CN111220648B - Method for measuring interface heat exchange coefficient of aluminum alloy hot stamping process - Google Patents
Method for measuring interface heat exchange coefficient of aluminum alloy hot stamping process Download PDFInfo
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Abstract
The invention provides a method for measuring an interface heat exchange coefficient of an aluminum alloy hot stamping process, which comprises the following steps of: measuring the surface roughness of an experimental mould and a sample; collecting the temperatures of an experimental die and a sample at intervals of unit time t in the hot stamping experimental process; outputting a temperature-time curve of the sample in the experimental process, and calculating a pre-estimated interface heat exchange coefficient; establishing a micro-scale finite element simulation model according to the measured surface roughness; inputting a predicted interface heat exchange coefficient to perform finite element simulation analysis; outputting a temperature-time curve of the sample in the finite element simulation process; and comparing whether the sample temperature-time curve in the simulation process is consistent with the sample temperature-time curve in the experimental process, if so, outputting the estimated interface heat exchange coefficient as a final result, and if not, correcting the estimated interface heat exchange coefficient and analyzing again. The method can eliminate the influence of the surface roughness on the measurement result and improve the measurement precision of the interface heat exchange coefficient in the hot stamping process.
Description
Technical Field
The invention relates to the field of metal plastic forming, in particular to a method for measuring an interface heat exchange coefficient of an aluminum alloy hot stamping process.
Background
The interface heat exchange coefficient is an important process parameter in the aluminum alloy hot stamping process, reflects the heat exchange capacity between a die and a sample, and has important influence on the simulation result of a finite element model. The interface heat exchange coefficient experiment of the conventional aluminum alloy hot stamping process adopts the following method: and measuring the change curves of the temperature inside the die and the temperature of the sample in the stamping process by using a thermocouple, and calculating the theoretical value of the interface heat exchange coefficient by using a difference value calculation method. In a real environment, the surface roughness of the sample has a remarkable influence on the interface heat exchange efficiency; in the finite element model, the influence of the surface roughness is usually not considered, so that the interface coefficient obtained by the experiment is used for simulation in the finite element simulation, and a certain difference exists between the simulation result and the experiment result.
In order to further improve the accuracy of finite element simulation, a more reasonable method for measuring the heat transfer coefficient needs to be provided to reduce the influence of surface roughness on the measurement of the heat transfer coefficient. Therefore, the invention combines the interface heat exchange coefficient experiment of the conventional aluminum alloy hot stamping process with finite element simulation, utilizes the surface roughness to simulate the plastic deformation of the uneven surface of the sample in the stamping process, and more truly reflects the change of the interface between the die and the plate in the aluminum alloy hot stamping process, thereby eliminating the influence of the surface roughness on the measurement result and improving the measurement precision of the interface heat exchange coefficient in the aluminum alloy hot stamping process.
Disclosure of Invention
In view of the above, the present invention is directed to a method for measuring an interface heat transfer coefficient in an aluminum alloy hot stamping process, so as to eliminate the influence of surface roughness on a measurement result.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for measuring the heat exchange coefficient of an interface of an aluminum alloy hot stamping process comprises the following steps:
step 1: assembling an experimental device and measuring the surface roughness of an experimental mould and a sample;
step 2: carrying out a hot stamping experiment, and collecting the temperatures of the experimental die and the sample at intervals of unit time t in the hot stamping experiment process;
and step 3: outputting a temperature-time curve of the sample in the experimental process, and calculating a pre-estimated interface heat exchange coefficient;
and 4, step 4: establishing a micro-scale finite element simulation model according to the surface roughness of the experimental mould and the sample;
and 5: inputting a predicted interface heat exchange coefficient to perform finite element simulation analysis;
step 6: outputting a temperature-time curve of the sample in the finite element simulation process;
and 7: and (5) comparing whether the sample temperature-time curve in the simulation process is consistent with the sample temperature-time curve in the experimental process, if so, outputting the estimated interface heat exchange coefficient as a final result, and if not, correcting the estimated interface heat exchange coefficient and returning to the step 5.
Further, in the step 4, a specific method for establishing a micro-scale finite element simulation model according to the surface roughness of the experimental mold and the sample comprises the following steps:
step 41: according to the surface roughness of the experimental mold and the sample, the surface of the sample, which is in contact with the experimental mold, is in a curved surface shape with wave crests and wave troughs;
step 42: the experimental mould is designed to be a rigid body, and does not deform in the stamping process;
step 43: designing the sample as an elastic plastic body, wherein the sample can be subjected to plastic deformation in the stamping process;
step 44: and setting the simulation model of the sample by adopting a grid repartitioning function.
Further, the finite element simulation model is a two-dimensional section model. The design of the finite element model only needs to consider the section part of the sample in the vertical rolling direction, and the two-dimensional section model is adopted, so that the finite element simulation analysis is simpler, and the analysis time is shortened.
Further, the surface of the test sample, which is in contact with the experimental mold, is a curved surface shape with wave crests and wave troughs, and the curved surface shape is drawn by adopting a spline curve. In the method, the shape of the curved surface is a curve shape after being projected in a direction vertical to the paper surface, and the spline curve is adopted for drawing, so that the modeling method is simple and rapid.
Further, the dimension of the sample in the width direction is 100 to 2000. mu.m. Since the surface roughness is on the order of μm in size, the dimensional range of the overall profile of the test specimen and the experimental mold should not be too large.
Furthermore, when the sample is subjected to the mesh repartitioning function setting, the unilateral length of the mesh is not more than 0.6 μm. As the surface roughness Ra of the sample is 0.8-6.4 μm in general, the divided meshes are smaller as much as possible, and the accuracy of finite element simulation analysis is ensured.
Furthermore, in the step 2, a plurality of thermocouples for collecting the temperature are horizontally arranged on the experiment mould and the sample, and the thermocouples are connected with a temperature collection module.
Further, the specific method for comparing whether the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experiment process in the step 7 is as follows:
step 71: calculating the average cooling rate of the sample during the experiment;
step 72: calculating the average cooling rate of the sample in the simulation process;
step 73: and comparing whether the deviation between the average cooling rate of the sample in the simulation process and the average cooling rate of the sample in the experiment process is less than or equal to 10%, if so, judging that the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experiment process, and if not, judging that the temperature-time curves are inconsistent.
Further, the specific method for correcting the estimated interface heat transfer coefficient in step 7 is as follows: reducing the estimated interface heat exchange coefficient if the average cooling rate of the sample in the simulation process is greater than the average cooling rate of the sample in the experiment process; and if the average cooling rate of the sample in the simulation process is smaller than the average cooling rate of the sample in the experiment process, the estimated interface heat exchange coefficient is increased.
Furthermore, the value of the unit time t is 0.02s, and the value of the t needs to be acquired for enough times due to the short stamping process so as to ensure the accuracy of subsequent numerical value calculation.
The method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process has the following advantages:
(1) according to the method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process, the roughness of the surface of the simulation sample can be compressed and deformed in the simulation process, so that the change of the interface between a die and a plate in the aluminum alloy hot stamping process can be reflected more truly, the influence of the surface roughness on the heat exchange coefficient measurement result is eliminated, and the method has important significance for improving the accuracy of finite element simulation of the aluminum alloy hot stamping process;
(2) the method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process can be applied to other hot forming processing processes needing to measure the interface heat exchange coefficient.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram illustrating the steps of a method for measuring the heat transfer coefficient of an interface according to an embodiment of the present invention;
FIG. 2 is a flowchart illustrating a method for measuring the heat transfer coefficient of an interface according to an embodiment of the present invention;
FIG. 3 is a schematic view of an experimental apparatus for measuring the interface heat transfer coefficient according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a conventional model of an experimental mold and a sample according to an embodiment of the present invention;
fig. 5 is a schematic view of a micro-scale model of an experimental mold and a sample according to an embodiment of the present invention.
Description of reference numerals:
1. the device comprises an upper die, a sample, a positioning pin, a lower die, a first thermocouple, a second thermocouple, a third thermocouple, a fourth thermocouple, a fifth thermocouple, a second thermocouple, a third thermocouple, a fourth.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The descriptions in this document referring to "first", "second", "upper", "lower", etc. are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," "upper," "lower," may explicitly or implicitly include at least one of the feature. In addition, the technical solutions in the embodiments may be combined with each other, but it is necessary that a person skilled in the art can realize the combination, and the technical solutions in the embodiments are within the protection scope of the present invention.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
As shown in FIG. 1, a method for measuring the heat transfer coefficient of an interface in an aluminum alloy hot stamping process comprises the following steps:
step 1: assembling an experimental device and measuring the surface roughness of an experimental mould and a sample;
step 2: carrying out a hot stamping experiment, and collecting the temperatures of the experimental die and the sample at intervals of unit time t in the hot stamping experiment process;
and step 3: outputting a temperature-time curve of the sample in the experimental process, and calculating a pre-estimated interface heat exchange coefficient;
and 4, step 4: establishing a micro-scale finite element simulation model according to the surface roughness of the experimental mould and the sample;
and 5: inputting a predicted interface heat exchange coefficient to perform finite element simulation analysis;
step 6: outputting a temperature-time curve of the sample in the finite element simulation process;
and 7: and (5) comparing whether the sample temperature-time curve in the simulation process is consistent with the sample temperature-time curve in the experimental process, if so, outputting the estimated interface heat exchange coefficient as a final result, and if not, correcting the estimated interface heat exchange coefficient and returning to the step 5.
The value of the unit time t is a value larger than 0 and is in units of seconds, preferably, the value of t is 0.02 seconds, namely sampling is carried out 50 times per second, and the temperature value can be acquired as much as possible and the accuracy of the whole measurement result can be ensured because the hot stamping process is short and the value of the unit time t is a small value.
Furthermore, in step 2, the experiment mould with the sample is improved level and is provided with a plurality of thermocouples that carry out the collection to the temperature, the thermocouple is connected with the temperature acquisition module, and the thermocouple level sets up, can guarantee that the temperature value of gathering is more accurate.
Preferably, in the whole experiment process, the temperatures of the plate and the die are collected by a K-type thermocouple, and a data acquisition card is used for recording in a temperature acquisition module.
Further, in the step 4, the specific method for establishing the hot stamping microscale finite element simulation model according to the surface roughness of the experimental mold and the sample comprises the following steps:
step 41: according to the surface roughness of the experimental mold and the sample, the surface of the sample, which is in contact with the experimental mold, is in a curved surface shape with wave crests and wave troughs;
step 42: the experimental mould is designed to be a rigid body, and does not deform in the stamping process;
step 43: designing the sample as an elastic plastic body, wherein the sample can be subjected to plastic deformation in the stamping process;
step 44: and setting the simulation model of the sample by adopting a grid repartitioning function.
To take the influence of the surface roughness into consideration, the finite element analysis herein is designed not to design the contact surface of the experimental mold and the test piece to be a plane, as in the conventional model in fig. 4, but to design the experimental mold and the test piece to have a curved surface of peaks and valleys, as shown in fig. 5, in order to simulate the surface roughness at a microscopic scale.
Preferably, the samples used in the hot stamping experiment are rolled plates, the rolled plates have obvious lines along the rolling direction, and the roughness introduced by the lines accounts for the main part of the roughness of the samples. Therefore, the finite element model is designed only by considering the section part of the sample in the vertical rolling direction and performing simulation analysis by using the two-dimensional section model.
More preferably, the shapes of the experimental mould and the sample are designed by using CAD software, and the shape of the surface roughness is drawn by adopting a spline curve. For example, when the surface roughness Ra of the sample is 1.6 μm, the upper surface of the sample is first drawn as a plane, then the upper surface is shifted by 0.8 μm upward and downward, and the upper and lower shift lines are sequentially clicked using a spline curve, thereby finally generating the surface roughness shape of the sample, and the surface roughness shape of the experimental mold is similarly drawn.
More preferably, in consideration of the symmetry of the upper die and the lower die in the contact heat exchange process, only the contact between the upper die and the upper surface of the sample is simulated in the finite element simulation process, and the thickness of the sample model is half of the actual thickness.
It should be noted that, since the dimension of the surface roughness is on the order of μm, the dimension range of the entire outer shape of the sample and the experimental mold should not be excessively large, the dimension of the sample in the width direction is 100 μm to 2000 μm, and when the surface roughness Ra of the sample is 1.6 μm, the width of the sample is 500 to 1000 μm, preferably 800 μm, and it is convenient for grid division and calculation. And (4) importing the drawn CAD model into a finite element model, and setting corresponding model parameters, which is similar to a conventional analysis method. The difference is that because the surface roughness effect is considered, the wave crest on the surface of the sample can deform in the contact process with the experimental mold, and the subdivision function of the sample grid needs to be introduced into the model setting so as to enable the grid to adapt to the large deformation in the contact process. Meanwhile, the size of the grid needs to be refined as much as possible, the length of the single side of the grid is not more than 0.6 μm, and when Ra is 1.6 μm, the length of the single side of the grid can be set to be not more than 0.16 μm, preferably 0.16 μm, so that the analysis and calculation are convenient.
In a real experiment, a peak of roughness can be flattened in the stamping process, so that the heat exchange coefficient of an interface changes, therefore, the simulation model simulates the roughness of the surface of a sample, the peak of the roughness can be compressed and deformed, the change of the interface between a die and a plate in the hot stamping process of the aluminum alloy is reflected more truly, and the influence of the surface roughness on the measurement result of the heat exchange coefficient is eliminated.
Further, in the step 5, the estimated interface heat exchange coefficient is calculated by the temperatures of the experimental mold and the sample.
The calculation of the estimated interface heat transfer coefficient can adopt a formula:
hw＝CbρbV/S·(dTb/dt)/(Tb-T0)
in the formula, hwIs the heat transfer coefficient in the unit W/(m 2. K), CbAnd ρbRespectively, the specific heat capacity and density of the sample material, V is the sample volume, S is the contact area between the sample and the experimental mold, dTbDt is the cooling rate of the sample, TbAnd TdShowing sample and experimental mould respectivelySurface temperature, TbAnd TdThe value of (b) is obtained by conversion according to the collected sample and the internal temperature of the experimental mold, and the calculation method is the prior art and is not repeated herein.
Further, the specific method for comparing whether the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experiment process in the step 7 is as follows:
step 71: calculating the average cooling rate of the sample during the experiment;
step 72: calculating the average cooling rate of the sample in the simulation process;
step 73: and comparing whether the deviation between the average cooling rate of the sample in the simulation process and the average cooling rate of the sample in the experiment process is less than or equal to 10%, if so, judging that the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experiment process, and if not, judging that the temperature-time curves are inconsistent.
Setting the temperature of the sample in the experimental process at the moment T of the first unit time as T1And the temperature of the sample at the second time point of 2T per unit time is T2And the temperature of the sample at the nth unit time T x n is TnWhere n is an integer greater than 0, the average cooling rate of the sample during the experiment
Setting the temperature of the sample in the simulation process at the moment T of the first unit time to be T1', the sample temperature at the second time point of unit time 2T is T2', the sample temperature at the nth unit time T x n is Tn' average cooling rate of the sample during the experiment
The average cooling rate of the sample deviates from the average cooling rate of the sample during the experiment by P, where P ═ VImitation-VFruit of Chinese wolfberry|/VFruit of Chinese wolfberryValue of PIs less than or equal to 10%.
Further, the specific method for correcting the estimated interface heat transfer coefficient in step 7 is as follows: reducing the estimated interface heat exchange coefficient if the average cooling rate of the sample in the simulation process is greater than the average cooling rate of the sample in the experiment process; and if the average cooling rate of the sample in the simulation process is smaller than the average cooling rate of the sample in the experiment process, the estimated interface heat exchange coefficient is increased.
As shown in fig. 3, which is a schematic structural diagram of an experimental device, the experimental device includes an upper die 1, a sample 2, a positioning pin 3, a lower die 4, a first thermocouple 5, a second thermocouple 6, a third thermocouple 7, a fourth thermocouple 8, and a fifth thermocouple 9, the sample 2 is mounted on the lower die 4, the positioning pin 3 is mounted on the edge of the lower die 4, a plurality of positioning pins 3 are provided to position the sample 2, the upper die 1 can move downward to perform hot stamping on the sample 2, preferably, the surfaces of the upper die 1 and the lower die 4 contacting the sample 2 are planes, the structure is simple, the hot stamping experiment is convenient, the experimental cost is saved, two holes with the diameter of 1mm are processed on the upper die 1, the central line of the hole is parallel to the surface of the upper die 1 contacting the sample 2, and is respectively 1mm and 2mm from the surface of the die, the depth of the hole is from the cylindrical outer, the diameters of the first thermocouple 5 and the second thermocouple 6 are both 1mm, the first thermocouple and the second thermocouple are respectively arranged in the two holes, and the end parts of the thermocouples are abutted against the bottoms of the holes; two holes with the diameter of 1mm are processed on the lower die 4, the central lines of the holes are parallel to the surface of the upper die 1, which is in contact with the sample 2, and are respectively 1mm and 2mm away from the surface of the die, the depth of the holes is from the cylindrical outer surface of the lower die 4 to the axial symmetry line, the diameters of the fourth thermocouple 8 and the fifth thermocouple 9 are both 1mm, the fourth thermocouple and the fifth thermocouple are respectively arranged in the two holes, and the end parts of the thermocouples are abutted against the bottoms of the holes; in the middle position of the thickness of a plate material of a sample 2, a hole with the diameter of 1mm is machined, the depth of the hole is from the cylindrical outer surface of the sample 2 to an axial symmetry line, a third thermocouple 7 is inserted into the hole, the end part of the thermocouple is abutted to the bottom of the hole, the diameter of the third thermocouple is 1mm, the first thermocouple 5 and the second thermocouple 6 respectively measure the temperature of the positions of the first thermocouple and the second thermocouple and convert the temperature into the surface temperature of an upper die 1, the third thermocouple 7 measures the temperature of the sample 2, the fourth thermocouple 8 and the fifth thermocouple 9 respectively measure the temperature of the positions of the first thermocouple and the second thermocouple and convert the temperature into the surface temperature of a lower die 4, and as the surface temperatures of the upper die 1 and the lower die 4 are theoretically the same, the average value of the surface temperatures of the upper die 1 and the.
As shown in fig. 2, a flow chart of a specific method for measuring an interface heat transfer coefficient of an aluminum alloy hot stamping process is provided, which includes assembling an experimental device, measuring surface roughness of an experimental mold and a sample, performing a hot stamping experiment, collecting temperatures of the mold and the sample per unit time t in the experimental process, outputting a temperature-time curve of the sample in the experimental process, calculating an estimated interface heat transfer coefficient according to temperature values of the collected mold and the sample, and calculating an average cooling rate of the sample in the experimental process according to the temperature-time curve of the sample in the experimental process; secondly, establishing a micro-scale finite element simulation model according to the surface roughness of the experiment mould and the sample, designing the experiment mould as a rigid body and the sample as an elastic plastic body, simulating the surface roughness distribution of the experiment mould and the sample by adopting a random finite element model, inputting the estimated interface heat exchange coefficient to perform finite element simulation analysis, outputting a temperature-time curve of the sample in the finite element simulation process, and calculating the average cooling rate of the sample in the simulation process according to the temperature-time curve; comparing whether the deviation of the average cooling rate of the sample in the simulation process with the average cooling rate of the sample in the experiment process is less than or equal to 10%, if so, judging that the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experiment process, outputting the estimated interface heat exchange coefficient as a final interface heat exchange coefficient, if the deviation of the average cooling rate of the sample in the simulation process with the average cooling rate of the sample in the experiment process is more than 10%, judging that the temperature-time curve of the sample in the simulation process is inconsistent with the temperature-time curve of the sample in the experiment process, further judging, if the average cooling rate of the sample in the simulation process is more than the average cooling rate of the sample in the experiment process, reducing the estimated interface heat exchange coefficient, and (3) carrying out finite element simulation analysis again, if the average cooling rate of the sample in the simulation process is less than the average cooling rate of the sample in the experiment process, increasing the estimated interface heat exchange coefficient, and carrying out finite element simulation analysis again until the deviation between the average cooling rate of the sample in the simulation process and the average cooling rate of the sample in the experiment process is less than or equal to 10%.
Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.
Claims (6)
1. The method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process is characterized by comprising the following steps of:
step 1: assembling an experimental device and measuring the surface roughness of an experimental mold and a sample, wherein the experimental device comprises an upper mold, the sample, a positioning pin, a lower mold, a first thermocouple, a second thermocouple, a third thermocouple, a fourth thermocouple and a fifth thermocouple, the sample is installed on the lower mold, the positioning pin is installed on the edge of the lower mold, a plurality of positioning pins are arranged to position the sample, the upper mold can move downwards to perform hot stamping on the sample, and the sample is a rolled plate;
step 2: a plurality of thermocouples for collecting temperature are horizontally arranged on the experiment mould and the sample, the thermocouples are connected with a temperature collecting module to carry out a hot stamping experiment, and the temperature of the experiment mould and the temperature of the sample are collected at intervals of unit time t in the hot stamping experiment process;
and step 3: outputting a temperature-time curve of the sample in the experimental process, and calculating a pre-estimated interface heat exchange coefficient;
and 4, step 4: establishing a micro-scale finite element simulation model according to the surface roughness of the experimental mould and the sample; according to the surface roughness of the experimental mold and the sample, the surface of the sample, which is in contact with the experimental mold, is in a curved surface shape with wave crests and wave troughs, and the curved surface shape is drawn by adopting a spline curve; the experimental mould is designed to be a rigid body, and does not deform in the stamping process; designing the sample as an elastic plastic body, wherein the sample can be subjected to plastic deformation in the stamping process; setting a simulation model of the sample by adopting a mesh repartitioning function;
and 5: inputting a predicted interface heat exchange coefficient to perform finite element simulation analysis;
step 6: outputting a temperature-time curve of the sample in the finite element simulation process;
and 7: comparing whether the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experimental process, and calculating the average cooling rate of the sample in the experimental process; calculating the average cooling rate of the sample in the simulation process, comparing whether the deviation between the average cooling rate of the sample in the simulation process and the average cooling rate of the sample in the experimental process is less than or equal to 10%, if so, judging that the temperature-time curve of the sample in the simulation process is consistent with the temperature-time curve of the sample in the experimental process, and if not, judging that the temperature-time curve is inconsistent; if yes, outputting the estimated interface heat exchange coefficient as a final result, and if not, correcting the estimated interface heat exchange coefficient and returning to the step 5.
2. The method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process according to claim 1, wherein the finite element simulation model is a two-dimensional cross-sectional model.
3. The method for measuring the interface heat transfer coefficient of the aluminum alloy hot stamping process according to claim 1, wherein the dimension of the sample in the width direction is 100 μm to 2000 μm.
4. The method for measuring the interface heat exchange coefficient of the aluminum alloy hot stamping process according to claim 1, wherein when the sample is subjected to the mesh subdivision function setting, the unilateral length of the mesh is not more than 0.6 μm.
5. The method for measuring the heat exchange coefficient of the interface in the aluminum alloy hot stamping process according to claim 1, wherein the step 7 of correcting the estimated heat exchange coefficient of the interface comprises the following specific steps: reducing the estimated interface heat exchange coefficient if the average cooling rate of the sample in the simulation process is greater than the average cooling rate of the sample in the experiment process; and if the average cooling rate of the sample in the simulation process is smaller than the average cooling rate of the sample in the experiment process, the estimated interface heat exchange coefficient is increased.
6. The method for measuring the interface heat transfer coefficient of the aluminum alloy hot stamping process according to claim 1, wherein the value of the unit time t is 0.02 s.
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| CN104698030A (en) * | 2015-03-27 | 2015-06-10 | 中南林业科技大学 | Determination method for interface heat transfer coefficient in casting process |
| CN106841281A (en) * | 2016-12-13 | 2017-06-13 | 西北工业大学 | A kind of measuring method of the aluminum alloy surface coefficient of heat transfer |
| CN107907563B (en) * | 2017-12-28 | 2023-08-29 | 上汽通用五菱汽车股份有限公司 | Hot stamping measurement tool and application method thereof |
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