Multifunctional flange plate for mounting, sealing and heat preservation of riser tube for anti-gravity casting

Abstract

The invention discloses a multifunctional flange plate for mounting, sealing and insulating a riser tube for anti-gravity casting. The invention relates to a multifunctional flange plate for mounting, sealing and heat preservation of a riser tube for anti-gravity casting. The neck sleeve consists of an end part and a neck part, the end part is positioned at the upper end of the neck part to form an annular interface structure; an annular groove for mounting a graphite sealing ring is formed in the upper surface of the end part; and the neck part is divided into a straight tube section, an inclined surface section and a step section from top to bottom. The sealing problem of the riser tube channel between the smelting chamber and the mold chamber in anti-gravity casting can be solved, it is ensured that effective pressure difference can be established between the smelting chamber and the mold chamber during mold filling, and smooth mold filling of molten metal is ensured. Accurate limiting during mounting of the riser tube is achieved, dislocation of an upper port of the riser tube and an inlet of a mold cavity is prevented, the mold is prevented from being scoured and corroded, turbulent flow of metal liquid flow is avoided, the service life of the mold is prolonged, and casting metallurgical quality is improved. The heat preservation problem of the riser tube in the process from preheating completion to mold filling completion is solved, the temperature loss speed is reduced, the liquidity of molten metal is guaranteed, and the casting forming quality and performance are improved.

Description

Technical Field

[0001] The invention relates to a sealing and heat-insulating multifunctional flange for mounting a liquid riser pipe for counter-gravity casting. Background Art

[0002] As a unique casting method, counter-gravity casting uses external pressure to drive the molten metal to fill the mold from bottom to top in the riser against the direction of gravity and solidify under controllable pressure. It is widely used in many fields with high requirements for casting quality, such as aerospace, automobile manufacturing, etc. Usually, the counter-gravity casting device is mainly composed of a melting chamber, a mold chamber and a middle partition, such as Figure 1 As shown. In this casting process, after the smelting chamber completes the metal smelting, the molten metal needs to be guided to the mold chamber through the riser pipe to achieve filling. In this process, there are several key issues that need to be solved. The first is the sealing problem. During the filling stage, the smelting chamber and the mold chamber must be completely sealed, especially the riser pipe channel. Once gas cross-talk occurs, the necessary pressure difference ΔP cannot be established between the two chambers; and the pressure difference is the key driving force for the molten metal to fill the mold. If the pressure difference cannot be established, the molten metal cannot be filled as expected, which will directly lead to the failure of the casting process and seriously affect production efficiency and casting output. At present, although the industry is aware of the importance of sealing the riser pipe channel, there is still a lack of efficient and reliable sealing solutions, which makes it difficult to guarantee the sealing effect, which has become a major bottleneck restricting the development of anti-gravity casting technology.

[0003] The second is the problem of installation limit. When filling the mold, the upper port of the riser tube and the inlet of the mold cavity need to be accurately matched and connected; however, in the actual installation of the riser tube and the mold, if there is a lack of effective limit measures, the upper port of the riser tube and the inlet of the mold cavity are very likely to be misaligned. This misalignment will lead to a series of adverse consequences. On the one hand, the molten high-temperature metal liquid will erode the mold, greatly shorten the service life of the mold, and increase production costs; on the other hand, it may also cause the front end of the filling metal liquid flow to become unstable and turbulent, which will lead to quality problems such as air entrainment and slag inclusion, seriously reducing the metallurgical quality of the casting, and cannot meet the stringent requirements of the high-end field for casting quality.

[0004] The next issue is the thermal insulation of the riser. The fluidity of the molten metal during rising and filling is closely related to the temperature. In most cases, the riser needs to be preheated to a specific temperature depending on the smelting alloy. However, the current dilemma is that the temperature of the riser dissipates quickly from the time preheating is completed to the time filling is completed. The rapid drop in temperature will cause the fluidity of the molten metal to deteriorate, resulting in incomplete filling, cold shut of the casting and other defects, which greatly affects the molding quality and performance of the casting. Although some studies have focused on the thermal insulation of the riser, a mature and effective thermal insulation technology solution has not yet been formed to meet actual production needs. Summary of the invention

[0005] The present invention is to solve a series of problems such as sealing, limiting and heat preservation of the riser pipe in the counter-gravity casting process, and provides a multifunctional flange for sealing and heat preservation of the riser pipe for counter-gravity casting.

[0006] The invention discloses a sealing and heat-insulating multifunctional flange for installing a liquid riser for anti-gravity casting, which is composed of an end portion and a neck portion; the end portion is located at the upper end of the neck portion to form an annular interface structure, and an annular groove is processed on the upper surface of the end portion to install a graphite sealing ring; the neck portion is divided into a straight section, an inclined section and a terrace section from top to bottom; the angle between the inclined surface of the inclined section and the vertical direction is α; the outer diameter of the straight section is D 1 , the inner diameter of the straight section is D 2 , the inner diameter of the bottom end of the slope section is D 4 , the inner diameter of the stage is D 5 ; said D 4 >D 5 .

[0007] Advantages of the present invention:

[0008] The present invention can solve the sealing problem of the riser tube channel between the smelting chamber and the mold chamber in anti-gravity casting, ensure that an effective pressure difference can be established between the two chambers during mold filling, and ensure smooth filling of the mold with molten metal. It can achieve precise positioning of the riser tube during installation, prevent the upper port of the riser tube from being misaligned with the mold cavity entrance, avoid erosion of the mold and turbulence of the molten metal flow, and improve the mold life and metallurgical quality of the casting. It can improve the insulation problem of the riser tube from the completion of preheating to the completion of filling, slow down the temperature loss rate, ensure the fluidity of the molten metal, and improve the molding quality and performance of the casting; and it can install riser tubes of different diameters, so that one plate can be used for multiple purposes, which greatly reduces the production cost of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram of the structure of a sealing and heat-insulating multifunctional flange installed on a liquid riser pipe for anti-gravity casting;

[0010] Figure 2 It is a structural schematic diagram of the liquid riser described in Example 1;

[0011] Figure 3 This is the overall schematic diagram of the installation of the mold, riser and flange;

[0012] Figure 4 It is a structural schematic diagram of the liquid riser described in Example 2;

[0013] Figure 5 Schematic diagram of the placement of the middle partition and sealing material on the device. DETAILED DESCRIPTION

[0014] Specific implementation method 1: Combined with the accompanying drawings, this implementation method is described. In this implementation method, a sealing and heat-insulating multifunctional flange for installing a riser pipe for anti-gravity casting is composed of an end 1 and a neck 2; the end 1 is located at the upper end of the neck 2 to form an annular interface structure, and the upper surface of the end 1 is processed with an annular groove 3 for installing a graphite sealing ring 10; the neck 2 is divided into a straight section 21, a slope section 22 and a platform section 23 from top to bottom; the angle between the slope of the slope section 22 and the vertical direction is α; the outer diameter of the straight section 21 is D 1 , the inner diameter of the straight section 21 is D 2 The inner diameter of the bottom end of the inclined surface section 22 is D 4 , the inner diameter of stage 23 is D 5 ; said D 4 >D 5 .

[0015] This embodiment has a simple design and is easy to process and manufacture. At the same time, the high positioning accuracy prevents the molten high-temperature metal from eroding the mold and improving the life of the mold. It also avoids the front end of the metal liquid flow entering the cavity entrance from becoming unstable and causing turbulence, thereby improving the metallurgical quality of the casting.

[0016] In this embodiment, refractory insulation cotton is filled between the riser tube and the flange straight tube to ensure that the melt in the riser tube solidifies last, which is beneficial to continuously apply pressure to the metal melt in the cavity through the riser tube until the metal melt in the cavity is completely solidified, thereby improving the shrinkage compensation effect of the casting, reducing the number of shrinkage porosity and shrinkage holes, and improving the quality of the casting.

[0017] The flange can be used for installation and sealing of riser pipes with different diameters, achieving multiple uses and significantly reducing casting costs.

[0018] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that: the end 1 is provided with a bolt connection hole 12 aligned with the corresponding hole position of the mold 5, and the end 1 is fastened to the mold 5 by bolts; the lower end of the riser 6 is inserted into the molten metal in the crucible 7, and is used to introduce the molten metal 8 in the crucible 7 into the cavity 9 under the action of counter-gravity; the inclined section 22 limits the riser 6; the part where the riser 6 is connected to the flange 4 is coated with refractory insulation cotton 11; the upper end of the riser 6 and the entrance of the cavity 9 are sealed by a graphite sealing ring 10. Others are the same as specific embodiment 1.

[0019] The graphite sealing ring in this embodiment can be replaced by asbestos rope. The above material has good sealing performance, can effectively fill the gap between the riser and the mold cavity entrance, prevent gas leakage, ensure that the melting chamber and the mold chamber are sealed during the filling stage, thereby ensuring that the necessary pressure difference ΔP can be established between the two chambers to push the metal liquid to fill the mold, and avoid casting process failure caused by cross-gas.

[0020] This embodiment adopts bolt fixing. This connection method further ensures the relative position accuracy between the riser tube and the mold, maintains the correct connection between the upper port of the riser tube and the inlet of the mold cavity during filling, prevents problems such as erosion of the mold by the molten metal due to misalignment and instability of the front end of the filling molten metal flow, thereby improving the metallurgical quality of the casting and extending the service life of the mold.

[0021] In this embodiment, the portion where the riser pipe is connected to the flange is coated with refractory heat-insulating cotton. The refractory heat-insulating cotton has good heat-insulating performance, which can effectively reduce the heat loss of the riser pipe from the completion of preheating to the completion of filling, slow down the temperature drop of the riser pipe, and enable the molten metal to maintain good fluidity, thereby avoiding defects such as poor fluidity of the molten metal, incomplete filling, and cold shut of the casting caused by rapid temperature drop, thereby improving the molding quality and performance of the casting.

[0022] Specific implementation method 3: This implementation method is different from the specific implementation method 1 in that the value of α is 10 to 30°. The rest is the same as the specific implementation method 1.

[0023] Specific embodiment 4: This embodiment is different from the specific embodiment 2 in that: the riser pipe 6 is a segmented structure with a wide top and a narrow bottom, and the outer diameter of the upper segment is d 2 , the inner diameter of the upper section is d 1 , the outer diameter of the lower section is d 3 The rest is the same as the second specific implementation method.

[0024] Specific implementation method 5: This implementation method is different from the specific implementation method 4 in that the outer diameter d of the upper section 2 Control in D 4 ~D 5 The rest is the same as the fourth embodiment.

[0025] Specific implementation method 6: This implementation method is different from the specific implementation method 4 in that the outer diameter d of the upper section 2 Control The rest is the same as the fourth specific implementation method.

[0026] The inclined surface structure plays a good guiding role, facilitating the installation of the riser pipe, and can also prevent the riser pipe from being damaged by friction between the outer surface of the riser pipe and the inner wall of the flange, especially for the relatively fragile ceramic riser pipe. 2 When within the specified range, the bottom slope of the flange can completely limit the riser tube, ensuring that the upper port of the riser tube is accurately matched and connected to the inlet of the mold cavity to avoid misalignment.

[0027] Specific embodiment 7: This embodiment is different from the specific embodiment 2 in that: the liquid riser 6 is a three-section structure with narrow ends and a wide middle, and the outer diameter of the narrow section is b 3 , the inner diameter of the narrow section is b 1 , the outer diameter of the middle section is b 2 The rest is the same as the second specific implementation method.

[0028] Specific implementation eight: This implementation differs from specific implementation seven in that the outer diameter b of the middle section 3 Control in D 4 ~D 5 The rest is the same as the seventh embodiment.

[0029] Specific embodiment 9: This embodiment is different from specific embodiment 7 in that the outer diameter b of the middle section 3 Control The rest is the same as the seventh specific implementation method.

[0030] Specific embodiment 10: This embodiment is different from the specific embodiment 2 in that: after the mold 5, the riser 6 and the flange 4 are installed, they are transferred into the mold room as a whole; then the upper and lower tanks of the device start to evacuate synchronously, and after the vacuum requirement is met, the riser 6 starts to preheat, and the lower tank starts to melt the material at the same time; after the material is melted and the riser is preheated, the mold 5 is lowered as a whole, and at this time the straight tube of the flange 4 will pass through the middle partition 13 on the device, and the inner diameter of the middle partition 13 is D 3， Guarantee D 1 <D 3 At the same time, the lower surface of the upper end of the flange 4 completely compresses the graphite seal ring 10 placed on the middle partition 13, and the upper and lower tanks are completely isolated. Then, the lower tank is inlet or the upper tank is exhausted to complete the liquid lifting and filling. The rest is the same as the second specific embodiment.

[0031] The beneficial effects of the present invention are verified by the following examples:

[0032] Embodiment 1: A sealing and heat-insulating multifunctional flange for installing a liquid riser for anti-gravity casting is composed of an end 1 and a neck 2; the end 1 is located at the upper end of the neck 2 to form an annular interface structure, and an annular groove 3 is processed on the upper surface of the end 1 to install a graphite sealing ring 10; the neck 2 is divided into a straight section 21, a slope section 22 and a platform section 23 from top to bottom; the angle between the slope of the slope section 22 and the vertical direction is α; the outer diameter of the straight section 21 is D 1 , the inner diameter of the straight section 21 is D 2 The inner diameter of the bottom end of the inclined surface section 22 is D 4 , the inner diameter of stage 23 is D 5 ; said D 4 >D 5 ;

[0033] The end portion 1 is provided with a bolt connection hole 12 which is aligned with the corresponding hole position of the mold 5, and the end portion 1 is fastened to the mold 5 by bolts; the lower end of the riser tube 6 is inserted into the molten metal in the crucible 7, and is used to introduce the molten metal in the crucible 7 into the mold cavity 9 under the action of counter-gravity; the inclined surface section 22 limits the riser tube 6; the portion where the riser tube 6 is connected to the flange 4 is coated with refractory insulation cotton 11; the upper end of the riser tube 6 is sealed and connected to the entrance of the mold cavity 9 by a graphite sealing ring 10;

[0034] The value of α is 10 to 30°; the riser pipe 6 is a segmented structure with a wide top and a narrow bottom, and the outer diameter of the upper segment is d 2 , the inner diameter of the upper section is d 1 , the outer diameter of the lower section is d 3 The outer diameter d of the upper section 2 Control in D 4 ~D 5 The inclined surface facilitates the installation of the riser tube (guiding function) and can also prevent the riser tube (especially the ceramic riser tube) from being damaged by friction between the outer surface of the riser tube and the inner wall of the flange. In addition, the outer diameter d2 of the riser tube is kept at When the riser is installed, the bottom slope of the flange can completely limit the position of the riser pipe, and then the upper mold and the upper end of the flange (with a graphite sealing ring placed in the groove) are fastened by bolts, which can ensure the best sealing and matching connection between the riser pipe opening and the mold cavity entrance. The upper end of the riser pipe is connected to the mold cavity entrance through a graphite sealing ring. See the overall installation diagram. Figure 4 This can prevent the molten high-temperature metal from eroding the mold and from causing turbulence due to the instability of the front end of the metal liquid flow entering the cavity entrance, thereby improving the metallurgical quality of the casting.

[0035] In addition, since the fluidity and temperature of the molten metal during lifting and filling are closely related, the riser tube needs to be preheated in most cases (the preheating temperature is determined according to the smelting alloy, and the maximum temperature shall not exceed 900°C to prevent the stainless steel flange from softening). However, if the riser tube is not well insulated after preheating, the temperature of the riser tube will drop quickly. Fill the riser tube with refractory insulation cotton between the flange and the riser tube (above the inclined surface of the flange. If there is no processed inclined surface, only a right-angle flange, the precise positioning between the installation of the riser tube and the placement of the refractory insulation cotton cannot be guaranteed). This can slow down the temperature drop rate of the riser tube when it is immersed in the melt in the crucible after preheating, reduce the temperature difference with the melt, and avoid the cracking of some riser tubes with poor thermal shock resistance when immersed in the melt, causing filling failure. At the same time, good insulation of the riser tube during filling can ensure that the melt in the riser tube solidifies last, which can maximize the advantages of the anti-gravity casting process, that is, the metal melt in the cavity can be continuously pressured through the riser tube until the metal melt in the cavity is completely solidified, thereby improving the shrinkage compensation effect of the casting, reducing the number of shrinkage cavities and shrinkage holes, and improving the quality of the casting.

[0036] Embodiment 2: This embodiment is different from Embodiment 1 in that: when the inner diameter of the riser pipe is small and the wall thickness is small, the riser pipe 6 is a three-section structure with narrow ends and a wide middle, and the outer diameter of the narrow section is b 3 , the inner diameter of the narrow section is b 1 , the outer diameter of the middle section is b 3 The outer diameter b of the intermediate section 3 Control in D 4 ~D 5 The outer diameter b of the intermediate section 3 Control That is, the flange plate takes into account the installation and use requirements of various liquid riser pipe diameters, achieves a multi-purpose effect, and greatly reduces the production cost of castings. Other aspects are the same as those of the first embodiment.

[0037] After the mold 5, the riser 6 and the flange 4 are installed, they are transferred into the mold room as a whole; then the upper and lower tanks of the device start to evacuate synchronously, and after the vacuum requirement is met, the riser 6 starts to preheat, and the lower tank starts to melt the material at the same time; after the material is melted and the riser is preheated, the mold 5 is lowered as a whole, and at this time the straight tube of the flange 4 will pass through the middle partition 13 on the device, and the inner diameter of the middle partition 13 is D 3， Guarantee D 1 <D 3 At the same time, the lower surface of the upper end of the flange 4 completely compresses the graphite sealing ring 10 placed on the middle partition 13. At this time, the upper and lower tanks are completely isolated, and then the lower tank is inlet or the upper tank is exhausted to complete the liquid lifting and filling.

Claims

1. A multifunctional flange for sealing and heat preservation of a liquid riser for anti-gravity casting, characterized in that The flange plate is composed of an end portion (1) and a neck portion (2); the end portion (1) is located at the upper end of the neck portion (2) to form an annular interface structure, and an annular groove (3) is processed on the upper surface of the end portion (1) for installing a graphite sealing ring (10); the neck portion (2) is divided into a straight section (21), a slope section (22) and a step section (23) from top to bottom; the angle between the slope of the slope section (22) and the vertical direction is α; the outer diameter of the straight section (21) is D1, the inner diameter of the straight section (21) is D2, the inner diameter of the bottom end of the slope section (22) is D4, and the inner diameter of the step section (23) is D5; D4>D5.

2. According to claim 1, a sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting, characterized in that The end portion (1) is provided with a bolt connection hole (12) which is aligned with a corresponding hole position of the mold (5), and the end portion (1) is fastened to the mold (5) by bolts; the lower end of the riser tube (6) is inserted into the molten metal (8) in the crucible (7) to guide the molten metal in the crucible (7) into the mold cavity (9) under the action of counter-gravity; the inclined surface section (22) limits the position of the riser tube (6); the portion where the riser tube (6) is connected to the flange (4) is coated with refractory heat-insulating cotton (11); the upper end of the riser tube (6) and the entrance of the mold cavity (9) are sealed by a graphite sealing ring (10).

3. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 1, characterized in that The value of α is 10 to 30°.

4. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 2, characterized in that The liquid riser (6) is a segmented structure that is wider at the top and narrower at the bottom. The outer diameter of the upper segment is d2, the inner diameter of the upper segment is d1, and the outer diameter of the lower segment is d3.

5. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 4, characterized in that The outer diameter d2 of the upper section is controlled between D4 and D5.

6. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 4, characterized in that The outer diameter d2 of the upper section is controlled at 7. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 2, characterized in that The liquid riser (6) is a three-section structure with narrow ends and a wide middle. The outer diameter of the narrow section is b3, the inner diameter of the narrow section is b1, and the outer diameter of the middle section is b2.

8. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 7, characterized in that The outer diameter b3 of the middle section is controlled between D4 and D5.

9. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 7, characterized in that The outer diameter b3 of the middle section is controlled at 10. The sealing and heat-insulating multifunctional flange for installing a liquid riser pipe for anti-gravity casting according to claim 2, characterized in that After the mold (5), the liquid riser (6) and the flange (4) are installed, they are transferred into the mold room as a whole; then the upper and lower tanks of the device start to evacuate the vacuum synchronously, and after the vacuum requirement is met, the liquid riser (6) starts to preheat, and at the same time, the lower tank starts to melt the material; after the material is melted and the liquid riser is preheated, the mold (5) is lowered as a whole, and at this time, the straight tube of the flange (4) will pass through the middle partition (13) on the device, and the inner diameter of the middle partition (13) is D 3， Ensure that D1 is less than D3; at the same time, the lower surface of the upper end of the flange (4) completely compresses the graphite sealing ring (10) placed on the middle partition (13). At this time, the upper and lower tanks are completely isolated, and then the lower tank is inlet or the upper tank is exhausted to complete the liquid lifting and filling.

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