Low-pressure metal mold tensile test bar forming die and forming method thereof

Abstract

The application belongs to the technical field of aluminum alloy manufacturing, and discloses a low-pressure metal mold tensile test bar forming die and a forming method thereof. The die comprises a left mold, a right mold and a bottom mold. The inside of the left mold and the right mold after clamping by a clamping assembly has a test bar cavity and a pouring channel. The pouring channel comprises a cross gate, a straight gate, a first feeding gate, a feeding riser, a second feeding gate and an inner gate. The straight gate and the feeding riser are arranged at the upper part of the cross gate respectively. The inner gate and the test bar cavity are arranged above the cross gate respectively. The straight gate, the feeding riser and the cross gate are in communication. The straight gate is in communication with the feeding riser through the inner gate. The feeding riser is in communication with the test bar cavity through the first feeding gate and the second feeding gate. The bottom mold is provided with a pouring opening. The cross gate is in communication with the pouring opening. Through the die and the forming method, the forming conditions of the test bar and the low-pressure metal mold casting can be consistent, so that whether the casting is qualified can be more objectively evaluated.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy manufacturing, and particularly relates to a low-pressure permanent mold tensile test bar forming die and a forming method thereof. Background Art

[0002] At present, the mechanical properties of low-pressure permanent mold castings are mainly evaluated by tensile tests of test bars. The test bars are mainly divided into separately cast test bars (gravity permanent mold test bars, gravity sand mold test bars), attached test bars (test bars processed from test blocks attached to castings) and body test bars (test bars processed from test blocks cut from casting bodies). Since separately cast test bars and castings have great differences in filling mode, filling pressure and feeding pressure, it cannot be guaranteed that they can accurately reflect the actual properties of castings. Qualified castings themselves may be judged unqualified due to unqualified test bars, resulting in waste. Although attached test bars and body test bars can objectively evaluate the properties of casting bodies, attached test bars require complex processing, and body test bars will damage the castings, so the cost of these two types of test bars is relatively high. Summary of the Invention

[0003] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. Therefore, the present invention provides a low-pressure permanent mold tensile test bar forming die and a forming method thereof. The low-pressure permanent mold tensile test bar forming die provided by the present invention can form a test bar in a low-pressure casting manner, and the forming conditions of the test bar are consistent with those of the low-pressure permanent mold casting, which can more accurately reflect the actual properties of the casting.

[0004] According to a first aspect of the present invention, there is provided a low-pressure permanent mold tensile test bar forming die, comprising a left die, a right die and a bottom die. After the left die and the right die are clamped by a clamping assembly, a test bar cavity and a pouring channel are formed inside. The pouring channel comprises a horizontal runner, a sprue, a first feeding runner, a feeding riser, a second feeding runner and an ingate. The sprue and the feeding riser are respectively arranged on an upper portion of the horizontal runner, and the sprue and the feeding riser are respectively communicated with the horizontal runner. The ingate and the test bar cavity are respectively arranged above the horizontal runner, a first end of the ingate is communicated with the sprue, a second end of the ingate is communicated with the feeding riser, the feeding riser is communicated with a lower portion of the test bar cavity through the first feeding runner, the feeding riser is communicated with an upper portion of the test bar cavity through the second feeding runner, the bottom die is provided with a pouring gate, and the horizontal runner is communicated with the pouring gate.

[0005] Preferably, the test bar cavity, the first feeding runner, the feeding riser, the second feeding runner and the ingate are symmetrically arranged on both sides of the sprue respectively.

[0006] Preferably, the interior of the left mold and the right mold after mold closing also has venting channels, the first end of which is connected to the cavity of the test rod, and the second end of which is connected to the outside. More preferably, the interior of the left mold and the right mold after mold closing has several venting channels, the first ends of which are respectively connected to the cavity of the test rod, the feeding riser, and the sprue, and the second ends of which are respectively connected to the outside.

[0007] Preferably, the mold assembly includes a hinge, which is disposed on one side of the left mold and the right mold, and the left mold and the right mold are hinged together by the hinge.

[0008] Preferably, the mold assembly further includes a clamp, and the left mold and the right mold are respectively provided with a retaining shaft on the opposite side of the hinge. The first end of the clamp is movably connected to the retaining shaft on the left mold, and the second end of the clamp is provided with a locking slot, which is connected to the retaining shaft on the right mold.

[0009] Preferably, both the left mold and the right mold have a first positioning pin and a first positioning pin hole on their mating surfaces. The first positioning pin hole on the left mold is connected to the first positioning pin on the right mold, and the first positioning pin on the left mold is connected to the first positioning pin hole on the right mold.

[0010] Preferably, the mold further includes a cover plate, which is disposed on top of the left mold and the right mold after they are closed, and the cover plate is connected to the bottom mold by bolts.

[0011] Preferably, a filter plate is provided in the pouring port.

[0012] Preferably, the bottom mold is provided with a second positioning pin, and the bottom of the left mold and the right mold are respectively provided with second positioning pin holes, and the second positioning pin and the second positioning pin holes are connected in cooperation.

[0013] A second aspect of the present invention provides a method for forming a low-pressure metal tensile test bar, which uses the low-pressure metal tensile test bar forming mold described in the present invention to form a low-pressure metal tensile test bar.

[0014] Specifically, a method for forming a low-pressure metal tensile test bar includes the following steps:

[0015] The left and right molds are closed by rotating a hinge. The first positioning pin hole on the left mold is connected to the first positioning pin on the right mold, and the first positioning pin on the left mold is connected to the first positioning pin hole on the right mold.

[0016] Rotate the clamp on the left mold so that the clamp's slot connects with the clamp shaft on the right mold, locking and fixing the left and right molds together.

[0017] The locked left and right molds are placed on the bottom mold. The second positioning pin holes on the left and right molds are connected with the second positioning pin on the bottom mold. Then, the cover plate is placed on top of the left and right molds. The cover plate is connected to the bottom mold by bolts. Then, the filter sheet is placed in the pouring port of the bottom mold to assemble the low-pressure metal tensile test bar forming mold.

[0018] The low-pressure casting method is used. The pouring port of the low-pressure metal tensile test bar forming mold is aligned with the liquid riser. After liquid rise, mold filling, pressurization, pressure holding and pressure release, the low-pressure metal tensile test bar is obtained.

[0019] Preferably, the pressure of the liquid being pumped is 0.015-0.025 MPa; the pressure of the filling is 0.02-0.035 MPa; the pressure of the pressurization is 0.05-0.06 MPa and the time is 3-6 s; and the pressure holding time is 80-100 s.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The low-pressure metal tensile test bar forming mold provided by the present invention has a sprue and a feeding riser respectively located above the runner, and the sprue and feeding riser are respectively connected to the runner. The ingate and the test bar cavity are respectively located above the runner. The sprue is connected to the feeding riser through the ingate. The feeding riser is connected to the test bar through the first feeding runner and the second feeding runner. The bottom mold is provided with a pouring gate, and the runner is connected to the pouring gate. This allows the mold to be formed using low-pressure casting to obtain the test bar, which can more accurately reflect the actual performance of the casting.

[0022] The molding method for low-pressure metal mold tensile test bars provided by this invention ensures that the molding conditions of the test bars are consistent with those of low-pressure metal mold castings, enabling the molded test bars to more objectively evaluate whether the castings are qualified. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a front view structural schematic diagram of the low-pressure metal tensile test bar forming mold of the present invention.

[0025] Figure 2 This is a side view of the low-pressure metal tensile test bar forming mold of the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the low-pressure metal tensile test bar forming mold and the low-pressure casting equipment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of the low-pressure metal tensile test bar of the present invention.

[0028] In the diagram, 100-left mold, 110-right mold, 120-bottom mold, 121-sprue, 200-test bar cavity, 300-sprue, 310-sprue, 320-first shrinkage sprue, 330-shrinkage riser, 340-second shrinkage sprue, 350-ingate, 360-venting channel, 400-hinge, 500-clamp, 501-clamp, 600-clamping shaft, 700-first locating pin, 710-first locating pin hole, 800-cover plate, 900-filter plate. Detailed Implementation

[0029] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0031] In the description of this invention, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0032] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," "connect," and "several" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0033] Example 1

[0034] Reference Figure 1-2This embodiment provides a low-pressure metal tensile test bar forming mold, including a left mold 100, a right mold 110, and a bottom mold 120. The left mold 100 and right mold 110, after being closed by a mold-closing assembly, have a test bar cavity 200 and a gating channel. The gating channel includes a horizontal sprue 300, a sprue 310, a first feeding sprue 320, a feeding riser 330, a second feeding sprue 340, and an ingate 350. The sprue 310 and the feeding riser 330 are respectively located above the horizontal sprue 300. The sprue 350 and the test bar cavity 200 are respectively located above the sprue 300. The first end of the sprue 350 is connected to the sprue 310, and the second end of the sprue 350 is connected to the shrinkage riser 330. The shrinkage riser 330 is connected to the lower part of the test bar cavity 200 through the first shrinkage riser 320, and the shrinkage riser 330 is connected to the upper part of the test bar cavity 200 through the second shrinkage riser 340. The bottom mold 120 is provided with a pouring gate 121, and the sprue 300 is connected to the pouring gate 121.

[0035] In this embodiment, the test bar cavity 200, the first feeding runner 320, the feeding riser 330, the second feeding runner 340, and the ingate 350 are symmetrically arranged on both sides of the sprue 310. This symmetrical arrangement allows for the production of two test bars at once. Compared to molds that produce three or more test bars, producing too many test bars at once may affect the quality of the test bars. Therefore, this invention preferably produces two test bars at once.

[0036] In this embodiment, the interior of the left mold 100 and right mold 110 after mold closing also has several venting channels 360. The first ends of the venting channels 360 are respectively connected to the test bar cavity 200, the feeding riser 330, and the sprue 350, and the second ends of the venting channels 360 are respectively connected to the outside. By setting up venting channels, the smooth flow of molten metal is ensured, which can avoid the formation of porosity defects in the cavity due to poor venting in traditional molds, resulting in insufficient performance of the final test bar and affecting the evaluation of the casting.

[0037] In this embodiment, the mold closing assembly includes a hinge 400, which is disposed on one side of the left mold 100 and the right mold 110, and the left mold 100 and the right mold 110 are hinged together by the hinge 400. By providing the hinge, it is convenient for the left mold and the right mold to close together, and for the test rod to be opened and removed after the casting is complete.

[0038] In this embodiment, the mold-closing assembly further includes a clamp 500. The left mold 100 and right mold 110 each have a retaining pin 600 on their opposite sides from the hinge 400. The first end of the clamp 500 is movably connected to the retaining pin 600 on the left mold 100, and the second end of the clamp 500 has a locking slot 501, which connects to the retaining pin 600 on the right mold 110. By providing the clamp, the left and right molds can be better locked and fixed after mold closing.

[0039] In this embodiment, both the left mold 100 and the right mold 110 have a first positioning pin 700 and a first positioning pin hole 710 on their respective mold-closing surfaces. The first positioning pin hole 710 on the left mold 100 engages with the first positioning pin 700 on the right mold 110, and the first positioning pin 700 on the left mold 100 engages with the first positioning pin hole 710 on the right mold 110. By using the first positioning pin and the first positioning pin hole for positioning, misalignment after the left and right molds are closed can be avoided, ensuring that the test bar cavity and casting channel formed after mold closure will not deviate, thus guaranteeing the quality of the final test bar.

[0040] In this embodiment, a cover plate 800 is also included. The cover plate 800 is disposed on the top of the left mold 100 and the right mold 110 after they are closed. The cover plate 800 is connected to the bottom mold 120 by bolts.

[0041] In this embodiment, a filter 900 is provided in the pouring port 121. By providing the filter, impurities in the molten metal can be filtered during the liquid-lifting process, thus making the performance of the manufactured test bar closer to that of the casting.

[0042] In this embodiment, the bottom mold 120 is provided with a second positioning pin, and the bottom of the left mold 100 and the right mold 110 are respectively provided with second positioning pin holes. The second positioning pin and the second positioning pin holes are connected in cooperation. By setting the second positioning pin and the second positioning pin holes, the left mold, the right mold and the bottom mold are better positioned and fixed, thereby ensuring that the horizontal sprue after mold closing is aligned with the pouring gate of the bottom mold.

[0043] Unless otherwise specified, the raw materials used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0044] Example 2

[0045] This embodiment provides a method for forming a low-pressure metal tensile test bar. The low-pressure metal tensile test bar is obtained by using the forming mold of the low-pressure metal tensile test bar in Embodiment 1 and by low-pressure casting.

[0046] The specific molding method of this embodiment includes the following steps:

[0047] S1, Alloy Smelting:

[0048] The ZL114A aluminum alloy is melted, and when the temperature reaches 710℃, it is degassed and slag is removed. Then, the qualified alloy melt is poured into a holding furnace.

[0049] S2, Mold Assembly:

[0050] S2.1 Preheat the left mold, right mold and bottom mold at 320℃, spray conventional paint (raw materials include zinc oxide, water glass and water). In order to adjust the solidification sequence, spray more on the gate and riser that need to be fed with shrinkage, and spray less on the test bar cavity. Close the left mold and right mold by rotating the hinge. The first positioning pin hole on the left mold is connected with the first positioning pin on the right mold. The first positioning pin on the left mold is connected with the first positioning pin hole on the right mold.

[0051] S2.2 Rotate the clamp on the left mold so that the clamp's jaws connect with the clamp shaft on the right mold, locking and fixing the left and right molds;

[0052] S2.3 Place the locked and fixed left and right molds on the bottom mold. The second positioning pin holes on the left and right molds are connected with the second positioning pins on the bottom mold. Then place the cover plate on top of the left and right molds. The cover plate is connected to the bottom mold by bolts. Then place the filter sheet in the pouring port of the bottom mold to assemble the low-pressure metal tensile test bar forming mold.

[0053] S3, Low-pressure casting:

[0054] Reference Figure 3 ( Figure 3 In the diagram, A represents the clamping device, B represents the low-pressure casting equipment, C represents the riser inlet, and D represents the protective cover. The clamping device secures the assembled low-pressure metal tensile test bar forming mold to the low-pressure casting equipment, aligning the mold's pouring port with the riser inlet. The protective cover is then placed on top to prevent molten metal splashing. The process involves rising the metal, filling the mold, pressurizing, holding the pressure, and releasing the pressure. The mold is then opened, the sample is removed, the riser and gating gate are removed, the test bar is polished, and then heat-treated to obtain the low-pressure metal tensile test bar (see reference). Figure 4 The liquid lifting pressure is 0.021 MPa, the liquid lifting time is 12 s; the filling pressure is 0.029 MPa, the filling time is 7 s; the boosting pressure is 0.05 MPa, the boosting time is 3 s; and the holding time is 90 s.

[0055] The process of fixing the mold involves placing the fixing nut in the T-slot of the low-pressure casting equipment, placing the assembled low-pressure metal tensile test bar forming mold on the low-pressure casting equipment, and then using a clamping device to fix the assembled low-pressure metal tensile test bar forming mold on the low-pressure casting equipment by tightening the fixing bolts and fixing nut (see reference). Figure 3 ).

[0056] Example 3

[0057] The only difference between Example 3 and Example 2 is that: ZL101 aluminum alloy is used; the preheating temperature is 300℃; the liquid lifting pressure is 0.021MPa, the liquid lifting time is 12s; the filling pressure is 0.029MPa, the filling time is 7s; the pressurization pressure is 0.055MPa, the pressurization time is 3s; and the holding time is 80s. All other conditions are the same as in Example 2.

[0058] Example 4

[0059] The only difference between Example 4 and Example 2 is that: ZL104 aluminum alloy is used; the preheating temperature is 350℃; the liquid lifting pressure is 0.021MPa, the liquid lifting time is 12s; the filling pressure is 0.029MPa, the filling time is 7s; the pressurization pressure is 0.045MPa, the pressurization time is 3s; and the holding time is 100s. All other conditions are the same as in Example 2.

[0060] Comparative Example 1

[0061] The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 uses a conventional method to prepare a gravity metal tensile test bar (refer to GB / T1173-2013).

[0062] Comparative Example 2

[0063] The difference between Comparative Example 2 and Example 3 is that Comparative Example 2 uses a conventional method to prepare a gravity metal tensile test bar (refer to GB / T1173-2013).

[0064] Comparative Example 3

[0065] The difference between Comparative Example 3 and Example 4 is that Comparative Example 3 uses a conventional method to prepare a gravity metal tensile test bar (refer to GB / T1173-2013).

[0066] The test bars prepared in Examples 2-4 and Comparative Examples 1-3, as well as the main test bars 1-3 (which were processed from the sectioned test blocks of the aluminum alloy used in Examples 2-4, respectively), were subjected to room temperature tensile testing on a universal tensile testing machine at a tensile rate of 2 mm / min. The tensile mechanical properties are shown in Table 1 below:

[0067] Table 1

[0068] Example 2 348 281 7.6 qualified Example 3 329 252 9.8 qualified Example 4 312 241 5.7 qualified Comparative Example 1 326 256 6.7 qualified Comparative Example 2 312 243 8.9 qualified Comparative Example 3 304 229 4.2 Unqualified Body test stick 1 339 267 7.1 qualified Body test stick 2 323 246 8.2 qualified Body test stick 3 310 236 5.2 qualified

[0069] As can be seen from the data in Table 1, the tensile properties of the test bars prepared in Examples 2-4 are generally higher than those of the main test bars 1-3, while the main test bars 1-3 are higher than those of the gravity-cast test bars in Comparative Examples 1-3. Among them, the test bar prepared in Comparative Example 3 failed the performance test, but the corresponding main test bar passed, indicating that the gravity-cast test bars have a bias in evaluating low-pressure metal mold castings. The test bar in Example 4 of this invention passed, indicating that the test bars obtained by this invention have a good correspondence with low-pressure metal mold castings, can more accurately reflect the actual performance of the castings, and can more objectively evaluate whether the castings are qualified.

[0070] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A low-pressure metal tensile test bar forming mold, characterized in that, The system includes a left mold, a right mold, and a bottom mold. The left mold and the right mold, after being closed by a mold-closing assembly, have a test bar cavity and a gating channel. The gating channel includes a horizontal sprue, a vertical sprue, a first feeding sprue, a feeding riser, a second feeding sprue, and an ingate. The vertical sprue and the feeding riser are respectively located above the horizontal sprue and are connected to the horizontal sprue. The ingate and the test bar cavity are respectively located above the horizontal sprue. The first end of the ingate is connected to the vertical sprue, and the second end of the ingate is connected to the feeding riser. The feeding riser is connected to the lower part of the test bar cavity through the first feeding sprue and to the upper part of the test bar cavity through the second feeding sprue. The bottom mold has a gating gate, and the horizontal sprue is connected to the gating gate. The interior of the left mold and the right mold after they are closed also has an exhaust channel. The first end of the exhaust channel is connected to the cavity of the test rod, and the second end of the exhaust channel is connected to the outside.

2. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, The test bar cavity, the first feeding runner, the feeding riser, the second feeding runner, and the ingate are symmetrically arranged on both sides of the sprue.

3. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, The mold assembly includes a hinge, which is disposed on one side of the left mold and the right mold, and the left mold and the right mold are hinged together by the hinge.

4. The low-pressure metal tensile test bar forming die according to claim 3, characterized in that, The mold assembly further includes a clamp, and the left mold and the right mold are respectively provided with a clamping shaft on the opposite side of the hinge. The first end of the clamp is movably connected to the clamping shaft on the left mold, and the second end of the clamp is provided with a locking slot, which is connected to the clamping shaft on the right mold.

5. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, Both the left mold and the right mold have a first positioning pin and a first positioning pin hole on their mating surfaces. The first positioning pin hole on the left mold is connected to the first positioning pin on the right mold, and the first positioning pin on the left mold is connected to the first positioning pin hole on the right mold.

6. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, It also includes a cover plate, which is disposed on top of the left mold and the right mold after they are closed, and the cover plate is connected to the bottom mold by bolts.

7. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, A filter plate is provided in the pouring port.

8. The low-pressure metal tensile test bar forming die according to claim 1, characterized in that, The bottom mold is provided with a second positioning pin, and the bottom of the left mold and the right mold are respectively provided with a second positioning pin hole, and the second positioning pin and the second positioning pin hole are connected in cooperation.

9. A method for forming a low-pressure metal tensile test bar, characterized in that, The low-pressure metal tensile test bar forming mold as described in any one of claims 1-8 is used for forming. Includes the following steps: The left and right molds are closed by rotating a hinge. The first positioning pin hole on the left mold is connected to the first positioning pin on the right mold, and the first positioning pin on the left mold is connected to the first positioning pin hole on the right mold. Rotate the clamp on the left mold so that the clamp's slot connects with the clamp shaft on the right mold, locking and fixing the left and right molds together. The locked left and right molds are placed on the bottom mold. The second positioning pin holes on the left and right molds are connected with the second positioning pin on the bottom mold. Then, the cover plate is placed on top of the left and right molds. The cover plate is connected to the bottom mold by bolts. Then, the filter sheet is placed in the pouring port of the bottom mold to assemble the low-pressure metal tensile test bar forming mold. The low-pressure casting method is used. The pouring port of the low-pressure metal tensile test bar forming mold is aligned with the liquid riser. After liquid rise, mold filling, pressurization, pressure holding and pressure release, the low-pressure metal tensile test bar is obtained.

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