Casting cracking tendency evaluation device and method

Abstract

The invention discloses a casting cracking tendency evaluation device and method. The device comprises a casting mold and an electric control induction device. A pouring channel, a shrinkage limiting channel and a plurality of force measuring cavities are formed in the pouring mold, and the force measuring cavities communicate with the pouring channel and the shrinkage limiting channel correspondingly; each force measuring cavity comprises two end part sections and a middle contraction section communicated with the two end part sections, and the sizes of the middle contraction sections of the plurality of force measuring cavities are sequentially increased from top to bottom; the electric control induction device comprises a power module and a plurality of detection units connected with the power module in parallel, each detection unit comprises an indicator light and a detection wire, the detection wire comprises a detection section arranged in the middle contraction section of the corresponding force measurement cavity, and the indicator light and the power module form a closed loop through the detection wire. The evaluation method adopts the evaluation device, judges the cracking tendency through the extinguishing number of the indicator lamps, and has the advantages of being accurate in evaluation, high in practicability, convenient to operate, low in cost and the like.

Description

Technical Field

[0001] The present invention relates to the field of alloy casting, and particularly to an evaluation device and method for the tendency of casting cracking. Background Art

[0002] In modern industrial manufacturing, alloy castings have attracted much attention due to their excellent mechanical properties and wide application fields. With the continuous growth of the manufacturing industry's demand for high-performance, lightweight, and complex-structured components, the design of thin-walled, precise, and complex castings has gradually become the mainstream trend. However, during the alloy casting process, the cracking problem has always been one of the key bottlenecks restricting the improvement of the casting yield and quality. Cracking defects not only reduce the mechanical properties and service life of the castings but may also lead to the scrapping of the entire casting, thus significantly increasing the production cost. Especially in large and complex castings or thin-walled castings, due to the uneven distribution of thermal stress during the solidification and cooling processes, the cracking problem is more prominent. Therefore, how to effectively predict and control the cracking tendency of castings has become a research hotspot in the current alloy casting field.

[0003] Currently, the research on the cracking problem during the alloy casting process mainly focuses on two aspects: one is to improve the crack resistance of materials by regulating the alloy composition, such as optimizing the alloy element ratio to enhance its high-temperature strength and plasticity; the other is to reduce the generation of thermal stress and residual stress by optimizing the casting process parameters (such as pouring temperature, pouring speed, mold design, etc.). In addition, the existing technologies also include some experimental evaluation methods for evaluating the alloy's fluidity and hot cracking resistance, such as the hot cracking ring test, the constrained bar test, etc. These methods can, to a certain extent, reflect the cracking tendency of the alloy under high-temperature conditions and provide a reference basis for the optimization of the casting process.

[0004] Although the existing technologies can evaluate the casting performance of alloys to a certain extent, there are still obvious limitations. First, the method of directly using product casting for experiments can truly reflect the actual cracking behavior of the castings, but its cost is high and the cycle is long, making it difficult to meet the requirements of rapid R & D. Second, the existing laboratory evaluation methods mainly focus on the tests of alloy fluidity and hot cracking resistance, and pay insufficient attention to low-temperature cracking behaviors such as cold cracking, and cannot comprehensively evaluate the cracking tendency of castings at different temperature stages. In addition, the existing methods often only analyze a single factor (such as thermal stress or shrinkage behavior) and lack the comprehensive evaluation ability of the cracking behavior under the coupling action of multiple factors. This limitation restricts the R & D efficiency of new alloys and new processes and is difficult to meet the requirements of the modern casting industry for efficient and accurate evaluation methods. Therefore, there is an urgent need to develop an efficient evaluation method that can comprehensively consider various cracking mechanisms to better guide alloy design and casting process optimization. Summary of the Invention

[0005] In order to evaluate the cracking tendency during the solidification process of castings, the present invention provides a device and method for the casting cracking tendency.

[0006] To achieve the above object, the technical solution of the present invention is as follows: It includes a pouring mold and an electric control induction device;

[0007] The pouring mold is provided with a pouring channel and a constriction channel extending along a first direction, and a plurality of force measuring cavities distributed along a second direction. The plurality of force measuring cavities are respectively communicated with the pouring channel and the constriction channel, and the first direction and the second direction are perpendicular to each other;

[0008] Each force measuring cavity includes two end segments arranged along the second direction and an intermediate constriction segment connecting the two end segments. The cross-sectional area of the intermediate constriction segment is smaller than that of the end segments, and the dimensions of the intermediate constriction segments of the plurality of force measuring cavities along the first direction increase sequentially from top to bottom;

[0009] The electric control induction device includes a power supply module and a plurality of detection units arranged in parallel with the power supply module. Each detection unit includes an indicator light and a detection wire with an insulating coating layer. The detection wire includes a detection section, and the detection section is arranged in the intermediate constriction segment of the corresponding force measuring cavity. The indicator light forms a closed loop with the power supply module through the detection wire, and the number of detection units corresponds one-to-one with the force measuring cavities.

[0010] In a possible embodiment, the detection section of the detection wire includes a predetermined fracture section, the predetermined fracture section extends along the second direction, and the stress concentration area of the intermediate constriction segment is arranged within the area of the predetermined fracture section.

[0011] In a possible embodiment, a plurality of spacer plates are arranged in the middle of the pouring mold, and the area between the pouring channel and the constriction channel is divided by the spacer plates to form a plurality of the force measuring cavities.

[0012] In a possible embodiment, a partial section of the detection wire connected to the detection section is buried in the spacer plate at the corresponding force measuring cavity.

[0013] In a possible embodiment, a pouring port and an exhaust port are provided at the top of the pouring mold. The pouring port is communicated with the pouring channel, and the exhaust port is communicated with the constriction channel.

[0014] The present invention also provides a method for evaluating the casting cracking tendency, which is evaluated by the above-mentioned device for evaluating the casting cracking tendency, and includes the following steps:

[0015] Connect the power supply module of the electric control induction device and confirm that each indicator light is lit;

[0016] Preheat the casting mold to a preset mold temperature;

[0017] Inject the molten metal into the casting mold at a preset pouring temperature, so that the molten metal flows into the pouring channel, the constriction channel and a plurality of force measuring cavities;

[0018] During the solidification and cooling process of the molten metal, the stress concentration state of the middle constriction section of each force measuring cavity is monitored in real time, specifically including:

[0019] When the middle constriction section of a certain force measuring cavity breaks due to the accumulation of thermal stress, pull off the corresponding detection wire to turn off the corresponding indicator light;

[0020] Compare and analyze the number of extinguished indicator lights when the middle constriction section of the corresponding force measuring cavity breaks under the conditions of preset pouring temperature and preset mold temperature for different alloy materials, and evaluate the casting cracking tendency of the alloy.

[0021] Among them, determine the fracture level according to the number of extinguished indicator lights, and evaluate the casting cracking tendency of the alloy, specifically including:

[0022] Determine the fracture level according to the number of extinguished indicator lights. When the number of extinguished indicator lights is N, the fracture level is N level. The higher the fracture level, the greater the cracking tendency of the alloy.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Through the design of a plurality of force measuring cavities with a gradient increase in the first direction, the evaluation method is similar to the actual fracture process of the casting, and various fracture modes such as hot cracking and cold cracking can be evaluated.

[0025] (2) The predetermined fracture section of the detection wire corresponds precisely to the stress concentration area of the force measuring cavity, ensuring that the wire fracture behavior is synchronized with the alloy cracking in real time, eliminating the lag error of traditional indirect detection, and improving the evaluation accuracy.

[0026] (3) The casting stress can be evaluated by the alloy with a fractured middle constriction section. Based on the extinguished state and position information of the indicator light, the fracture sequence and stress level of different force measuring cavities can be directly reflected, realizing a rapid visual judgment of the cracking tendency and reducing the complexity of data analysis. Description of the Drawings

[0027] Figure 1 It is a schematic cross-sectional view of the overall model of the device of the present invention.

[0028] In the figure: 1. Casting mold; 11. Pouring gate; 12. Force measuring cavity; 12a. End section; 12b. Middle constriction section; 13. Exhaust port; 14. Spacer; 2. Electric control induction device; 21. Detection wire; 21a. Detection section; 22. Power supply module; 23. Indicator light. Specific Embodiment

[0029] As Figure 1 shown, this embodiment provides a device for evaluating the tendency of casting cracking, including a pouring mold 1 and an electric control induction device 2.

[0030] In some embodiments, the pouring mold 1 can be designed into a rectangular structure, and its inner cavity has a rectangular inner cavity. A pouring port 11 and an exhaust port 13 are opened at the top of the pouring mold 1. Among them, a pouring channel is below the pouring port 11, and the pouring port 11 communicates with the pouring channel extending along the length direction of the pouring mold 1. Among them, a constriction channel is arranged below the exhaust port 13, and the exhaust port 13 communicates with the constriction channel extending along the length direction of the pouring mold 1. The pouring channel and the constriction channel are respectively arranged on one side of the inner cavity of the pouring mold 1. A plurality of spacer plates 14 are fixedly arranged along the length direction of the pouring mold 1 in the area between the two. Through the division of the plurality of spacer plates 14, a plurality of force-measuring cavities 12 are formed in the middle area of the pouring mold 1. The force-measuring cavity 12 includes two end segments 12a and an intermediate constriction segment 12b for connecting the two end segments 12a, and the overall structure is similar to a dumbbell shape. This intermediate constriction segment 12b is the stress concentration area during pouring.

[0031] Referring to Figure 1 , in some embodiments, by setting the vertical distance of the spacer plates 14, the size of the intermediate constriction segment of the force-measuring cavity 12 gradually increases from top to bottom, forming a gradient. Optionally, the shape of the spacer plate 14 is such that the size of the middle area is large and the sizes of the two end areas are small.

[0032] In some alternative embodiments, the electric control induction device 2 includes a power supply module 22 and a plurality of detection units arranged in parallel with the power supply module 22. Each detection unit includes an indicator light 23 and a detection wire 21 with an insulating coating layer. The detection section 21a of the detection wire 21 is arranged in the intermediate constriction segment 12b of the corresponding force-measuring cavity 12. The indicator light 23 and the power supply module 22 form a closed loop through the detection wire 21, and the number of detection units corresponds one-to-one with the force-measuring cavity 12.

[0033] In some possible embodiments, a partial section of the detection wire 21 connected to the detection section 21a is buried in the spacer plate 14 at the corresponding force-measuring cavity 12. Optionally, the pouring mold 1 is a split part with a two-half structure, and a wire groove is opened on the middle section plane of the two halves, and the detection wire 21 is arranged in the wire groove.

[0034] The detection section 21a includes a predetermined fracture section that transversely crosses the stress concentration area of the intermediate contraction section 12b along the second direction. That is, the length of the predetermined fracture section needs to be greater than the length of the stress concentration area of the intermediate contraction section 12b, and the stress concentration area should be set within the predetermined fracture section. When the stress concentration area fractures, it can cause the wire of the predetermined fracture section within the intermediate contraction section 12b to break.

[0035] In some embodiments, the predetermined fracture section of the detection wire 21 uses a high-temperature resistant and easily breakable wire. Optionally, the matrix of the predetermined fracture section of the detection wire 21 uses fine copper wire, and an Al2O3 ceramic layer is formed on the surface of the wire of the predetermined fracture section by means of plasma spraying.

[0036] In another embodiment, a method for evaluating the casting cracking tendency is also provided. This evaluation method uses the casting cracking tendency evaluation device in the above example and includes the following steps:

[0037] Connect the power module of the electric control induction device and confirm that each indicator light is lit;

[0038] Preheat the casting mold to the preset mold temperature;

[0039] Inject the molten metal into the casting mold at the preset pouring temperature, so that the molten metal flows into the pouring channel, the constriction channel, and the multiple force measuring cavities;

[0040] During the solidification and cooling process of the molten metal, the stress concentration state of the intermediate contraction section of each force measuring cavity is monitored in real time, specifically including:

[0041] When the intermediate contraction section of a certain force measuring cavity fractures due to the accumulation of thermal stress, trigger the fracture of the corresponding detection wire to turn off the corresponding indicator light;

[0042] Compare and analyze the number of indicator lights turned off when the intermediate contraction sections of each force measuring cavity fracture under the conditions of the preset pouring temperature and the preset mold temperature for different alloy materials, and evaluate the casting cracking tendency of the alloy. Determine the fracture level according to the number of indicator lights turned off. When the number of indicator lights turned off is N, the fracture level is N level. The lower the fracture level, the smaller the cracking tendency of the alloy.

[0043] The present invention will be further described in conjunction with the following specific embodiments, but the present invention is not limited thereto.

[0044] Embodiment 1

[0045] Design and preparation of a casting mold. The pouring gate 11 is in the shape of a hollow inverted frustum. Ten groups of cylindrical cavities are arranged on both sides from top to bottom in the middle of the casting mold 1. The size of a single cavity is φ20×100 mm, and they are connected by intermediate channels with different diameters in the middle. The length of the intermediate contraction section 12b is 20 mm, and the diameters are φ3 mm, φ4 mm, φ5 mm, φ6 mm, φ7 mm, φ8 mm, φ9 mm, φ10 mm, φ11 mm, φ12 mm respectively. The intermediate contraction section 12b is connected to the cylindrical cavities on both sides in an arc shape. The intermediate contraction section 12b corresponds to the fracture levels Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, Ⅷ, Ⅸ, Ⅹ from small to large. If the alloy fractures without the intermediate contraction section, it is defined as level 0. A detection wire 21 with an insulating coating passes through the center of the intermediate contraction section 12b and is connected to an external power supply module 22 and an indicator light 23. The thickness of the right-side restricted contraction area is 20 mm, and it is connected to the outside through the exhaust port 13.

[0046] During the experiment, the Mg-Gd-Y-Zr series alloy melt is poured into the pouring gate at temperature T1. Before alloy casting, the casting mold is preheated to temperature T2, and the power supply of the electro-control induction device is turned on, and ten indicator lights light up. After casting is completed, observe the indicator lights and record the extinguishing situation of each indicator light until no more indicator lights go out. If the first indicator light goes out and the second indicator light does not go out, then the fracture level is determined to be Ⅰ, and so on. Under the same material, the smaller the fracture level, the smaller the thermal stress. The specific experimental data are shown in Table 1.

[0047] Table 1 Statistics of cracking levels of Mg-Gd-Y-Zr series alloy after casting

[0048] Serial number Alloy Pouring temperature T1 (°C) Mold temperature T2(°C) Fracture level 1 Mg-6Gd-3Y-Zr 700 ℃ 200 ℃ Ⅳ 2 Mg-6Gd-3Y-Zr 725 ℃ 200 ℃ Ⅴ 3 Mg-6Gd-3Y-Zr 750 ℃ 200 ℃ Ⅵ 4 Mg-6Gd-3Y-Zr 750 ℃ 300 ℃ Ⅳ 5 Mg-6Gd-3Y-Zr 750℃ 400 ℃ Ⅲ 6 Mg-8Gd-3Y-Zr 700 ℃ 300 ℃ Ⅴ 7 Mg-8Gd-3Y-Zr 750 ℃ 300 ℃ Ⅵ 8 Mg-8Gd-3Y-Zr 800℃ 300 ℃ Ⅶ 9 Mg-8Gd-3Y-Zr 700 ℃ 200 ℃ Ⅵ 10 Mg-8Gd-3Y-Zr 700 ℃ 400 ℃ Ⅳ 11 Mg-9Gd-4Y-Zr 700 ℃ 200 ℃ Ⅶ 12 Mg-9Gd-4Y-Zr 750 ℃ 200 ℃ Ⅷ 13 Mg-9Gd-4Y-Zr 800 ℃ 200 ℃ Ⅸ 14 Mg-9Gd-4Y-Zr 700 ℃ 300 ℃ Ⅷ 15 Mg-9Gd-4Y-Zr 700 ℃ 400 ℃ Ⅵ

[0049] From the data in Table 1, it can be seen that for the Mg-6Gd-3Y-Zr alloy, when the casting temperature (T1) is 750 °C and the mold temperature (T2) is 400 °C, the fracture level is Ⅲ, which is the casting process with the smallest cracking tendency for this alloy; for the Mg-8Gd-3Y-Zr alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 400 °C, the fracture level is Ⅳ, which is the casting process with the smallest cracking tendency for this alloy; for the Mg-9Gd-4Y-Zr alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 400 °C, the fracture level is Ⅵ, which is the casting process with the smallest cracking tendency for this alloy. For the three tested Mg-Gd-Y-Zr series alloys, the Mg-6Gd-3Y-Zr alloy has the smallest cracking tendency, and the smallest fracture level is Ⅲ.

[0050] Example 2

[0051] Example 2 uses a Mg-Al-Zn series alloy melt, and the rest is the same as in Example 1. The specific experimental data are shown in Table 2.

[0052] Table 2 Statistics of the cracking grade and temperature of the Mg-Al-Zn series alloy after casting

[0053] Serial number Alloy Pouring temperature T1 (°C) Mold temperature T2(°C) Fracture level 1 AZ31 700 ℃ 200 ℃ Ⅰ 2 AZ31 750 ℃ 200 ℃ Ⅱ 3 AZ31 800 ℃ 200 ℃ Ⅲ 4 AZ31 700 ℃ 250 ℃ Ⅱ 5 AZ31 700 ℃ 300 ℃ Ⅰ 6 AZ61 700 ℃ 200 ℃ Ⅲ 7 AZ61 750 ℃ 200 ℃ Ⅲ 8 AZ61 800 ℃ 200 ℃ Ⅳ 9 AZ61 700 ℃ 300 ℃ Ⅱ 10 AZ61 700 ℃ 400 ℃ Ⅱ 11 AZ91 700 ℃ 200 ℃ Ⅳ 12 AZ91 750 ℃ 200 ℃ Ⅴ 13 AZ91 800 ℃ 200 ℃ Ⅴ 14 AZ91 700 ℃ 300 ℃ Ⅳ 15 AZ91 700 ℃ 400 ℃ Ⅲ

[0054] From the data in Table 2, it can be seen that for the AZ31 alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 200 °C - 300 °C (Serial numbers 1 and 5), the fracture grade is Grade I, which is the casting process with the least cracking tendency for this alloy; for the AZ61 alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 400 °C, the fracture grade is Grade II, which is the casting process with the least cracking tendency for this alloy; for the AZ91 alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 400 °C, the fracture grade is Grade III, which is the casting process with the least cracking tendency for this alloy. For the three Mg-Al-Zn series alloys tested, the AZ31 alloy has the least cracking tendency, and the minimum fracture grade is Grade I.

[0055] Example 3

[0056] Example 3 uses an Al-Cu series alloy melt, and the rest is the same as in Example 1. The specific experimental data are shown in Table 3.

[0057] Table 3 Statistics of the cracking grade and temperature of the Al-Cu series alloy after casting

[0058] Serial number Alloy Pouring temperature T1 (°C) Mold temperature T2(°C) Fracture level 1 ZL201 700 ℃ 200 ℃ Ⅲ 2 ZL201 725 ℃ 200 ℃ Ⅳ 3 ZL201 750 ℃ 200 ℃ Ⅴ 4 ZL201 700 ℃ 250 ℃ Ⅲ 5 ZL201 700℃ 300 ℃ Ⅱ 6 ZL205 700 ℃ 250 ℃ Ⅳ 7 ZL205 725 ℃ 250 ℃ Ⅴ 8 ZL205 750 ℃ 250 ℃ Ⅵ 9 ZL205 700 ℃ 300 ℃ Ⅳ 10 ZL205 700 ℃ 400 ℃ Ⅲ

[0059] From the data in Table 3, it can be seen that for the ZL201 alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 300 °C, the fracture grade is Grade II, which is the casting process with the least cracking tendency for this alloy; for the ZL205 alloy, when the casting temperature (T1) is 700 °C and the mold temperature (T2) is 400 °C, the fracture grade is Grade III, which is the casting process with the least cracking tendency for this alloy. For the two Al-Cu series alloys tested, the ZL201 alloy has the least cracking tendency, and the minimum fracture grade is Grade II.

[0060] It should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or modify some or all of the technical solutions, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A casting cracking tendency assessment device, characterized in that: It includes a casting mold and an electric control sensing device; The casting mold is provided with a casting channel and a shrinkage channel extending along a first direction, and a plurality of force measuring cavities distributed along a second direction, the plurality of force measuring cavities are respectively connected to the casting channel and the shrinkage channel, and the first direction is perpendicular to the second direction; Each force measuring cavity comprises two end sections arranged along the second direction and a middle contraction section connecting the two end sections, the cross-sectional area of ​​the middle contraction section is smaller than the cross-sectional area of ​​the end section, and the size of the middle contraction sections of the force measuring cavities along the first direction increases from top to bottom; The electrically controlled sensing device includes a power module and a plurality of detection units arranged in parallel with the power module, each of the detection units includes an indicator light and a detection wire having an insulating coating layer, the detection wire includes a detection section, and the detection section is arranged in the middle contraction section of the corresponding force measuring cavity. The indicator light forms a closed loop with the power module through the detection wire, and the number of detection units is in a one-to-one correspondence with the force measuring cavity.

2. The casting crack tendency assessment device according to claim 1, characterized in that: The detection section of the detection wire comprises a predetermined breaking section, the predetermined breaking section extends along the second direction, and the stress concentration area of ​​the middle contraction section is arranged in the area of ​​the predetermined breaking section.

3. The casting crack tendency assessment device according to claim 1, characterized in that: A plurality of spacer plates are arranged in the middle of the casting mold, and the area between the casting channel and the contraction channel is divided by the spacer plates to form a plurality of force measuring cavities.

4. The casting crack tendency assessment device according to claim 3, characterized in that: Partial sections of the detection wire connected to the detection section are buried in the spacer plate corresponding to the force measuring cavity.

5. The casting crack tendency assessment device according to claim 1, characterized in that: A pouring port and an exhaust port are provided on the top of the pouring mold. The pouring port is communicated with the pouring channel, and the exhaust port is communicated with the shrinkage channel.

6. A method for evaluating casting cracking tendency, characterized in that: The evaluation is performed by the casting cracking tendency evaluation device according to any one of claims 1 to 5, comprising the following steps: Connect the power module of the electric control induction device and confirm that all indicator lights are on; Preheating the casting mold to a preset mold temperature; Injecting molten metal into the casting mold at a preset casting temperature, so that the molten metal flows into the casting channel, the shrinkage channel and the multiple force measuring cavities; During the solidification and cooling process of the molten metal, the stress concentration state of the middle contraction section of each force measuring cavity is monitored in real time, including: When the middle contraction section of a force measuring cavity breaks due to the accumulation of thermal stress, the corresponding detection wire is pulled off to turn off the corresponding indicator light; The number of indicator lights that go off when the middle contraction section of the force measuring cavity breaks is compared and analyzed for different alloy materials under preset pouring temperature and preset mold temperature conditions, so as to evaluate the casting cracking tendency of the alloy.

7. The casting crack tendency assessment method according to claim 6, characterized in that: Evaluate the alloy's casting cracking tendency, including: The fracture level is determined according to the number of indicator lights that are extinguished. When the number of indicator lights that are extinguished is N, the fracture level is N. The higher the fracture level, the greater the tendency of the alloy to crack.

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