Casting cracking propensity assessment apparatus and method

Abstract

The application discloses a casting cracking tendency evaluation device and method. The device comprises a pouring mold and an electric control induction device. The pouring mold is internally provided with a pouring channel, a shrinkage limiting channel, and a plurality of force measuring cavities. The plurality of force measuring cavities are respectively communicated with the pouring channel and the shrinkage limiting channel. Each force measuring cavity comprises two end sections and an intermediate shrinkage section connecting the two end sections. The sizes of the intermediate shrinkage sections of the plurality of force measuring cavities increase from top to bottom. The electric control induction device comprises a power module and a plurality of detection units arranged in parallel with the power module. Each detection unit comprises an indicator lamp and a detection lead. The detection lead comprises a detection section arranged in the intermediate shrinkage section of the corresponding force measuring cavity. The indicator lamp and the power module form a closed loop through the detection lead. The evaluation method adopts the above evaluation device. The number of extinguished indicator lamps is used to determine the cracking tendency. The method has the advantages of accurate evaluation, strong practicability, convenient operation, low cost and the like.

Description

Technical Field

[0001] This invention relates to the field of alloy casting, and in particular to a device and method for evaluating the tendency of casting to crack. Background Technology

[0002] In modern industrial manufacturing, alloy castings have attracted much attention due to their excellent mechanical properties and wide range of applications. With the increasing demand for high-performance, lightweight, and complex structural components in the manufacturing industry, thin-walled, precision, and complex casting designs are gradually becoming the mainstream trend. However, cracking remains a key bottleneck restricting the yield and quality improvement of castings during alloy casting. Cracking defects not only reduce the mechanical properties and service life of castings but can also lead to the scrapping of the entire casting, significantly increasing production costs. This is especially true for large, complex castings or thin-walled castings, where uneven distribution of thermal stress during solidification and cooling exacerbates the cracking problem. Therefore, effectively predicting and controlling the cracking tendency of castings has become a current research hotspot in the field of alloy casting.

[0003] Currently, research on cracking during alloy casting mainly focuses on two aspects: first, improving the crack resistance of materials by controlling alloy composition, such as optimizing the alloy element ratio to enhance high-temperature strength and plasticity; second, reducing the generation of thermal stress and residual stress by optimizing casting process parameters (such as pouring temperature, pouring speed, and mold design). In addition, existing technologies include experimental evaluation methods to assess the alloy's fluidity and resistance to hot cracking, such as hot crack ring tests and constraint bar tests. These methods can reflect the cracking tendency of alloys under high-temperature conditions to a certain extent, providing a reference for optimizing the casting process.

[0004] While existing technologies can evaluate the casting properties of alloys to some extent, they still have significant limitations. First, while directly testing with product castings can accurately reflect the actual cracking behavior of castings, it is costly and time-consuming, making it difficult to meet the needs of rapid research and development. Second, existing laboratory evaluation methods mainly focus on testing alloy fluidity and resistance to hot cracking, while paying insufficient attention to low-temperature cracking behaviors such as cold cracking, failing to comprehensively assess the cracking tendency of castings at different temperature stages. Furthermore, existing methods often analyze only a single factor (such as thermal stress or shrinkage behavior), lacking the ability to comprehensively evaluate cracking behavior under the coupled effects of multiple factors. These limitations restrict the efficiency of developing new alloys and processes, making it difficult to meet the demands 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 multiple cracking mechanisms to better guide alloy design and casting process optimization. Summary of the Invention

[0005] To evaluate the tendency of castings to crack during solidification, this invention provides a casting cracking tendency device and method.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: it includes a casting mold and an electronically controlled induction device;

[0007] 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 and the second direction are perpendicular to each other.

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

[0009] The electronically controlled sensing device includes a power module and multiple detection units connected in parallel with the power module. Each detection unit includes an indicator light and a detection wire with an insulating coating. The detection wire includes a detection section, which is located 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 corresponds one-to-one with the force measuring cavity.

[0010] In one possible embodiment, the detection segment of the detection wire includes a predetermined fracture segment extending along a second direction, and the stress concentration area of ​​the intermediate contraction segment is located within the area of ​​the predetermined fracture segment.

[0011] In one possible embodiment, the middle of the casting mold is provided with a plurality of partition plates, and the area between the casting channel and the constriction channel is divided by the partition plates to form a plurality of force measuring cavities.

[0012] In one possible embodiment, a portion of the detection wire connected to the detection segment is embedded in a spacer at the corresponding force measuring cavity.

[0013] In one possible embodiment, the top of the casting mold is provided with a pouring port and a vent, the pouring port is connected to the pouring channel, and the vent is connected to the constriction channel.

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

[0015] Turn on the power module of the electronically controlled sensing device and confirm that all indicator lights are lit.

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

[0017] Molten metal is injected into the casting mold at a preset casting temperature, allowing the molten metal to flow into the casting channel, the constriction channel, and multiple force measuring chambers;

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

[0019] When the middle contraction section of a force measuring cavity breaks due to accumulated thermal stress, the corresponding detection wire is pulled off to extinguish the corresponding indicator light.

[0020] By comparing and analyzing the number of indicator lights that go out when the middle contraction section of the force measuring cavity fractures under preset pouring temperature and preset mold temperature conditions for different alloy materials, the casting cracking tendency of the alloys can be evaluated.

[0021] The fracture level is determined based on the number of indicator lights that go out, and the casting cracking tendency of the alloy is assessed. Specifically, this includes:

[0022] The fracture level is determined by the number of indicator lights that are off. When the number of off indicator lights is N, the fracture level is N. The higher the fracture level, the greater the tendency of the alloy to crack.

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

[0024] (1) By designing multiple force measuring cavities with a gradient increasing along 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 and alloy cracking are synchronized in real time, eliminating the lag error of traditional indirect detection and improving the accuracy of evaluation.

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

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

[0028] In the diagram: 1. Casting mold; 11. Casting gate; 12. Force measuring chamber; 12a. End section; 12b. Intermediate shrinkage section; 13. Vent; 14. Spare plate; 2. Electrically controlled sensing device; 21. Detection wire; 21a. Detection section; 22. Power module; 23. Indicator light. Detailed Implementation

[0029] like Figure 1 As shown, this embodiment provides a casting cracking tendency assessment device, including a casting mold 1 and an electronically controlled induction device 2.

[0030] In some embodiments, the casting mold 1 can be designed as a rectangular structure with a rectangular inner cavity. A pouring port 11 and a vent 13 are provided at the top of the casting mold 1. Below the pouring port 11 is a pouring channel, which communicates with the pouring port 11 extending along the length of the casting mold 1. Below the vent 13 is a constriction channel, which communicates with the constriction channel extending along the length of the casting mold 1. The pouring channel and the constriction channel are respectively located on one side of the inner cavity of the casting mold 1. Multiple spacers 14 are fixedly arranged along the length of the casting mold 1 in the area between them. Through the division by the multiple spacers 14, multiple force-measuring cavities 12 are formed in the middle region of the casting mold 1. Each force-measuring cavity 12 includes two end sections 12a and a middle contraction section 12b connecting the two end sections 12a, with an overall structure resembling a dumbbell shape. This middle constriction section 12b is a stress concentration area during casting.

[0031] refer to Figure 1 In some embodiments, by setting the vertical distance between the spacer 14, the size of the middle contraction section of the force measuring cavity 12 gradually increases from top to bottom, forming a gradient. Optionally, the spacer 14 has a shape with a large size in the middle region and small sizes at both ends.

[0032] In some optional embodiments, the electronically controlled sensing device 2 includes a power module 22 and a plurality of detection units arranged in parallel with the power module 22. Each detection unit includes an indicator light 23 and a detection wire 21 with an insulating coating. The detection section 21a of the detection wire 21 is arranged in the middle contraction section 12b of the corresponding force measuring cavity 12. The indicator light 23 forms a closed loop with the power module 22 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 portion of the detection wire 21 connected to the detection section 21a is embedded in the spacer 14 at the corresponding force measuring cavity 12. Optionally, the casting mold 1 is a two-half structure assembly, with a groove formed on the middle cut surface of the two halves, and the detection wire 21 is disposed in the groove.

[0034] The detection section 21a includes a predetermined fracture section that traverses the stress concentration area of ​​the intermediate contraction section 12b along a 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 located within the predetermined fracture section. When a fracture occurs in the stress concentration area, the conductor in the predetermined fracture section within the intermediate contraction section 12b will break.

[0035] In some embodiments, the predetermined fracture segment of the detection wire 21 is made of a high-temperature resistant, easily broken wire. Optionally, the substrate of the predetermined fracture segment of the detection wire 21 is made of fine copper wire, and an Al2O3 ceramic layer is formed on the surface of the wire of the predetermined fracture segment using a plasma spraying process.

[0036] In another embodiment, a casting cracking tendency assessment method is also provided, which uses the casting cracking tendency assessment device in the above examples and includes the following steps:

[0037] Turn on the power module of the electronically controlled sensing device and confirm that all indicator lights are lit.

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

[0039] Molten metal is injected into the casting mold at a preset casting temperature, allowing the molten metal to flow into the casting channel, the constriction channel, and multiple force measuring chambers;

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

[0041] When the middle contraction section of a force measuring cavity breaks due to accumulated thermal stress, it triggers the breakage of the corresponding detection wire, causing the corresponding indicator light to turn off.

[0042] By comparing and analyzing the number of indicator lights extinguished when fracture occurred in the middle contraction section of each force measuring cavity under preset pouring and mold temperatures for different alloy materials, the casting cracking tendency of the alloys was assessed. The fracture level was determined based on the number of indicator lights extinguished. When the number of indicator lights extinguished was N, the fracture level was N. The lower the fracture level, the lower the tendency of the alloy to crack.

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

[0044] Example 1

[0045] The casting mold 1 is designed and manufactured with a hollow inverted frustum-shaped gate 11. Ten sets of cylindrical cavities are arranged on both sides of the center of the casting mold 1 from top to bottom. Each cavity has a size of φ20×100mm and is connected by intermediate channels of different diameters. The length of the intermediate contraction section 12b is 20mm, and its diameters are φ3mm, φ4mm, φ5mm, φ6mm, φ7mm, φ8mm, φ9mm, φ10mm, φ11mm, and φ12mm, respectively. The intermediate contraction section 12b is connected to the cylindrical cavities on both sides by an arc. The intermediate contraction section 12b, from smallest to largest, corresponds to fracture levels I, II, III, IV, V, VI, VII, VIII, IX, and X. If there is no alloy fracture in the intermediate contraction section, it is defined as level 0. An insulating-coated detection wire 21 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 right-side restricted contraction zone is 20mm thick and is connected to the outside through the exhaust port 13.

[0046] During the experiment, the Mg-Gd-Y-Zr alloy melt was poured into the gate at temperature T1. Before pouring, the casting mold was preheated to temperature T2, and the power supply to the electronically controlled induction device was turned on, illuminating 10 indicator lights. After pouring, the indicator lights were observed, and the status of each indicator light being off was recorded until no indicator light was extinguished. If the first indicator light was extinguished but the second indicator light was not extinguished, the fracture level was determined to be I, and so on. For the same material, the smaller the fracture level, the smaller the thermal stress. Table 1 shows the specific experimental data.

[0047] Table 1. Statistics on crack levels after casting of Mg-Gd-Y-Zr alloys

[0048] 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] As shown in Table 1, the Mg-6Gd-3Y-Zr alloy exhibits a fracture grade of III at a casting temperature (T1) of 750℃ and a mold temperature (T2) of 400℃, representing the casting process with the lowest cracking tendency. Similarly, the Mg-8Gd-3Y-Zr alloy exhibits a fracture grade of IV at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 400℃, also representing the casting process with the lowest cracking tendency. Furthermore, the Mg-9Gd-4Y-Zr alloy exhibits a fracture grade of VI at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 400℃, representing the casting process with the lowest cracking tendency. Among the three Mg-Gd-Y-Zr alloys tested, the Mg-6Gd-3Y-Zr alloy exhibits the lowest cracking tendency, with the lowest fracture grade being III.

[0050] Example 2

[0051] Example 2 used a Mg-Al-Zn alloy melt, and the rest was the same as in Example 1. Table 2 shows the specific experimental data.

[0052] Table 2. Statistics on crack order and temperature after casting of Mg-Al-Zn alloys

[0053] 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] As shown in Table 2, the AZ31 alloy exhibits a fracture grade of I at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 200℃-300℃ (numbers 1 and 5), representing the casting process with the lowest cracking tendency for this alloy. The AZ61 alloy exhibits a fracture grade of II at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 400℃, also representing the casting process with the lowest cracking tendency for this alloy. The AZ91 alloy exhibits a fracture grade of III at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 400℃, representing the casting process with the lowest cracking tendency for this alloy. Among the three Mg-Al-Zn alloys tested, the AZ31 alloy exhibits the lowest cracking tendency, with the lowest fracture grade being I.

[0055] Example 3

[0056] Example 3 used an Al-Cu alloy melt, and the rest was the same as in Example 1. Table 3 shows the specific experimental data.

[0057] Table 3. Statistics on crack order and temperature after casting of Al-Cu alloys

[0058] 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] As shown in Table 3, the ZL201 alloy exhibits a fracture grade of II at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 300℃, representing the casting process with the lowest cracking tendency for this alloy. Similarly, the ZL205 alloy exhibits a fracture grade of III at a casting temperature (T1) of 700℃ and a mold temperature (T2) of 400℃, also representing the casting process with the lowest cracking tendency for this alloy. For both Al-Cu alloys tested, the ZL201 alloy exhibits the lowest cracking tendency, with a minimum fracture grade of II.

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or modifications can be made to some or all of the technical solutions, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to 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, Including casting molds and electronically controlled induction devices; 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. The first direction and the second direction are perpendicular to each other. Each force measuring cavity includes two end sections arranged along the second direction and an intermediate constriction section connecting the two end sections. The cross-sectional area of ​​the intermediate constriction section is smaller than that of the end sections. The dimensions of the intermediate constriction sections of the plurality of force measuring cavities increase sequentially from top to bottom along the first direction. The electronically controlled sensing device includes a power module and multiple detection units connected in parallel with the power module. Each detection unit includes an indicator light and a detection wire with an insulating coating. The detection wire includes a detection section, which is located 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 corresponds one-to-one with the force measuring cavity.

2. The casting cracking tendency assessment device according to claim 1, characterized in that, The detection section of the detection lead includes a predetermined fracture section, which extends along a second direction, and the stress concentration area of ​​the intermediate contraction section is located within the area of ​​the predetermined fracture section.

3. The casting cracking tendency assessment device according to claim 1, characterized in that, The middle part of the casting mold is provided with multiple partition plates, and the area between the casting channel and the constriction channel is divided by the partition plates to form multiple force measuring cavities.

4. The casting cracking tendency assessment device according to claim 3, characterized in that, The detection wire section connected to the detection segment is partially embedded in the spacer plate at the corresponding force measuring cavity.

5. The casting cracking tendency assessment device according to claim 1, characterized in that, The top of the casting mold is provided with a pouring port and a vent. The pouring port is connected to the pouring channel, and the vent is connected to the constriction channel.

6. A method for assessing the tendency of casting to crack, characterized in that, The evaluation is performed using the casting cracking tendency evaluation apparatus according to any one of claims 1 to 5, comprising the following steps: Turn on the power module of the electronically controlled sensing device and confirm that all indicator lights are lit. Preheat the casting mold to the preset mold temperature; Molten metal is injected into the casting mold at a preset casting temperature, allowing the molten metal to flow into the casting channel, the constriction channel, and multiple force measuring chambers; During the solidification and cooling process of molten metal, the stress concentration state in the middle contraction section of each force measuring cavity is monitored in real time, specifically including: When the middle contraction section of a force measuring cavity breaks due to accumulated thermal stress, the corresponding detection wire is pulled off to extinguish the corresponding indicator light. By comparing and analyzing the number of indicator lights that go out when the middle contraction section of the force measuring cavity fractures under preset pouring temperature and preset mold temperature conditions for different alloy materials, the casting cracking tendency of the alloys can be evaluated.

7. The casting cracking tendency assessment method according to claim 6, characterized in that, Assessing the casting cracking susceptibility of an alloy specifically includes: The fracture level is determined by the number of indicator lights that are off. When the number of off indicator lights 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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