Insert for accurately measuring temperature of multiple positions in squeeze casting mold and temperature measuring method

Abstract

The invention discloses an insert for accurately measuring the temperature of multiple positions in an extrusion casting mold and a temperature measuring method, the insert for accurately measuring the temperature of the multiple positions in the extrusion casting mold comprises a temperature measuring main body mounted in the mold, and one surface, in contact with a casting, of the temperature measuring main body is a temperature measuring surface; a plurality of groups of temperature measuring holes are formed in the temperature measuring main body, each group of temperature measuring holes comprises a through hole and a blind hole which extend to the temperature measuring surface, and thermocouples are arranged in the through holes and the blind holes. According to the invention, the multiple groups of temperature measuring holes comprising the through holes and the blind holes are formed in the temperature measuring main body, so that the purpose of simultaneously measuring the melt temperature and the mold temperature at different positions in the casting process is achieved, and dual temperature monitoring is provided for the casting process.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature measurement of extrusion casting molds, and in particular relates to an insert and a temperature measurement method for accurately measuring the temperature at multiple positions inside an extrusion casting mold. Background Art

[0002] Nowadays, the automotive industry is developing rapidly, and extremely high requirements are put forward for lightweight automobiles. High-performance aluminum alloys are increasingly used in automotive parts. The common production process of aluminum alloys is extrusion casting. The characteristics of the extrusion casting (also known as liquid forging) process are that the casting has good contact with the mold and the melt is solidified under pressure. Therefore, the solidification and cooling rate of the casting is fast, the grains are fine, the casting is dense inside, and it has a low tendency of shrinkage and shrinkage.

[0003] Computer simulation technology is widely used in extrusion casting, which can greatly shorten the R&D cycle and improve the product qualification rate. In the simulation technology of extrusion casting, the interface heat transfer coefficient between the melt and the mold is an extremely important key parameter, and its accuracy seriously affects the accuracy of the simulation results. The interface heat transfer coefficient h is defined as: Where q is the interface heat flux, A is the interface area, T C is the casting interface temperature, T M is the mold interface temperature.

[0004] The inverse algorithm is the most commonly used method for solving the heat transfer coefficient of the casting-mold interface. The core idea of ​​the inverse algorithm is to solve the unknown boundary, internal heat source or initial condition by directly solving the linear problem or iteratively solving the nonlinear problem according to the measurement results of the internal temperature. In summary, the basic concept of the inverse algorithm for solving the interface heat transfer coefficient is: assuming that the heat flux value of the mold cavity surface is constant within a certain time interval, and arbitrarily giving an initial value, that is, the mold temperature field, to obtain the calculated temperature values ​​at all positions and all times during this period of time, and by minimizing the sum of the squares of the differences between all measured temperatures and calculated temperatures during this period of time, the actual heat flow value during this period of time is obtained, and then the casting and mold surface temperatures are calculated to obtain the casting-mold interface heat transfer coefficient. Therefore, how to accurately measure the temperature at different positions in the mold has become the key to accurately calculating the casting-mold interface heat transfer coefficient.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide an insert and a temperature measurement method for accurately measuring the temperature at multiple positions inside an extrusion casting mold. The insert is installed in the mold and can simultaneously measure the temperature of different positions and thicknesses of the casting, and can measure the temperature at different positions of the mold with accurate temperature measurement.

[0007] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0008] An insert for accurate temperature measurement at multiple positions inside an extrusion casting mold, comprising a temperature measuring body for installation in the mold, wherein a side of the temperature measuring body contacting the casting is a temperature measuring surface;

[0009] A plurality of groups of temperature measuring holes are arranged in the temperature measuring body, each group of the temperature measuring holes comprises a through hole and a blind hole extending to the temperature measuring surface, and thermocouples are arranged in the through hole and the blind hole.

[0010] In one or more embodiments of the present invention, the distance between the bottom of the blind hole and the temperature measuring surface is 2 to 10 mm.

[0011] In one or more embodiments of the present invention, each group of temperature measuring holes includes one through hole and two blind holes.

[0012] In one or more embodiments of the present invention, the distance between the blind hole and the through hole is 4-8 mm.

[0013] In one or more embodiments of the present invention, when the thermocouple is located in the temperature measuring hole, the distance between the thermocouple and the inner surface of the temperature measuring hole is less than ±0.04; and / or, high temperature glue is used to fill the gap between the through hole and the thermocouple.

[0014] In one or more embodiments of the present invention, the thermocouple is a needle-type armored thermocouple; and / or the temperature measuring body is made of H13 hot working die steel.

[0015] In one or more embodiments of the present invention, the end of the thermocouple is threadedly connected to the temperature measuring body.

[0016] In one or more embodiments of the present invention, the thermocouple is provided with a nut located outside the temperature measuring body, and the nuts on adjacent thermocouples are staggered.

[0017] In one or more embodiments of the present invention, the temperature measuring body includes a first body and a second body cooperating with the first body, the first body is provided with a first positioning groove for cooperating with the mold, and the second body is provided with a second positioning groove for cooperating with the mold.

[0018] Another specific embodiment of the present invention provides a technical solution as follows:

[0019] A method for accurately measuring temperature at multiple positions inside an extrusion casting mold comprises the following steps:

[0020] The insert is mounted on the fixed mold of the mold so that the temperature measuring surface of the temperature measuring body constitutes the inner surface of the cavity;

[0021] Connect the thermocouple wires to the multi-channel data logger;

[0022] The extrusion casting of the casting between the movable mold and the fixed mold is carried out, and the temperature measurement data of each casting cycle is measured and recorded by the data acquisition system.

[0023] Compared with the prior art, the insert in the present invention can adapt to different molds, maintaining a high degree of flexibility and economy. The design of the through holes and blind holes in the insert enables the thermocouple to directly and accurately measure the temperature of the melt during the solidification process, while also being able to monitor the mold temperature, providing dual temperature monitoring for the casting process.

[0024] In addition, the threaded connection between the thermocouple and the temperature measuring body ensures that the temperature measuring end of the thermocouple can be accurately aligned with the mold surface, so that the thermocouple can maintain stability during the casting process, thereby improving the measurement accuracy.

[0025] Since the thermocouple is independently set in the temperature measuring body, after the temperature measurement is completed, the entire insert can be replaced with a solid insert without holes and thermocouples, so as to reduce the potential impact on the life of the mold and enable the mold to maintain its integrity and performance during multiple uses. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of an insert for accurate temperature measurement at multiple positions inside an extrusion casting mold in one embodiment of the present invention;

[0028] Figure 2 A cross-sectional view of an insert for accurate temperature measurement at multiple positions inside an extrusion casting mold in one embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the structure in which the insert for accurate temperature measurement at multiple positions inside the extrusion casting mold is installed in the mold in one embodiment of the present invention Figure 1 ;

[0030] Figure 4 Schematic diagram of the structure in which the insert for accurate temperature measurement at multiple positions inside the extrusion casting mold is installed in the mold in one embodiment of the present invention Figure 2 .

[0031] Description of main reference numerals:

[0032] 1. Temperature measuring body; 10. Temperature measuring surface; 11. First body; 12. Second body; 111. Threaded groove; 112. First positioning groove; 121. Second positioning groove; 2. Temperature measuring hole; 21. Through hole; 22. Blind hole; 3. Thermocouple; 31. Hexagonal nut; 4. Fixed mold; 5. Moving mold; 6. Bolt. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0034] like Figure 1 As shown, a specific embodiment of the present invention provides an insert for accurate temperature measurement at multiple positions inside an extrusion casting mold, which includes a temperature measuring body 1, which is used to be installed in a fixed mold 4 to form a cavity, and the surface of the temperature measuring body 1 in contact with the casting is a temperature measuring surface 10. In other embodiments, the temperature measuring body 1 can also be installed in a movable mold 5 to form a core.

[0035] The temperature measuring body 1 includes a first body 11 and a second body 12 in a square shape. The first body 11 and the second body 12 are both provided with a threaded groove 111 to be connected to the fixed mold 4 by bolts. In order to improve the accuracy of installation, the first body 11 is provided with a first positioning groove 112, and the second body 12 is provided with a second positioning groove 121. The fixed mold 4 can be provided with a convex block embedded in the first positioning groove 112 and the second positioning groove 121 to achieve the purpose of positioning the temperature measuring body 1 and realize accurate installation. It should be noted that the specific shapes of the first body 11 and the second body 12 are not limited to square, but can also be cylindrical.

[0036] Combination Figure 2Four groups of temperature measuring holes 2 are arranged in the temperature measuring body 1 along the length direction of the temperature measuring surface 10. Each group of temperature measuring holes 2 includes a through hole 21 and two blind holes 22. The through hole 21 and the blind hole 22 are provided with thermocouples 3. The through hole 21 passes through the temperature measuring surface 10 so that the temperature measuring end of the thermocouple 3 directly contacts the casting for temperature measurement. The two blind holes 22 are respectively located on both sides of the through hole 21 so that the thermocouple 3 in the blind hole 22 measures the mold temperature. In actual extrusion casting, the thickness of the casting is different at different positions. By setting four groups of temperature measuring holes 2, the temperature of the casting at different positions and thicknesses can be measured, thereby measuring the temperature change under different cooling rates. At the same time, the temperature of the mold at different positions can also be measured.

[0037] In order to better measure the casting temperature and mold temperature at different positions, the spacing between the inner bottom of the blind hole 22 and the temperature measuring surface 10 is 2 to 10 mm. Specifically, in the two blind holes 22 of each group of temperature measuring holes 2, the spacing between the inner bottom of one blind hole 22 and the temperature measuring surface 10 is twice the spacing between the inner bottom of the other blind hole 22 and the temperature measuring surface 10. For example, in the present specific embodiment, the spacing between the inner bottom of one blind hole 22 and the temperature measuring surface 10 is 10 mm, and the spacing between the inner bottom of the other blind hole 22 and the temperature measuring surface 10 is 5 mm. Of course, the spacing between the inner bottom of one blind hole 22 and the temperature measuring surface 10 can also be set to 8 mm, and the spacing between the inner bottom of the other blind hole 22 and the temperature measuring surface 10 can be set to 4 mm.

[0038] Furthermore, in each group of temperature measuring holes 2, the spacing between the blind hole 22 and the through hole 21 is 4 to 8 mm. Specifically, the spacing between the blind hole 22 and the through hole 21 can be set to 4 mm, 6 mm or 8 mm. In the present specific embodiment, the spacing between the blind hole 22 and the through hole 21 is 6 mm.

[0039] In order to improve the measurement accuracy, the thermocouple 3 is a needle-type armored thermocouple, and the internal process of the probe adopts a shell-connected type, which ensures that it has a high temperature measurement sensitivity. The diameter of the thermocouple 3 is 1mm, the inner diameters of the blind hole 22 and the through hole 21 are both 1mm, and when the thermocouple 3 is installed in the temperature measuring hole 2, the spacing between the thermocouple 3 and the inner surface of the temperature measuring hole 2 is less than ±0.04mm to ensure that the thermocouple 3 and the inner surface of the temperature measuring hole 2 are effectively abutted. The diameter of the thermocouple 3 will affect the temperature measurement sensitivity and its own performance. The thicker the diameter, the higher the temperature hysteresis. The thinner the diameter, the worse the stiffness of the thermocouple 3, which is not conducive to installation. Therefore, the present invention selects a thermocouple 3 with a diameter of 1mm to ensure the installation effect and the temperature measurement effect at the same time. After the thermocouple 3 is installed in the through hole 21, a high-temperature glue is used to seal the gap between the thermocouple 3 and the through hole 21 to prevent the melt from penetrating.

[0040] The inner surface of the blind hole 22 is provided with a thread at the orifice, and the inner surface of the through hole 21 is also provided with a thread at the orifice, and the end of the thermocouple 3 is threadedly connected to the temperature measuring body 1. Through the threaded connection, it can be ensured that the end face of the thermocouple 3 is in close contact with the inner bottom of the blind hole 22, and the end face of the thermocouple 3 is flush with the orifice of the through hole 21, so as to improve the accuracy of temperature measurement. In addition, the threaded connection can also avoid the situation where the pressure during the melt pressurization causes the thermocouple 3 to retreat into the through hole 21, and it can ensure that the end face of the thermocouple 3 is in close contact with the surface of the casting. Hexagonal nuts 31 are provided on the thermocouples 3, and the hexagonal nuts 31 on adjacent thermocouples 3 are staggered to ensure that the hexagonal nuts 31 do not interfere with each other during the tightening process.

[0041] Another specific embodiment of the present invention provides a method for accurately measuring the temperature at multiple positions inside an extrusion casting mold, comprising the following steps:

[0042] First, the insert for accurate temperature measurement at multiple positions inside the extrusion casting mold is installed on the fixed mold 4 by using bolts 6. Figure 3 and Figure 4 As shown, the temperature measuring surface 10 of the temperature measuring body 1 constitutes the inner surface of the cavity;

[0043] Then connect the wire of thermocouple 3 to the multi-channel data recorder;

[0044] The extrusion casting of the casting between the movable mold 5 and the fixed mold 4 is carried out, and the temperature measurement data of each casting cycle is measured and recorded by a multi-channel data recorder.

[0045] In addition, after the temperature measurement is completed, the insert can be replaced with an unperforated insert to reduce the impact of the punching on the mold life, thereby reducing costs.

[0046] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An insert for accurate temperature measurement at multiple positions inside an extrusion casting mold, characterized in that: It includes a temperature measuring body for installation in the mold, wherein a side of the temperature measuring body contacting the casting is a temperature measuring surface; A plurality of groups of temperature measuring holes are arranged in the temperature measuring body, each group of the temperature measuring holes comprises a through hole and a blind hole extending to the temperature measuring surface, and thermocouples are arranged in the through hole and the blind hole.

2. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: The distance between the bottom of the blind hole and the temperature measuring surface is 2 to 10 mm.

3. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: Each group of temperature measuring holes includes one through hole and two blind holes.

4. The insert for accurate temperature measurement at multiple positions inside the extrusion casting mold according to claim 3, characterized in that: The distance between the blind hole and the through hole is 4-8 mm.

5. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: When the thermocouple is located in the temperature measuring hole, the distance between the thermocouple and the inner surface of the temperature measuring hole is less than ±0.04 mm; and / or, high temperature glue is used to fill the gap between the through hole and the thermocouple.

6. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: The thermocouple is a needle-type armored thermocouple; and / or the temperature measuring body is made of H13 hot working die steel.

7. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: The end of the thermocouple is threadedly connected to the temperature measuring body.

8. The insert for accurate temperature measurement at multiple positions inside the extrusion casting mold according to claim 7, characterized in that: The thermocouple is provided with a nut located outside the temperature measuring body, and the nuts on adjacent thermocouples are staggered.

9. The insert for accurate temperature measurement at multiple positions inside the squeeze casting mold according to claim 1, characterized in that: The temperature measuring body comprises a first body and a second body matched with the first body, the first body is provided with a first positioning groove for matching with the mold, and the second body is provided with a second positioning groove for matching with the mold.

10. A method for accurate temperature measurement at multiple positions inside an extrusion casting mold, characterized in that: The steps include: The insert according to any one of claims 1 to 9 is mounted on a fixed mold of a mold, so that the temperature measuring surface of the temperature measuring body constitutes the inner surface of the cavity; Connect the thermocouple wires to the multi-channel data logger; The extrusion casting of the casting between the movable mold and the fixed mold is carried out, and the temperature measurement data of each casting cycle is measured and recorded by the data acquisition system.

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