A method for obtaining a flat plate-shaped simulated specimen

Abstract

The present invention provides a method for obtaining a flat plate-shaped simulation sample, comprising the following steps: dividing the heating process of the plate-shaped simulation sample from room temperature to the highest temperature into N sections, including the first section, the second section... to the Nth section; the plate-shaped simulation sample is heated in the order of the first section, the second section... to the Nth section, and each section is respectively heated according to the mode of turning on the air hammer system to apply tensile stress to the plate-shaped sample, and turning off the air hammer system to apply tensile stress to the plate-shaped sample, so as to realize the flatness control of the plate-shaped simulation sample. The method can obtain a plate-shaped sample with good plate shape after the plate strip undergoes a continuous annealing process simulation experiment, thereby improving the accuracy and efficiency of the experiment.

Description

Technical Field

[0001] The invention belongs to the technical field of hot processing technology of steel materials, and in particular relates to a method for obtaining a flat plate-shaped simulation sample. Background Art

[0002] The plate and strip annealing process can recrystallize the plate and strip material and eliminate work hardening. It is a heat treatment process that restores plasticity to obtain the expected physical and physico-chemical properties.

[0003] In order to develop high-performance cold-rolled products more quickly and efficiently, continuous annealing simulation test machines are generally used to study the relationship between the organizational properties of cold-rolled products and the annealing process. The patent number CN200510023266.9, "A strip continuous annealing process simulation device", can continuously simulate the heating, soaking, slow cooling, fast cooling, and aging process of strip steel samples in a continuous annealing furnace. However, since the strength of the plate and strip samples is low at high temperatures, the expansion of the samples during the heating and soaking process will cause the samples to bend and deform. In response to this phenomenon, the invention does not clearly propose effective measures to prevent the deformation of the plate and strip samples.

[0004] The thermal simulation test machine manufactured by the American Dynamic Systems Company can be equipped with different components or units to complete specific physical simulation experiments, and the plate strip annealing system is one of them. When using this system to conduct a plate strip annealing process simulation experiment, a constant tensile force is applied to the two ends of the plate strip sample through the clamps at both ends of the sample to keep the plate strip sample straight due to the tensile force. However, due to the structural characteristics of the system, when the plate strip is in a vacuum state, the main shaft driving the clamp holding the plate strip sample will be subject to the atmospheric pressure to produce compressive stress on the plate strip sample. This requires that the force applied to the plate strip sample should be set to be large enough to offset the force of atmospheric pressure. During the annealing process of the plate strip sample, it is necessary to spray cooling medium on the plate strip sample to cool the plate strip sample, which will destroy the vacuum state of the plate strip sample, weaken the atmospheric pressure on the main shaft driving the clamp holding the plate strip sample, thereby increasing the combined force on the plate strip sample, and the plate strip is in a tensile state, which is easy to cause tensile deformation of the plate strip sample. If the tension applied to both ends of the plate and strip specimen is too small, the plate and strip specimen may bend and deform due to thermal expansion, which will eventually affect the experimental accuracy and reduce the experimental efficiency.

[0005] In order to avoid the shortcomings of the above methods, it is necessary to develop more effective control methods to prevent the deformation of plate and strip specimens, so as to obtain plate specimens with good plate shape and improve the accuracy and efficiency of the experiment. Summary of the invention

[0006] In order to solve the above problem, the technical solution adopted by the present invention is: a method for obtaining a flat plate-shaped simulated sample, comprising the following steps:

[0007] The heating process of heating the plate-shaped simulation sample from room temperature to the highest temperature is divided into N sections, including a first section, a second section, ... to an Nth section;

[0008] The plate-shaped simulation specimen is arranged in the order of the first section, the second section... to the Nth section. Each section is heated according to the mode of turning on the air hammer system to apply tensile stress to the plate-shaped specimen, and turning off the air hammer system to apply tensile stress to the plate-shaped specimen, so as to realize the straightness control of the plate-shaped simulation specimen.

[0009] Furthermore, the heating process of the plate-shaped simulation specimen from room temperature to the highest temperature is divided into N sections using the following formula:

[0010] (1)

[0011] Where: T s It indicates the temperature at which the plate-shaped simulated specimen is heated to a state of obvious expansion, T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation, and C is a constant;

[0012] When T m ≤T s When N=3;

[0013] When T m >T s When , the value of N is calculated according to formula (1). When N is not an integer, N=[N]+1.

[0014] Furthermore, the process of calculating the heating time is as follows:

[0015] The heating rate during the heating process is recorded as v, and the total time of the heating process is recorded as t 总 Calculate according to the following formula (2):

[0016] (2)

[0017] The critical temperature at which the plate-shaped simulated specimen bends is T n When , the corresponding time period is t1, then:

[0018] (3)

[0019] From t1 to t 总 So far, according to the number of sections N calculated in formula (1), ideally: the heating time t 总 -t1 is divided into N equal parts, and the time of each segment is recorded as t0:

[0020] (4)

[0021] In actual situations, the heating time of the plate-shaped simulation specimen is transformed according to the parabolic function relationship, and the actual heating process segment time , M=1, 2, ..., N, the specific transformation process is as follows:

[0022] set up:

[0023] (5)

[0024] The last t0, that is, t 总 The conversion is carried out according to the following formula:

[0025] (6)

[0026] Among them, a and b are the unknown constants of the parabolic function;

[0027] Combining formula (5) and (6) we get:

[0028] (7)

[0029] (8)

[0030] That is, each segment time t0, 2t0, ..., Nt0 follows a parabolic function Transform, where: M = 1, 2, ..., N, the time after transformation is t z , where constants a and b are determined by formulas (7) and (8).

[0031] Furthermore, the air hammer system applies tensile stress to the plate-shaped specimen for a time period between 1 and 3 seconds.

[0032] Furthermore, the tensile stress F applied by the air hammer system to the plate-shaped specimen is calculated using the following formula:

[0033] (9)

[0034] in: is the pressure of the air hammer, is the corresponding cross-sectional area, is the outside atmospheric pressure, is the environmental pressure of the plate specimen, is the cross-sectional area acting on the main shaft of the testing machine, The friction force between the main shaft and the contact part of the thermal simulation test machine, .

[0035] Furthermore, 10N≤F≤30N.

[0036] A device for obtaining a flat plate-shaped simulated sample, comprising:

[0037] Division module: used to divide the heating process of the plate-shaped simulation specimen from room temperature to the highest temperature into N sections, including the first section, the second section... to the Nth section;

[0038] Control module: used to control the flatness of the plate-shaped simulation specimen in the order of the first section, the second section... to the Nth section, with each section applying tensile stress to the plate-shaped specimen according to the mode of heating, heating off, and air hammer system.

[0039] A readable storage medium stores a program module, wherein the program module is executed in a processor to implement any of the methods described above.

[0040] The present invention provides a method for obtaining a flat plate-shaped simulation sample, which divides the heating process of the plate-shaped sample during the annealing process into sections, and then reasonably allocates the time of each section according to the expansion characteristics of the plate-shaped sample during the heating process, and finally applies tensile stress to the plate-shaped sample by opening and closing the air hammer system of the thermal simulation test machine to offset the expansion of the plate-shaped sample, thereby better controlling the flatness of the plate-shaped sample during the annealing experiment, which can improve both the experimental accuracy and the experimental success rate. This method obtains a plate-shaped sample with good plate shape after the plate strip undergoes a continuous annealing process simulation experiment, thereby improving the accuracy and efficiency of the experiment. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] A method for obtaining a flat plate-shaped simulated sample comprises the following steps:

[0044] S1: Divide the heating process of the plate-shaped simulation sample from room temperature to the highest temperature into N sections, including the first section, the second section... to the Nth section;

[0045] S2: The plate-shaped simulation specimen is arranged in the order of the first section, the second section...to the Nth section. Each section is respectively heated according to the mode of turning on the air hammer system to apply tensile stress to the plate-shaped simulation specimen, and turning off the air hammer system to apply tensile stress to the plate-shaped simulation specimen, so as to realize the straightness control of the plate-shaped simulation specimen.

[0046] Steps S1 / S2 are executed sequentially;

[0047] The heating process of the plate-shaped simulation sample from room temperature to the highest temperature is divided into N sections using the following formula:

[0048] (1)

[0049] Where: T s It indicates the temperature at which the plate-shaped simulated specimen is heated to a state of obvious expansion, T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation process. The obvious expansion state is the state when the plate-shaped simulation sample is subjected to a force exceeding 10N. C is a constant, and C is taken as 50;

[0050] When T m ≤T s When N=3;

[0051] When T m >T s When , the value of N is calculated according to formula (1). When N is not an integer, N=[N]+1.

[0052] Furthermore, the process of calculating the time for heating the plate-shaped simulation specimen is as follows:

[0053] The heating rate during the heating process is recorded as v, and the total time of the heating process is recorded as t 总 Calculate according to the following formula (2):

[0054] (2)

[0055] The critical temperature at which the plate-shaped simulated specimen bends is T n When , the corresponding time period is t1, then:

[0056] (3)

[0057] From t1 to t 总 So far, according to the number of sections N calculated in formula (1) in step 1, ideally: the heating time t 总 -t1 is divided into N equal parts, and the time of each segment is recorded as t0:

[0058] (4)

[0059] In actual situations, the heating time of the plate-shaped simulation specimen is transformed according to the parabolic function relationship, and the actual heating process segment time , M=1, 2, ..., N, the specific transformation process is as follows:

[0060] set up:

[0061] (5)

[0062] The last t0, that is, t 总 The conversion is carried out according to the following formula:

[0063] (6)

[0064] Among them, a and b are the unknown constants of the parabolic function;

[0065] Combining formula (5) and (6) we get:

[0066] (7)

[0067] (8)

[0068] That is, each segment time t0, 2t0, ..., Nt0 follows a parabolic function Transform, where: M = 1, 2, ..., N, the time after transformation is t z , that is, t z = , where constants a and b are determined by formulas (7) and (8).

[0069] Furthermore, the air hammer system applies tensile stress to the plate-shaped specimen for a time period between 1 and 3 seconds.

[0070] One of the driving forces of the thermal simulation test machine is the air hammer system, which can drive the main shaft of the test machine and the fixture on it to move forward and backward, thereby applying tension and pressure to the plate and strip specimen clamped on the fixture. The tensile stress F applied by the air hammer system to the plate specimen is calculated using the following formula:

[0071] (9)

[0072] in: is the pressure of the air hammer, is the corresponding cross-sectional area, is the outside atmospheric pressure, is the environmental pressure of the plate specimen, is the cross-sectional area acting on the main shaft of the testing machine, The friction force between the main shaft and the contact part of the thermal simulation test machine, .

[0073] In order to avoid F being too large, which may cause the plate and strip specimen to be subjected to tensile stress and tensile deformation, 10N≤F≤30N.

[0074] The control of the annealing process simulation experiment of the plate sample is based on the time interval after the conversion, and at each time point, for example, t1+t z At this moment, the air hammer system of the thermal simulation test machine is turned on, and the air hammer system generates tensile stress on the plate specimen for a duration of t s After t seconds, as the temperature of the plate specimen continues to rise, when it reaches the second time point, the air hammer system of the thermal simulation test machine is turned on again, and the air hammer system generates tensile stress on the plate specimen for a duration of t s It is turned on and off after 1 second. In this way, at each time segment node, the air hammer system of the thermal simulation testing machine is turned on and off to apply tensile stress to the plate-shaped specimen to offset the expansion of the plate-shaped specimen, thereby better controlling the flatness of the plate-shaped specimen during the annealing experiment.

[0075] A device for obtaining a flat plate-shaped simulated sample, comprising:

[0076] Division module: used to divide the heating process of the plate-shaped simulation specimen from room temperature to the highest temperature into N sections, including the first section, the second section... to the Nth section;

[0077] Control module: used to control the flatness of the plate-shaped simulation specimen in the order of the first section, the second section... to the Nth section, with each section applying tensile stress to the plate-shaped specimen according to the mode of heating, heating off, and air hammer system.

[0078] A readable storage medium stores a program module, wherein the program module is executed in a processor to implement any of the methods described above.

[0079] Embodiment 1:

[0080] The plate sample material selected is a low-carbon low-alloy steel, and the plate sample size is 50×180×1.5mm. A plate sample is taken for plate strip annealing process simulation experiment. The experimental process procedure is: on the thermal simulation test machine, the plate strip sample is heated to a maximum of 900℃ at a heating rate of 10℃ / s, kept at this temperature for 3 minutes, and then cooled to room temperature at a cooling rate of 10℃ / s.

[0081] S1. The temperature T at which the selected plate-shaped specimen is heated to a state of obvious expansion s=500°C, according to formula (1), the heating section N is calculated to be 11, that is, the heating process is divided into 11 sections according to formula (1);

[0082] The calculation of total heating time and N-section heating process time is as follows:

[0083] According to formula (2), the total time of the heating process is calculated as ttotal = 90 seconds, and the critical temperature of the plate-shaped simulation specimen bending is T n =300℃, the corresponding time period is t1=30 seconds, and t0=5.45 seconds is calculated by formula (4);

[0084] Actual heating process segment time The transformation is based on the parabolic function relationship. When M=1, 2, ..., the transformation is calculated according to formulas (5) and (6): , ,

[0085] The plate shape simulation specimen is then The transformation results are shown in Table 1.

[0086] Table 1

[0087]

[0088] Adjust the air hammer loading force, and now set the resultant force of the thermal simulation test machine spindle acting on the sample to 20 Newtons. According to formula (9), the air hammer pressure needs to be set to 1.2 MPa.

[0089] S2: Control the annealing process simulation experiment process of the plate-shaped sample. According to the time interval converted in step 3, at each time point, the air hammer system of the thermal simulation test machine is turned on, so that the air hammer system generates tensile stress on the plate-shaped sample, which lasts for 1 second and then is turned off, applying tensile stress to the plate-shaped sample to offset the expansion of the plate-shaped sample, so that the plate shape of the plate-shaped sample can be better controlled during the annealing experiment. The control process is shown in Table 2.

[0090] Table 2

[0091]

[0092] Embodiment 2:

[0093] The material of the plate specimen is a low-carbon low-alloy steel, and the size of the plate specimen is 50×180×1.5mm. A plate specimen is taken for the plate strip annealing process simulation experiment. The test process procedure is as follows: on a thermal simulation test machine, the plate strip specimen is heated to a maximum temperature of 700°C at a heating rate of 10°C / s, kept at this temperature for 3 minutes, and then cooled to room temperature at a cooling rate of 10°C / s.

[0094] S1: The selected plate-shaped specimen is heated to temperature T s =500°C, according to formula (1), the heating section N is calculated to be 11, that is, the heating process is divided into 7 sections according to formula (1);

[0095] Calculation of total heating time and N-segment heating process time. Calculate the total time t in the heating process according to formula (2): 总 = 70 seconds, the critical temperature for the plate specimen to bend is T n =300℃, the corresponding time period is t1=30 seconds, and t0=5.71 seconds is calculated by formula (4);

[0096] Actual heating process segment time The transformation of is based on the parabolic function relationship. When M=1, 2, ... 7, the transformation is calculated according to formulas (5) and (6): ,

[0097] The plate shape simulation specimen is then The transformation results are shown in Table 3.

[0098] Table 3

[0099]

[0100] Adjust the air hammer loading force, and now apply the resultant force of the thermal simulation test machine spindle to the sample Set to 20 Newtons. According to formula (9), the air hammer pressure needs to be set to 1.2 MPa.

[0101] S2: Control the annealing process simulation experiment process of the plate-shaped sample. According to the time interval converted in step Table 3, at each time point, the air hammer system of the thermal simulation test machine is turned on, so that the air hammer system generates tensile stress on the plate-shaped sample, which lasts for 1 second and then is turned off, applying tensile stress to the plate-shaped sample to offset the expansion of the plate-shaped sample, so that the plate shape of the plate-shaped sample can be better controlled during the annealing experiment. The control process is shown in Table 4.

[0102] Table 4

[0103]

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 method for obtaining a flat plate-shaped simulated sample, characterized in that: The following steps are involved: The heating process of heating the plate-shaped simulation sample from room temperature to the highest temperature is divided into N sections, including a first section, a second section, ... to an Nth section; The plate-shaped simulation specimen is arranged in the order of the first section, the second section, ... to the Nth section, and each section is respectively heated according to the mode of turning on the air hammer system to apply tensile stress to the plate-shaped simulation specimen, and turning off the air hammer system to apply tensile stress to the plate-shaped simulation specimen, so as to realize the straightness control of the plate-shaped simulation specimen; The heating process of the plate-shaped simulation sample from room temperature to the highest temperature is divided into N sections using the following formula: （1） Where: T s It indicates the temperature at which the plate-shaped simulated specimen is heated to a state of obvious expansion, T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation, and C is a constant; When T m ≤T s When N=3; When T m >T s When the heating time is , the value of N is calculated according to formula (1). When N is not an integer, N=[N]+1. The process of calculating the heating time is as follows: The heating rate during the heating process is recorded as v, and the total time of the heating process is recorded as t 总 , calculated according to the following formula (2): （2） Where: T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation. The critical temperature at which the plate-shaped simulated specimen bends is T n When , the corresponding time period is t1, then: （3） From t1 to t 总 Until then, according to the number of sections N calculated in formula (1), this heating time t 总 -t1 is divided into N equal parts, and the time of each segment is recorded as t0: （4） In actual situations, the heating time of the plate-shaped simulation specimen is transformed according to the parabolic function relationship, and the actual heating process segment time , M=1, 2, ..., N, the specific transformation process is as follows: set up: （5） The last t0, that is, t 总 -t1 conversion is performed according to the following formula: （6） Among them, a and b are the unknown constants of the parabolic function; Combining formula (5) and (6) we get: （7） （8） That is, each segment time t0, 2t0, ..., Nt0 follows a parabolic function Transform, where: M = 1, 2, ..., N, the time after transformation is t z , where constants a and b are determined by formulas (7) and (8); The tensile stress F applied by the air hammer system to the plate-shaped specimen is calculated using the following formula: （9） in: is the pressure of the air hammer, is the corresponding cross-sectional area, is the outside atmospheric pressure, is the environmental pressure of the plate specimen, is the cross-sectional area acting on the main shaft of the testing machine, The friction force between the main shaft and the contact part of the thermal simulation test machine, .

2. A method for obtaining a flat plate-shaped simulated sample according to claim 1, characterized in that: The air hammer system applies tensile stress to the plate-shaped specimen for a time value between 1 and 3 seconds.

3. The method for obtaining a flat plate-shaped simulated sample according to claim 1, characterized in that: 10N≤F≤30N.

4. A device for obtaining a flat plate-shaped simulated sample, characterized in that: include: Division module: used to divide the heating process of the plate-shaped simulation specimen from room temperature to the highest temperature into N sections, including the first section, the second section... to the Nth section; Control module: used to control the flatness of the plate-shaped simulation specimen in the order of the first section, the second section, ... to the Nth section, and each section is respectively heated according to the mode of turning on the air hammer system to apply tensile stress to the plate-shaped specimen, and turning off the air hammer system to apply tensile stress to the plate-shaped specimen, so as to realize the straightness control of the plate-shaped simulation specimen; The heating process of the plate-shaped simulation sample from room temperature to the highest temperature is divided into N sections using the following formula: （1） Where: T s It indicates the temperature at which the plate-shaped simulated specimen is heated to a state of obvious expansion, T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation, and C is a constant; When T m ≤T s When N=3; When T m >T s When the heating time is , the value of N is calculated according to formula (1). When N is not an integer, N=[N]+1. The process of calculating the heating time is as follows: The heating rate during the heating process is recorded as v, and the total time of the heating process is recorded as t 总 , calculated according to the following formula (2): （2） Where: T m It indicates the highest temperature that the plate-shaped simulation sample needs to be heated to during the annealing process simulation. The critical temperature at which the plate-shaped simulated specimen bends is T n When , the corresponding time period is t1, then: （3） From t1 to t 总 Until then, according to the number of sections N calculated in formula (1), this heating time t 总 -t1 is divided into N equal parts, and the time of each segment is recorded as t0: （4） In actual situations, the heating time of the plate-shaped simulation specimen is transformed according to the parabolic function relationship, and the actual heating process segment time , M=1, 2, ..., N, the specific transformation process is as follows: set up: （5） The last t0, that is, t 总 -t1 conversion is performed according to the following formula: （6） Among them, a and b are the unknown constants of the parabolic function; Combining formula (5) and (6) we get: （7） （8） That is, each segment time t0, 2t0, ..., Nt0 follows a parabolic function Transform, where: M = 1, 2, ..., N, the time after transformation is t z , where constants a and b are determined by formulas (7) and (8); The tensile stress F applied by the air hammer system to the plate-shaped specimen is calculated using the following formula: （9） in: is the pressure of the air hammer, is the corresponding cross-sectional area, is the outside atmospheric pressure, is the environmental pressure of the plate specimen, is the cross-sectional area acting on the main shaft of the testing machine, The friction force between the main shaft and the contact part of the thermal simulation test machine, .

5. A readable storage medium storing a program module, characterized in that: The program module is executed in a processor to implement the method according to any one of claims 1 to 3.

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