting is waited to cool to room temperature.
9. The titanium alloy cylindrical casting method according to claim 5, characterized in that: The titanium alloy cylindrical part is unpacked and processed, including: The titanium alloy cylindrical part is taken out from the composite casting mold, and is sequentially subjected to cutting, ceramic pouring, hot isostatic pressing, pickling, repair welding and grinding.