Plum blossom test bar casting shell for stainless steel

Abstract

The utility model provides a quincunx test bar casting shell for stainless steel, which relates to the technical field of casting shells and comprises a disc, a plurality of sprue gates are arranged on the disc, a casting cup is connected above the disc, the lower portions of the sprue gates are respectively connected with the upper ends of quincunx test bar casting heads, and the upper ends of the quincunx test bar casting heads are connected with the disc. The lower end of the plum blossom test bar casting head is connected with a casting shell, and a casting cavity is formed in the casting shell. According to the quincunx test bar casting shell for stainless steel, seven quincunx test bars are cast simultaneously through vacuum remelting of a 50 kg vacuum induction furnace, the cast quincunx test bars are good in solidification structure, and the edges of the quincunx test bars are free of obvious shrinkage porosity and shrinkage cavities.

Description

Technical Field

[0001] The utility model relates to the technical field of casting shells, in particular to a plum blossom test bar casting shell for stainless steel. Background Art

[0002] Maraging stainless steel is a classic, hardenable cast steel. Through appropriate heat treatment processes, it achieves an excellent combination of strength, toughness, corrosion resistance, and oxidation resistance. It is widely used in aerospace, marine engineering, and nuclear power equipment. Fe-Cr-Ni-Co-Mo maraging stainless steel for precision casting can be used to manufacture key pressure-bearing components of liquid oxygen / kerosene high-pressure secondary combustion engines, such as the centrifugal wheel, low-pressure casing, and liquid oxygen main valve casing of turbo oxygen pumps. Due to the large shrinkage rate of stainless steel during solidification, significant shrinkage defects often occur during the casting process, such as at the center of the plum blossom test bar (where the molten steel last solidified). To eliminate the influence of casting density on the material's mechanical properties, mechanical property testing of maraging stainless steel castings is typically performed by sampling at the edge of the plum blossom test bar.

[0003] The utility model patent application number CN201320229075.8 discloses a mold shell for a plum blossom test bar for high-temperature alloys, but does not mention its suitability for casting stainless steel plum blossom test bars.

[0004] The utility model is based on the actual situation of the 50kg vacuum induction furnace equipped by Chengdu Advanced Metal Materials Industry Technology Research Institute Co., Ltd., and develops a stainless steel plum blossom test rod casting shell that matches the furnace body. One vacuum melting can cast 7 plum blossom test rods. Utility Model Content

[0005] The utility model provides a plum blossom test bar casting mold shell for stainless steel, which fills the technical problem of the blank of the existing stainless steel plum blossom test bar casting technology.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A stainless steel plum blossom test rod casting mold shell comprises a circular disc with a plurality of pouring ports provided on the circular disc. The upper portion of the circular disc is connected to a pouring cup, the lower portions of the pouring ports are respectively connected to the upper ends of plum blossom test rod pouring risers, the lower ends of the plum blossom test rod pouring risers are connected to a casting shell, and a casting cavity is provided inside the casting shell.

[0008] Furthermore, a surface layer shell is provided on the outer side of the casting shell, and a reinforcement layer is provided on the outer side of the surface layer shell.

[0009] Furthermore, the pouring gate is circular, the interior of the pouring gate is plum blossom-shaped, and the interior of the casting cavity is plum blossom-shaped.

[0010] Furthermore, the surface shell is made of silica sol zircon powder coating, and the zircon powder is powder; the coating and material-powder ratio of the surface shell is 3.0-3.4.

[0011] Furthermore, the reinforcement layer uses silica sol mullite powder as coating, and mullite powder as powder; the coating to powder ratio of the reinforcement layer is 2.8-3.6.

[0012] Furthermore, seven pouring ports are symmetrically distributed on the disc.

[0013] The beneficial effects of the present invention are:

[0014] The utility model prepares a stainless steel plum blossom test bar casting shell, which is vacuum remelted in a 50kg vacuum induction furnace and simultaneously cast with 7 plum blossom test bars. The cast plum blossom test bars have good solidification structure and no obvious shrinkage cavities on the edges of the plum blossom test bars. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a schematic diagram of the disc structure in the utility model.

[0017] Figure 2 It is a schematic diagram of the overall structure of the utility model.

[0018] Description of Figure Numbers:

[0019] 1. Disc; 11. Pouring gate; 2. Pouring cup; 3. Plum blossom test rod pouring riser; 4. Casting shell; 41. Casting cavity. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0024] Example 1

[0025] The utility model provides a technical solution: a stainless steel plum blossom test rod casting shell, such as Figure 1-2 As shown, it includes a disc 1, on which 7 evenly distributed pouring ports 11 are arranged, the top of the disc 1 is connected to the pouring cup 2, the bottom of the pouring ports 11 are respectively connected to the upper ends of the plum blossom test rod pouring risers 3, the lower ends of the plum blossom test rod pouring risers 3 are connected to the casting shell 4, and a casting cavity 41 is arranged inside the casting shell 4.

[0026] The outer side of the casting shell 4 is provided with a surface shell, and the outer side of the surface shell is provided with a reinforcement layer; the surface shell adopts silica sol zircon powder coating, and zircon powder is powder; the coating and powder ratio of the surface shell is 3.0-3.4; the reinforcement layer adopts silica sol mullite powder as coating, and mullite powder is powder; the coating and powder ratio of the reinforcement layer is 2.8-3.6.

[0027] The pouring gate 11 is circular, the interior of the pouring gate 11 is plum blossom-shaped, and the interior of the mold cavity 41 is plum blossom-shaped.

[0028] Example 2

[0029] The stainless steel plum blossom test bar casting shell is realized by the following technical solutions:

[0030] 1. Determine the diameter and thickness of the metal disc master mold according to the size of the crucible well of the 50kg vacuum induction furnace. Press the wax material into the aluminum alloy mold cavity. The wax injection temperature is 55±3℃. Maintain the pressure for a period of time. After cooling and forming, remove the disc wax mold (Disc 1).

[0031] 2. Connect the wax inlet system (pouring cup 2) to one side of the disc wax mold to form a pouring system, and weld the 7 plum blossom test rod wax molds to the other side of the disc wax mold to form a wax mold group.

[0032] 3. Dip the wax model into a ceramic slurry to a thickness of 20-25mm. The surface shell is made using a full silica sol process, with the surface layer made of silica sol zircon powder coating, and the reinforcement layer made of silica sol mullite powder coating, with mullite powder as the powder. The powder-to-liquid ratio for the surface layer is 3.0-3.4, and for the reinforcement layer is 2.8-3.6.

[0033] 4. Heat the hard shell wax mold at 180-220°C to dewax and form a casting cavity 41. Then, bake the shell at 1000-1060°C for 60-90 minutes to ensure that the residual wax is completely burned to obtain a casting shell 4.

[0034] 5. Place the cast shell 4 after being taken out of the furnace into a customized insulation sand box, and then place the sand box into the crucible well. The upper edge of the pouring cup 2 is flush with the crucible well mouth, and the spout mouth, well cover mouth and shell pouring cup are aligned.

[0035] 6. Vacuum remelting uses Fe-Cr-Ni-Co-Mo maraging stainless steel bars as raw materials. The bar diameter is 30-60mm and the surface is clean and rust-free. After the bar is completely melted, it is kept warm and refined for 15-25 minutes. The refining vacuum degree is controlled at 0.5Pa~4Pa.

[0036] 7. The alloy pouring temperature control range is: melting point 50℃~70℃, pouring vacuum is 2Pa~6Pa; after pouring, the furnace is cooled for 2h before breaking the vacuum. After breaking the vacuum, the shell and the casting are separated by manual hammering, and finally the plum blossom test bars are cut off one by one.

[0037] Example 3

[0038] 1. Measure the diameter (325mm) and depth (850mm) of the crucible well of a 50kg vacuum induction furnace. Based on a 45kg charge, determine that the diameter of the metal disc master mold is 260mm and the thickness is 20mm.

[0039] 2. Press the wax material into the aluminum alloy mold cavity with the wax injection temperature at 55°C. Maintain the pressure for a while and remove the disc wax mold (disc 1) after cooling and forming.

[0040] 3. Connect the wax inlet system (pouring cup 2) to one side of the disc wax mold to form a pouring system, and weld 7 plum blossom test rod wax molds to the other side of the disc wax mold to form a wax mold group. Each plum blossom test rod contains 5.2 kg of material.

[0041] 4. Dip the wax model into a 23mm thick ceramic slurry. The surface shell is made using a full silica sol process, with the surface layer made of silica sol zircon powder coating, and the reinforcement layer made of silica sol mullite powder coating, with mullite powder as the powder. The powder-to-liquid ratio for both the surface and reinforcement layers is 3.2.

[0042] 5. The hard shell wax mold is heated at 200°C for dewaxing to form a casting cavity 41. The shell is then fired at 1030°C for 75 minutes to ensure that the residual wax is completely burned to obtain a casting shell 4 (height 420 mm).

[0043] 6. Place the cast shell 4 after being taken out of the furnace into a customized insulation sand box. The temperature of the cast shell 4 out of the furnace is 950℃. Then place the sand box on the stand in the crucible well (stand height 430mm). At this time, the upper edge of the shell pouring cup 2 is flush with the crucible well mouth; close the well cover, place the pouring spout on the well cover, and align the spout mouth, well cover mouth and shell pouring cup 2.

[0044] 7. Use 50mm Fe-Cr-Ni-Co-Mo maraging stainless steel bars as raw materials, shot blast the surface of the bars to ensure cleanliness and rust-free, the total loading amount is 45kg, and after evacuating and heating until the bars are completely melted, keep them warm and refine for 15-25 minutes. The refining vacuum is controlled at 1.5Pa~3Pa.

[0045] 8. The alloy pouring temperature is 1527℃ (60℃ higher than the melting point), and the pouring vacuum is 4Pa. After pouring, the furnace is cooled for 2 hours before breaking the vacuum. After breaking the vacuum, the casting shell 4 and the casting are separated by manual hammering, and finally the plum blossom test bars are cut off one by one.

[0046] 9. According to relevant standards, process samples on the edge of the plum blossom test bar and carry out heat treatment and mechanical property tests.

[0047] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and inventive concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A stainless steel plum blossom test bar casting shell, characterized in that: The invention comprises a disc (1), wherein the disc (1) is provided with a plurality of pouring ports (11), the upper portion of the disc (1) is connected to a pouring cup (2), the lower portions of the pouring ports (11) are respectively connected to the upper ends of plum blossom test rod pouring risers (3), the lower ends of the plum blossom test rod pouring risers (3) are connected to a casting shell (4), and a casting cavity (41) is provided inside the casting shell (4).

2. The stainless steel plum blossom test bar casting shell according to claim 1, characterized in that: The outer side of the casting shell (4) is provided with a surface shell, and the outer side of the surface shell is provided with a reinforcement layer.

3. The stainless steel plum blossom test bar casting shell according to claim 1, characterized in that: The pouring port (11) is circular, the interior of the pouring port (11) is plum blossom-shaped, and the interior of the casting cavity (41) is plum blossom-shaped.

4. The stainless steel plum blossom test bar casting shell according to claim 2, characterized in that: The surface shell is made of silica sol zircon powder paint, and the zircon powder is powder material; the paint and material-powder ratio of the surface shell is 3.0-3.

4.

5. The stainless steel plum blossom test bar casting shell according to claim 2, characterized in that: The reinforcement layer uses silica sol mullite powder as coating material and mullite powder as powder material; the coating material to powder material ratio of the reinforcement layer is 2.8-3.

6.

6. The stainless steel plum blossom test bar casting shell according to claim 1, characterized in that: The disc (1) is provided with seven pouring ports (11) symmetrically distributed.

Images