Alloy free solidification line shrinkage testing device

Abstract

The utility model discloses an alloy free solidification line shrinkage testing device which comprises a metal base, a T-shaped mold and a linear displacement sensor, the T-shaped mold and the linear displacement sensor are respectively arranged on the metal base, and an inner cavity of the T-shaped mold is integrally T-shaped and comprises a casting head, a cylindrical cavity and a horizontal rod cavity; a thermocouple is arranged on the T-shaped mold, and the thermocouple is positioned at the corner of the T-shaped mold; a graphite ring plug is arranged at the tail end of the horizontal rod; the end, away from the cylindrical cavity, of the horizontal rod is connected with the linear sensor through a cross-shaped connecting rod and a cross-shaped connecting rod. And the cross-shaped connecting rod and the cross-shaped connecting rod are connected through a bolt. The device is simple in structure, reasonable in design, convenient to operate and obvious in testing effect, and can be used for comparing the solidification line shrinkage of different alloys under the same casting condition or the solidification line shrinkage of the same alloy under different casting conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of physical property measurement in a metal solidification process, in particular to an alloy free solidification line shrinkage testing device. Background Art

[0002] Solidification shrinkage occurs during the solidification process of an alloy. As the solidification process progresses, the metal's volume changes. Combined with the restrictive effects of the mold structure, this creates solidification shrinkage stress within the alloy, leading to stress concentration in certain locations. In severe cases, this can cause hot cracking in the casting. Solidification line shrinkage of an alloy is an important indicator of the shrinkage strain or shrinkage stress generated during solidification. Generally speaking, the greater the solidification line shrinkage of an alloy, the greater the solidification shrinkage strain it will experience during solidification. When the alloy cannot accommodate this large solidification line shrinkage, hot cracking will occur. Therefore, accurately measuring solidification line shrinkage is crucial for evaluating and analyzing the alloy's casting properties, especially its hot cracking resistance.

[0003] In recent years, researchers have designed a number of test devices for testing the solidification line shrinkage of alloys. There are two common types of devices. One is a free solidification shrinkage test device. Its mold cavity is a simple rectangular parallelepiped, which cannot be well compared with samples that produce thermal cracking. In addition, during the test, the graphite ring and the connecting rod are fixed together, which increases the friction. The other type is a non-free solidification shrinkage test device. Its mold cavity is usually "T"-shaped, but during the test, there is no free solidification shrinkage. Cracks will occur during solidification. This test is usually used to analyze the process of thermal cracking during the solidification of alloys. However, as the free solidification line shrinkage of alloys is an important indicator for evaluating and analyzing the tendency of alloys to thermal cracking, it is necessary to design a free solidification line shrinkage test device for alloys in a thermal cracking test mold. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model aims to provide an alloy free solidification line shrinkage testing device.

[0005] The technical solution of the utility model is as follows: an alloy free solidification line shrinkage testing device, comprising a metal base and a "T"-shaped die and a linear displacement sensor respectively fixed on the metal base;

[0006] The internal cavity of the "T"-shaped mold is in a "T" shape as a whole, including a pouring riser, a cylindrical cavity and a horizontal rod cavity;

[0007] The "T"-shaped mold is provided with a thermocouple, and the position of the thermocouple is located at the corner of the "T"-shaped mold;

[0008] The end of the horizontal rod is provided with a graphite ring plug;

[0009] The horizontal rod is connected to the linear displacement sensor at one end away from the cylindrical cavity through a "+"-shaped connecting rod and a "-"-shaped connecting rod, and the "+"-shaped connecting rod and the "-"-shaped connecting rod are connected by bolts;

[0010] The horizontal rod cavity, the "+"-shaped connecting rod, the "-"-shaped connecting rod and the linear displacement sensor are located at the same horizontal height.

[0011] Preferably, the cylindrical cavity has a diameter of 40 mm and a height of 80 mm, the horizontal rod cavity has a diameter of 12.5 mm near the cylindrical cavity end, a diameter of 10 mm near the graphite ring plug end, and a length of 150 mm.

[0012] Preferably, the outer diameter of the graphite ring plug is 10.5-11 mm, and the inner diameter is 4-5 mm.

[0013] Preferably, the larger diameter portion of the "+"-shaped connecting rod has a diameter of 6 to 8 mm, and the smaller diameter portion has a diameter of 2 to 3 mm.

[0014] Preferably, the length of the smaller diameter portion on the left side of the "+"-shaped connecting rod is 5 to 10 mm, and the length of the larger diameter portion is 3 to 5 mm.

[0015] Preferably, the diameter of the “-”-shaped connecting rod is consistent with the diameter of the smaller diameter portion of the “+”-shaped connecting rod.

[0016] Preferably, the pouring nozzle is funnel-shaped.

[0017] Preferably, the thermocouple is provided with a stainless steel protective sleeve.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The mold of this utility model is a "T"-shaped mold commonly used in hot cracking tests. It can test the hot cracking behavior and free solidification line shrinkage of alloys under the same conditions, which can better combine the free solidification line shrinkage of alloys with hot cracking for analysis. It can also test the free solidification line shrinkage of different alloys or under different casting conditions. By comparing the free solidification line shrinkage of different alloys or under different casting conditions, the hot cracking tendency of the alloy can be predicted.

[0020] 2. The mold structure of the utility model is simple. Through the reasonable design of related structures such as the horizontal rod, graphite ring plug and connecting rod, the free solidification line shrinkage test of the alloy can be realized. It is easy to operate, has obvious test effect, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0022] Figure 1 Schematic diagram of the alloy free solidification line shrinkage test device of the present utility model

[0023] Figure 2 The connecting rod position is measured when the melt enters the mold cavity when the alloy free solidification line shrinkage test device of the utility model is used to test the melt.

[0024] Figure 3 It is the position of the connecting rod at the end of solidification when tested by the alloy free solidification line shrinkage testing device of the utility model.

[0025] Explanations in the figure: 1. Metal base; 2. Thermocouple; 3. Riser; 4. "T"-shaped mold; 5. Cylindrical cavity; 6. Horizontal rod cavity; 7. "+"-shaped connecting rod; 8. Graphite ring plug; 9. Bolt; 10. "-"-shaped connecting rod; 11. Linear displacement sensor; 12. Bracket. DETAILED DESCRIPTION

[0026] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural methods and implementation methods. Therefore, the following specific embodiments and drawings are only illustrative of the technical solution of the present invention and should not be regarded as the entire present invention or as a limitation or restriction of the technical solution of the present invention.

[0027] like Figure 1 As shown, as an alloy free solidification line shrinkage testing device of the present invention, it includes a metal base 1 and a "T"-shaped mold 4 and a linear displacement sensor 11 respectively arranged on the metal base 1. The height of the linear displacement sensor is adjusted by a bracket 12 fixed on the metal base 1.

[0028] Specifically, if Figure 1 As shown, the "T"-shaped mold 4 is provided with a pouring spout 3, and the internal cavity is "T"-shaped as a whole. The internal cavity of the "T"-shaped mold includes a cylindrical cavity 5 and a horizontal rod cavity 6, and the thermocouple 2 is located at the corner of the "T"-shaped mold 4.

[0029] The horizontal rod cavity 6 is provided with a graphite ring plug 8 at one end away from the cylindrical cavity 5. A "+"-shaped connecting rod 7 is passed inside the graphite ring plug 8. The "+"-shaped connecting rod 7 is connected to the "-"-shaped connecting rod 10 through a bolt 9. The "-"-shaped connecting rod 10 is connected to a linear displacement sensor 11. The linear displacement sensor 11 is connected to a computer through a signal collector to transmit displacement data during the solidification process.

[0030] The horizontal rod cavity 6, the “+”-shaped connecting rod 7, the “-”-shaped connecting rod and the linear displacement sensor 11 are located at the same level to ensure measurement accuracy.

[0031] During specific implementation, the pouring nozzle 3 is funnel-shaped.

[0032] In specific implementation, the cylindrical cavity 5 has a diameter of 40 mm and a height of 80 mm. The horizontal rod cavity 6 has a diameter of 12.5 mm near the end of the cylindrical cavity 5 and a diameter of 10 mm near the end of the graphite ring plug. The length is 150 mm. The diameter design of the horizontal rod cavity 6 can realize the free contraction of the alloy and avoid friction with the inner wall of the mold.

[0033] In a specific implementation, the thermocouple 2 is provided with a stainless steel protective sleeve, which can prevent the thermocouple 2 from being embedded in the casting and causing the thermocouple to be scrapped.

[0034] In a specific implementation, the outer diameter of the graphite ring plug 8 is 10.5-11 mm, and the inner diameter is 4-5 mm.

[0035] In specific implementation, the graphite ring plug 8 is fixed in the "T"-shaped mold 4 after the "T"-shaped mold 4 is assembled and will not move left or right, which can prevent the melt from entering the mold cavity and rushing the graphite ring plug 8 out of the mold.

[0036] In a specific implementation, the larger diameter of the "+"-shaped connecting rod 7 is 6 to 8 mm, and the smaller diameter of the "+"-shaped connecting rod 7 is 2 to 3 mm. In this way, the melt can be prevented from entering the gap between the "+"-shaped connecting rod 7 and the graphite ring plug 8 to cause shrinkage obstruction, and the influence of the gravity of the "+"-shaped connecting rod 7 itself can be reduced.

[0037] In specific implementation, the length of the smaller diameter portion on the left side of the "+"-shaped connecting rod 7 is 5-10 mm, and the length of the larger diameter portion is 3-5 mm, which can prevent the "+"-shaped connecting rod 7 from rubbing against the inner wall of the graphite ring plug 8.

[0038] In a specific implementation, the diameter of the “-”-shaped connecting rod 10 is consistent with the diameter of the smaller portion of the “+”-shaped connecting rod 7 , which can reduce the influence of the gravity of the “-”-shaped connecting rod 10 itself.

[0039] In a specific implementation, the accuracy of the linear displacement sensor 11 is not less than 0.001 mm, which can improve the accuracy of the test.

[0040] The present invention is Figure 1 The structural design of the horizontal rod cavity 6, the “+”-shaped connecting rod, the graphite ring plug 8 and the “-”-shaped connecting rod can achieve completely free contraction during the solidification process of the melt.

[0041] like Figure 2 As shown in the figure, upon entering the mold cavity, the melt in the horizontal rod cavity pushes the "+" connecting rod to the side of the graphite ring plug and wraps around it. After the melt solidifies, the "+" connecting rod and the alloy become one. As the alloy shrinks, the "+" connecting rod and the alloy move toward the cylindrical cavity until solidification is complete.

[0042] like Figure 3 As shown in the figure, after the alloy solidifies, the "+"-shaped connecting rod and the alloy move toward the cylindrical cavity for a distance. During the entire process, no melt enters the gap between the connecting rod and the graphite ring plug.

[0043] The solidification line shrinkage of Mg-xCa (x = 0.2, 0.5, 1 and 2, wt.%) was tested using the above-mentioned apparatus; the alloy was prepared and melted according to its nominal composition; after the melt reached the test temperature of 740°C, it was poured into the mold from the pouring riser 3 at a mold temperature of 250°C.

[0044] After the melt enters the T-shaped mold 4 cavity, it envelops the "+" connecting rod 7 and begins to solidify. After solidification shrinkage begins, the "+" connecting rod and the alloy move toward the cylindrical cavity 5 until solidification is complete. Finally, the data recorded by the computer is used to obtain the free solidification line shrinkage value of the alloy.

[0045] The results showed that the free solidification linear shrinkage values of Mg-0.2Ca, Mg-0.5Ca, Mg-1Ca and Mg-2Ca were 1.519mm, 1.574mm, 1.633mm and 1.526mm respectively.

[0046] Previous studies have shown that under the same casting conditions, Mg-0.2Ca and Mg-2Ca alloys have lower hot cracking tendency, while Mg-0.5Ca and Mg-1Ca alloys have higher hot cracking tendency.

[0047] From the results of the free solidification line shrinkage test, it can be concluded that the free solidification line shrinkage values of Mg-0.2Ca and Mg-2Ca are small, and the solidification shrinkage strain generated during the solidification process is small, so the hot cracking tendency is small. However, the free solidification line shrinkage values of Mg-0.5Ca and Mg-1Ca are large, and the solidification shrinkage strain generated during the solidification process is large. Therefore, the alloys are more likely to produce hot cracks due to the inability to coordinate the large solidification line shrinkage strain, and therefore have a greater hot cracking tendency.

[0048] The alloy free solidification line shrinkage value tested by the alloy free solidification line shrinkage testing device designed by the present invention well explains the hot cracking mechanism of different alloys under the same casting conditions.

[0049] The technical scope of the present invention is not limited to the contents described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical concept of the present invention, and these deformations and modifications should all fall within the scope of protection of the present invention.

Claims

1. An alloy free solidification line shrinkage testing device, characterized by: It includes a metal base, a "T"-shaped die and a linear displacement sensor respectively fixed on the metal base; The internal cavity of the "T"-shaped mold is in a "T" shape as a whole, including a pouring riser, a cylindrical cavity and a horizontal rod cavity; The "T"-shaped mold is provided with a thermocouple, and the position of the thermocouple is located at the corner of the "T"-shaped mold; The end of the horizontal rod is provided with a graphite ring plug; The horizontal rod is connected to the linear displacement sensor at one end away from the cylindrical cavity through a "+"-shaped connecting rod and a "-"-shaped connecting rod, and the "+"-shaped connecting rod and the "-"-shaped connecting rod are connected by bolts; The horizontal rod cavity, the "+"-shaped connecting rod, the "-"-shaped connecting rod and the linear displacement sensor are located at the same horizontal height.

2. The alloy free solidification line shrinkage testing device according to claim 1, characterized in that: The cylindrical cavity has a diameter of 40 mm and a height of 80 mm. The horizontal rod cavity has a diameter of 12.5 mm near the cylindrical cavity end and a diameter of 10 mm near the graphite ring plug end, and a length of 150 mm.

3. The alloy free solidification line shrinkage testing device according to claim 2, characterized in that: The outer diameter of the graphite ring plug is 10.5-11 mm, and the inner diameter is 4-5 mm.

4. The alloy free solidification line shrinkage testing device according to claim 3, characterized in that: The larger diameter portion of the "+"-shaped connecting rod has a diameter of 6 to 8 mm, and the smaller diameter portion has a diameter of 2 to 3 mm.

5. The alloy free solidification line shrinkage testing device according to claim 4, characterized in that: The length of the smaller diameter portion on the left side of the "+"-shaped connecting rod is 5 to 10 mm, and the length of the larger diameter portion is 3 to 5 mm.

6. The alloy free solidification line shrinkage testing device according to claim 1, characterized in that: The diameter of the "-"-shaped connecting rod is consistent with the diameter of the smaller diameter portion of the "+"-shaped connecting rod.

7. The alloy free solidification line shrinkage testing device according to claim 1, characterized in that: The pouring riser is funnel-shaped.

8. The alloy free solidification line shrinkage testing device according to claim 1, characterized in that: The thermocouple is provided with a stainless steel protection sleeve.

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