Bottom pouring type magnesium alloy casting mold with extruding and throttling functions and using method of bottom pouring type magnesium alloy casting mold

Abstract

The invention provides a bottom pouring type magnesium alloy casting mold with an extrusion throttling function. A supporting plate is arranged at the bottom of an upper mold, a throttling valve is arranged in the supporting plate, a spring is arranged between the throttling valve and the supporting plate, an extrusion sliding block is arranged on the upper portion of the upper mold, a flow guide channel is formed in the middle of a lower mold, and the flow guide channel and the throttling valve are oppositely arranged; six forming holes are distributed in the outer side of the flow guide channel in the radial direction, and the bottoms of the forming holes communicate with the bottom of the flow guide channel through a bottom injection channel; in the casting process, under the action of extrusion force, the liquidity of magnesium alloy liquid is greatly improved, the mold filling capacity of magnesium alloy is enhanced, and an obtained sample is free of oxidation and cold shut phenomena; the magnesium alloy liquid is subjected to extrusion force and shear force at the throttling holes, so that a magnesium alloy sample with fine grains can be obtained, and the casting cost and the rejection rate are greatly reduced; and the whole casting process can be completed by only 1-2 persons, so that the production efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium alloy casting, in particular to a bottom-pouring casting magnesium alloy mold with an extrusion throttling function and a use method thereof. Background Art

[0002] Molten magnesium alloy is easy to oxidize and burn due to its high temperature. When using the traditional casting method, the magnesium alloy liquid and the cast sample need gas protection to avoid air oxidation due to the high temperature. The amount of protective gas is large, and the obtained magnesium alloy sample has coarse grains and low mechanical properties. In addition, it requires the assistance of multiple people to complete the casting, which is costly and has many defects in the cast samples.

[0003] Therefore, there is an urgent need for a bottom-casting magnesium alloy mold with an extrusion throttling function and a method of use that can solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a bottom-casting magnesium alloy mold with an extrusion throttling function and a method of using the mold to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a bottom-injection casting mold for magnesium alloys with an extrusion throttling function, comprising an upper mold, a lower mold installed at the bottom of the upper mold, a support plate provided at the bottom of the upper mold, a throttle valve provided in the support plate, a spring provided between the throttle valve and the support plate, an extrusion slider provided at the upper part of the upper mold, a guide channel provided at the middle part of the lower mold, the guide channel and the throttle valve are arranged opposite to each other, forming holes are distributed on the outside of the guide channel, and the bottom of the forming holes is connected with the bottom of the guide channel through a bottom injection channel.

[0007] Preferably, a positioning groove is provided on the top of the lower mold, and the upper mold is detachably limited in the positioning groove.

[0008] Preferably, a step is provided on the lower side wall of the upper mold, and the support plate is limited to the step.

[0009] Preferably, a throttle valve guide hole is provided in the middle of the support plate, the throttle valve is installed in the throttle valve guide hole, an annular throttle groove is provided below the throttle valve guide hole, a spring groove is provided below the annular throttle groove, and the spring is installed in the spring groove.

[0010] Preferably, the longitudinal section of the throttle valve is a T-shaped structure, with a throttling hole provided on its upper portion and a guide hole connected to the throttling hole provided on its lower portion. The guide hole and the guide channel are arranged relative to each other, and when the spring is compressed, the annular throttling groove and the throttling hole are positioned relative to each other.

[0011] Preferably, an annular flow suppression groove is provided on the side of the extrusion slide block.

[0012] Preferably, an overflow hole is provided at the upper portion of the lower mold, and the overflow hole is communicated with the molding hole.

[0013] The present invention also provides a method for using a bottom-injection casting magnesium alloy mold with an extrusion throttling function, which comprises placing an upper mold filled with magnesium alloy liquid on a preheated lower mold, and then placing a preheated extrusion slider on top of the magnesium alloy liquid in the upper mold, applying an extrusion force, and extruding the magnesium alloy liquid through the extrusion slider. The extrusion force is transmitted to the throttle valve on the support plate, so that the throttle valve drives the spring in the spring groove to slide downward, so that the magnesium alloy liquid enters the annular throttling groove of the support plate, and then flows into the throttle hole and the guide hole of the throttle valve in turn, and then flows into the guide channel of the lower mold through the guide hole. Under the action of continuous extrusion pressure, the magnesium alloy liquid flows from the bottom injection channel into the forming hole of the lower mold through the guide channel, thereby completing the magnesium alloy forming.

[0014] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0015] The present invention provides a bottom-injection casting magnesium alloy mold with an extrusion throttling function. The bottom of the upper mold is provided with a support plate, a throttle valve is provided in the support plate, a spring is provided between the throttle valve and the support plate, an extrusion slider is provided at the upper part of the upper mold, a guide channel is provided in the middle part of the lower mold, the guide channel and the throttle valve are arranged opposite to each other, six forming holes are distributed radially on the outer side of the guide channel, and the bottom of the forming hole is connected with the bottom of the guide channel through a bottom injection channel; during the casting process, the magnesium alloy liquid is greatly improved in fluidity under the action of the extrusion force, and the filling capacity of the magnesium alloy is enhanced, and the obtained sample has no oxidation and cold shut phenomenon; the magnesium alloy liquid is not only subjected to the extrusion force, but also subjected to the shear force at the throttle hole, so that a magnesium alloy sample with fine grains can be obtained, and the present invention greatly reduces the casting cost and the scrap rate; only 1-2 people are needed to complete the entire casting process, and the production efficiency is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative labor.

[0017] Figure 1 A schematic diagram of the structure of a bottom-pouring casting mold for magnesium alloys with an extrusion throttling function provided by the present invention;

[0018] Figure 2 A schematic diagram of the structure of the upper die portion of a bottom-injection casting die for magnesium alloys with an extrusion throttling function provided by the present invention;

[0019] Figure 3 A schematic diagram of the structure of a support plate portion in a bottom-injection casting mold for magnesium alloys with an extrusion throttling function provided by the present invention;

[0020] Figure 4 A schematic diagram of the structure of a throttle valve in a bottom-injection casting mold for magnesium alloys with an extrusion throttling function provided by the present invention;

[0021] Figure 5 A schematic diagram of the structure of an extrusion slider in a bottom-injection casting mold for magnesium alloys with an extrusion throttling function provided by the present invention;

[0022] Figure 6 A schematic diagram of the structure of the lower die portion of a bottom-injection casting magnesium alloy die with an extrusion throttling function provided by the present invention;

[0023] Figure 7 This is the metallographic structure diagram of the 1.0%Ca-1.0%Sr sample;

[0024] Figure 8 This is the metallographic structure diagram of the 1.0%Ca-2.0%Sr sample. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a bottom-pouring casting magnesium alloy mold with an extrusion throttling function and a use method thereof, so as to solve the problems existing in the prior art.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Embodiment 1:

[0029] This embodiment provides a bottom-injection casting magnesium alloy mold with an extrusion throttling function, such as Figure 1-6 As shown, it includes an upper mold 1, a lower mold 2 is installed at the bottom of the upper mold 1, a support plate 3 is provided at the bottom of the upper mold 1, a throttle valve 4 is provided in the support plate 3, a spring 5 is provided between the throttle valve 4 and the support plate 3, an extrusion slider 6 is provided at the upper part of the upper mold 1, a guide channel 7 is provided in the middle part of the lower mold 2, the guide channel 7 is arranged opposite to the throttle valve 4, and forming holes 8 are distributed on the outside of the guide channel 7, and the bottom of the forming hole 8 is connected with the bottom of the guide channel 7 through a bottom injection channel 9.

[0030] As an implementation mode, a positioning groove 10 is provided on the top of the lower mold 2, and the upper mold 1 is detachably restrained in the positioning groove 10, thereby achieving a high-precision connection between the two.

[0031] As an implementation mode, a step 11 is provided on the lower side wall of the upper mold 1, and the support plate 3 is limited at the step 11, so as to achieve the assembly of the two.

[0032] As an implementation mode, a throttle valve guide hole 12 is provided in the middle of the support plate 3, the throttle valve 4 is installed in the throttle valve guide hole 12, an annular throttle groove 13 is provided below the throttle valve guide hole 12, a spring groove 14 is provided below the annular throttle groove 13, and the spring 5 is installed in the spring groove 14.

[0033] As an embodiment, the longitudinal section of the throttle valve 4 is a T-shaped structure, a throttling hole 15 is provided at the upper part thereof, and a guide hole 16 connected to the throttling hole 15 is provided at the lower part thereof. The guide hole 16 and the guide channel 7 are arranged relative to each other. When the spring 5 is compressed, the annular throttling groove 13 and the throttling hole 15 are relative to each other.

[0034] As an implementation mode, an annular flow suppression groove 17 is provided on the side of the extrusion slide block 6, and the annular flow suppression groove can prevent the magnesium alloy liquid from flowing out when the magnesium alloy liquid is extruded at work.

[0035] As an implementation mode, an overflow hole 18 is provided at the upper portion of the lower mold 2 , and the overflow hole 18 is connected to the molding hole 8 .

[0036] The method for using the bottom-injection casting magnesium alloy mold with extrusion throttling function provided in the above embodiment is as follows: an upper mold 1 filled with magnesium alloy liquid is placed on a preheated lower mold 2, and then a preheated extrusion slider 6 is placed on the top of the magnesium alloy liquid in the upper mold 1, and an extrusion force is applied to extrude the magnesium alloy liquid through the extrusion slider 6. The extrusion force is transmitted to the throttle valve 4 on the support plate 3, so that the throttle valve 4 drives the spring 5 in the spring groove 14 to slide downward, so that the magnesium alloy liquid enters the annular throttling groove 13 of the support plate 3, and then flows into the throttle hole 15 and the guide hole 16 of the throttle valve 4 in turn, and then flows into the guide channel 7 of the lower mold 2 through the guide hole 16. Under the action of continuous extrusion pressure, the magnesium alloy liquid flows from the bottom injection channel 9 through the guide channel 7 into the forming hole 8 of the lower mold, completing the magnesium alloy forming.

[0037] The applicant used the above mold and method to carry out an experiment to prepare Mg-2Si-Ca-Sr magnesium alloy samples. The raw materials required for this experiment were pure magnesium ingots, pure aluminum ingots (purity of 99.9%), Mg-30% Si, Mg-20% Ca and Mg-20% Sr intermediate alloys. The main experimental steps are as follows:

[0038] (1) After weighing the pure magnesium ingot, pure aluminum ingot and various master alloys according to the calculated composition, put them into an oven and preheat them to 200°C;

[0039] (2) After preheating the upper mold 1 to dark red in a crucible melting furnace, put in a pure magnesium ingot and introduce 1.5% FS6 (sulfur hexafluoride) + CO2 as a protective gas;

[0040] (3) After the magnesium ingot is melted, add the pure aluminum ingot and heat it to 750°C; after both are completely melted, add the preheated Mg-30% Si master alloy, stir for 3-5 minutes after all are melted, and keep warm for 15 minutes; then add the Mg-20% Ca and Mg-20% Sr master alloys respectively, and keep warm at 750°C for 15 minutes;

[0041] After argon refining, the surface oxidation residue is removed, and then the upper mold 1 containing the magnesium alloy liquid is taken out from the melting furnace and placed in the preheated lower mold 2. When the temperature of the magnesium alloy liquid drops to 720°C, the surface oxidation residue of the liquid is removed, and then the preheated extrusion slider 6 is placed on the magnesium alloy liquid, and a mechanical force is applied to the extrusion slider 6 to complete the magnesium alloy forming, thereby obtaining the desired sample, such as Figure 7 and 8 The metallographic structure of the sample shown under a 500x optical microscope shows that the sample has no oxidation, no cold shut, and has small grains, and the sample has excellent formability.

[0042] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A bottom-injection casting mold for magnesium alloy with extrusion throttling function, characterized in that: It includes an upper mold, a lower mold is installed at the bottom of the upper mold, a support plate is provided at the bottom of the upper mold, a throttle valve is provided in the support plate, a spring is provided between the throttle valve and the support plate, an extrusion slider is provided at the upper part of the upper mold, a guide channel is provided in the middle part of the lower mold, the guide channel is arranged opposite to the throttle valve, forming holes are distributed on the outside of the guide channel, and the bottom of the forming holes is connected with the bottom of the guide channel through a bottom injection channel.

2. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 1 is characterized in that: A positioning groove is provided on the top of the lower mold, and the upper mold is detachably limited in the positioning groove.

3. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 1 is characterized in that: The lower side wall of the upper mold is provided with a step, and the support plate is limited to the step.

4. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 1 is characterized in that: A throttle valve guide hole is provided in the middle of the support plate, the throttle valve is installed in the throttle valve guide hole, an annular throttle groove is provided below the throttle valve guide hole, a spring groove is provided below the annular throttle groove, and the spring is installed in the spring groove.

5. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 4 is characterized in that: The longitudinal section of the throttle valve is a T-shaped structure, with a throttling hole provided on its upper portion and a guide hole connected to the throttling hole provided on its lower portion. The guide hole and the guide channel are arranged relative to each other. When the spring is compressed, the annular throttling groove and the throttling hole are relative to each other.

6. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 1 is characterized in that: An annular flow suppression groove is provided on the side of the extrusion sliding block.

7. The bottom pouring casting magnesium alloy mold with extrusion throttling function according to claim 1 is characterized in that: An overflow hole is provided on the upper portion of the lower mold, and the overflow hole is communicated with the molding hole.

8. A method for using a bottom-injection casting magnesium alloy mold with an extrusion throttling function, characterized in that: The upper die filled with magnesium alloy liquid is placed on the preheated lower die, and the preheated extrusion slider is placed on the top of the magnesium alloy liquid in the upper die, and an extrusion force is applied to extrude the magnesium alloy liquid through the extrusion slider. The extrusion force is transmitted to the throttle valve on the support plate, so that the throttle valve drives the spring in the spring groove to slide downward, so that the magnesium alloy liquid enters the annular throttle groove of the support plate, and then flows into the throttle hole and guide hole of the throttle valve in turn. The magnesium alloy liquid flows into the guide channel of the lower die through the guide hole. Under the continuous extrusion pressure, The magnesium alloy is injected from the bottom into the forming hole of the lower die through the guide channel to complete the magnesium alloy forming.

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