Continuous casting billet head starting pulling control method

Abstract

The invention provides a continuous casting billet head starting pulling control method which comprises the following steps: adjusting the cooling water flow of a crystallizer in real time according to an obtained inlet and return water temperature difference control range, so that the real-time inlet and return water temperature difference T1 of the crystallizer is kept within the obtained inlet and return water temperature difference control range; controlling the pulling movement process of the blank head in real time according to the obtained blank head speed pulling control parameter and the speed holding time parameter; the speed pull-up control parameters comprise a first acceleration a1 and a first uniform speed v1; a second acceleration a2 and a second uniform velocity v2; a third accelerated speed a3 and a third uniform speed v3; the speed holding time parameter comprises first holding time t1; a second retention time t2; the third holding time is t3. By means of the method, reasonable control over the billet head cooling process of the crystallizer can be effectively achieved, meanwhile, reasonable matching between the billet head cooling process and the billet head moving speed can be achieved, and therefore the billet head can be effectively and smoothly pulled out, and meanwhile tearing breakout accidents cannot happen.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting processes, and specifically to a control method for starting and pulling the head of a continuous casting billet. Background Art

[0002] In the technical field of cast iron production, it is often divided into die casting method and continuous casting method (abbreviated as continuous casting). Due to the advantages of simple process flow, high metal recovery rate, low energy consumption and high automation degree of the continuous casting method, most steel mills currently use the continuous casting method for the processing and manufacturing of cast iron.

[0003] During the starting pouring process of continuous casting, the connecting part between the dummy bar head and the billet head is the key part to ensure the smooth pulling of the continuous casting billet out of the secondary cooling chamber. Therefore, the strength of the dovetail groove of the billet head is the key point of the key part.

[0004] The residence time of the billet head in the mold (the residence time is directly related to the moving speed of the dummy bar head set in each starting stage) and the cooling capacity of the mold (the cooling capacity is related to the temperature difference and flow rate of the cooling water entering and leaving) directly affect the structural strength of the billet head. When the cooling intensity of the billet head is insufficient and the acceleration speed of the straightening force applied by the dummy bar head to the billet head is too fast (the acceleration speed of the straightening force is directly related to the moving speed of the dummy bar head set in each starting stage), when the dovetail groove of the billet head is pulled out from the outlet of the mold, it is no longer restricted by the side limit of the mold, and then the dovetail groove is easily bent directly, and bending may cause local tearing of the billet head. When the tearing phenomenon is more serious, a breakout accident will occur. Therefore, how to effectively match the cooling of the billet head with the moving speed is a technical problem to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to provide a control method for starting and pulling the head of a continuous casting billet. By using this method, it is possible to effectively control the cooling process of the billet head by the mold, and at the same time, it is possible to reasonably match the cooling process of the billet head with the moving speed of the billet head, so as to effectively pull out the billet head smoothly without breakout and tearing accidents.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a control method for starting and pulling the head of a continuous casting billet, According to the obtained control range of the temperature difference between the inlet and outlet water, the cooling water flow rate of the mold is adjusted in real time, so that the real-time temperature difference △T1 between the inlet and outlet water of the mold is maintained within the obtained control range of the temperature difference between the inlet and outlet water; According to the obtained billet head speed increase control parameters and speed holding time parameters, the pulling movement process of the billet head is controlled in real time; The speed increase control parameters include: The first acceleration a1 and the first uniform velocity v1; the first uniform velocity v1 is the moving velocity reached after the blank head starts from rest and continuously accelerates at the first acceleration a1 for a certain period of time; The second acceleration a2 and the second uniform velocity v2; the second uniform velocity v2 is the moving velocity reached after the blank head starts from the first uniform velocity v1 and continuously accelerates at the second acceleration a2 for a certain period of time; The third acceleration a3 and the third uniform velocity v3; the third uniform velocity v3 is the moving velocity reached after the blank head starts from the second uniform velocity v2 and continuously accelerates at the third acceleration a3 for a certain period of time; The velocity holding time parameters include: the first holding time t1; the second holding time t2; the third holding time t3; The first holding time t1 is the time period during which the blank head maintains uniform motion at the first uniform velocity v1 after the velocity of the blank head reaches the first uniform velocity v1; The second holding time t2 is the time period during which the blank head maintains uniform motion at the second uniform velocity v2 after the velocity of the blank head reaches the second uniform velocity v2; The third holding time t3 is the time period during which the blank head maintains uniform motion at the third uniform velocity v3 after the velocity of the blank head reaches the third uniform velocity v; Preferably, the control range of the inlet and return water temperature difference is 7 - 9°C.

[0007] Further, when △T1 < 7°C or △T1 > 9°C, the flow rate of the cooling water in the crystallizer is adjusted so that △T1 returns to the control range of the inlet and return water temperature difference. During the adjustment process of the cooling water flow rate in the crystallizer, when 7.8°C ≤ △T1 ≤ 8.2°C, the adjustment of the cooling water flow rate in the crystallizer is stopped, and the cooling water flow rate in the crystallizer is maintained at the existing flow rate parameters and continues to operate.

[0008] Further, When the motion state of the blank head is in the first stretching stage, that is, the blank head is in the stage of starting from rest and continuously accelerating at the first acceleration a1 until it reaches the first uniform velocity v1, when △T1 < 7°C occurs, the blank head stops further accelerating and maintains the existing moving velocity and continues to move at a uniform speed. During the continuous movement of the blank head, the flow rate of the cooling water in the crystallizer is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the blank head continues to accelerate at the first acceleration a1 until the moving velocity of the blank head reaches the first uniform velocity v1; When the motion state of the blank head is in the first holding stage, that is, the blank head is in the uniform motion stage with the first uniform speed v1 as the moving speed; when △T1 < 7°C occurs, the blank head continues to maintain uniform motion, and synchronously and real-time adjusts the cooling water flow rate of the mold to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the time t4 used from △T1 < 7°C to 7.8°C ≤ △T1 ≤ 8.2°C is statistically counted, and the duration of the first holding stage of the blank head becomes t1 + t4; When the motion state of the blank head is in the second lifting stage, that is, the blank head is in the stage of continuously accelerating from the first uniform speed v1 with the second acceleration a2 to the second uniform speed v2. When △T1 < 7°C occurs, the blank head stops accelerating and maintains the existing moving speed to continue uniform motion. During the continuous movement of the blank head, the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the blank head continues to accelerate with the second acceleration a2 as the acceleration until the moving speed of the blank head reaches the second uniform speed v2; When the motion state of the blank head is in the second holding stage, that is, the blank head is in the uniform motion stage with the second uniform speed v2 as the moving speed; when △T1 < 7°C occurs, the blank head continues to maintain uniform motion, and synchronously and real-time adjusts the cooling water flow rate of the mold to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the time t5 used from △T1 < 7°C to 7.8°C ≤ △T1 ≤ 8.2°C is statistically counted, and the duration of the second holding stage of the blank head becomes t2 + t5; When the motion state of the blank head is in the third lifting stage, that is, the blank head is in the stage of continuously accelerating from the second uniform speed v2 with the second acceleration a3 to the third uniform speed v3. When △T1 < 7°C occurs, the blank head stops accelerating and maintains the existing moving speed to continue uniform motion. During the continuous movement of the blank head, the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the blank head continues to accelerate with the third acceleration a3 as the acceleration until the moving speed of the blank head reaches the third uniform speed v3.

[0009] Further, the first acceleration a1 is 10 dm / min 2 , the first uniform speed v1 is 40 cm / min, and the first holding time t1 is 50 s; the second acceleration a2 is 2 dm / min 2 , the second uniform speed v2 is 80 cm / min, and the second holding time t2 is 60 s; the third acceleration a3 is 2 dm / min 2, the third uniform speed v3 is 100 cm / min, and the third holding time t3 is 60 s.

[0010] The beneficial effects of the present invention are as follows: In this control method, by regulating the cooling water flow rate of the mold in real time, reasonable control of the inlet and return water temperature difference can be achieved, and then control of the cooling process of the billet head by the mold can be realized; by setting a reasonable moving speed curve of the dummy bar head (including the speed values, speed increase acceleration values, and uniform holding time values at each stage), it is convenient to cooperate with the cooling process of the billet head in the mold, and ultimately reasonable cooling of the billet head can be achieved, enabling the dummy bar head to smoothly pull out the billet head. At the same time, during the pulling process, the change process of the straightening force is relatively stable, effectively avoiding the occurrence of accidents such as billet head tearing and steel leakage; the relatively stable change process of the straightening force is conducive to achieving the stability of the molten steel level in the mold, and is also conducive to the floating of impurities in the mold, thereby improving the safety of continuous casting and the quality of the cast billet. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some preferred embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0012] Figure 1 It is a moving speed curve diagram of the billet head starting stage in the first specific implementation of the present invention; Detailed Embodiments The following will combine specific embodiments and attached Figure 1 ..., the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some preferred embodiments of the present invention, rather than all embodiments. Those skilled in the art can make similar deformations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0013] In the continuous casting process, the mold is used to continuously cool the molten steel, and the dummy bar is used to pull out the billet head of the first billet from the bottom of the mold to achieve subsequent continuous casting. The dummy bar head of the dummy bar is initially located at the inner bottom of the mold. After the molten steel at the bottom of the mold cools, it is connected to the dummy bar head, and then it is convenient to use the dummy bar to slowly pull out the billet head of the first billet from the mold.

[0014] The present invention provides a control method for starting and pulling the billet head of continuous casting billets, including the following steps: According to the obtained control range of the inlet and return water temperature difference, the cooling water flow rate of the mold is adjusted in real time, so that the real-time inlet and return water temperature difference △T1 of the mold is maintained within the obtained control range of the inlet and return water temperature difference; in the actual application process, the parameter range of the inlet and return water temperature difference of the mold is set manually through the control terminal, and the inlet and return water temperature data are collected by the temperature sensors set in the cooling system of the mold and transmitted to the control terminal in real time. The control terminal realizes the real-time control of the cooling water flow rate by controlling the operating frequency of the water delivery pump of the cooling water of the mold, and then can realize the effective and reasonable control of the inlet and return water temperature difference of the mold, so that the inlet and return water temperature difference of the mold is maintained within the set range. When the inlet and return water temperature difference operates within the set reasonable range, it can ensure the stable cooling process of the mold for the billet and the billet head. On the basis of the stable cooling process, the reasonable control of the moving speed of the billet head can be realized, and finally the reasonable cooling intensity of the billet head in the mold can be achieved, so that there is no tearing or even steel leakage phenomenon when the billet head is pulled out of the mold; According to the obtained billet head speed lifting control parameters and speed holding time parameters, the pulling movement process of the billet head is controlled in real time; in the actual application process, the lifting control parameters and speed holding parameters of the billet head are both set manually through the control end face, and the size of each parameter can be specifically set according to actual experience. The control end uses the set parameters to implement the control of the specific movement process of the dummy bar, and then realizes the reasonable movement of the dummy bar. The reasonable movement of the dummy bar can make the drawing force received by the dovetail groove of the billet head change gently, and then effectively prevent the billet head from tearing; The speed lifting control parameters include: The first acceleration a1 and the first uniform speed v1; the first uniform speed v1 is the moving speed reached after the billet head starts from rest and accelerates continuously with the first acceleration a1 for a certain time; in the actual application process, when the molten steel is poured into the mold and after a certain time, the controller starts the straightening machine to pull the dummy bar at the starting stage. At this time, the billet head starts from rest and accelerates stably with the first acceleration a1 until the moving speed reaches the first uniform speed v1; The second acceleration a2 and the second uniform speed v2; the second uniform speed v2 is the moving speed reached after the billet head accelerates continuously with the second acceleration a2 from the first uniform speed v1 for a certain time; The third acceleration a3 and the third uniform speed v3; the third uniform speed v3 is the moving speed reached after the billet head accelerates continuously with the third acceleration a3 from the second uniform speed v2 for a certain time; The speed holding time parameters include: the first holding time t1; the second holding time t2; the third holding time t3; The first holding time t1 is the time period during which, after the speed of the billet head reaches the first uniform speed v1, the billet head moves at a uniform speed with the first uniform speed v1. The second holding time t2 is the time period during which, after the speed of the billet head reaches the second uniform speed v2, the billet head moves at a uniform speed with the second uniform speed v2. The third holding time t3 is the time period during which, after the speed of the billet head reaches the third uniform speed v3, the billet head moves at a uniform speed with the third uniform speed v3. In practical applications, after the billet head continuously moves at the third uniform speed v3 for the third holding time t3, the billet head can continuously move in the subsequent process at the third uniform speed v3. At this time, the smooth pulling out of the billet head inside the mold has been achieved.

[0015] Through the setting of the above parameters, the specific process for the control end to realize the starting to lasting stable movement of the billet head in the mold is as follows: After the straightening machine receives the start command, it starts and pulls the billet head to continuously accelerate with the first acceleration a1 (before the leading head of the dummy bar is separated from the billet head, the billet head always moves synchronously with the dummy bar). When the moving speed of the billet head reaches the first uniform speed v1, the billet head stops accelerating and moves at a uniform speed with the first uniform speed v1. When the billet head moves at a uniform speed with the first uniform speed v1 for the first holding time t1, the billet head continuously accelerates with the second acceleration a2. When the moving speed of the billet head reaches the second uniform speed v2, the billet head stops accelerating and moves at a uniform speed with the second uniform speed v2. When the billet head moves at a uniform speed with the second uniform speed v2 for the second holding time t2, the billet head continuously accelerates with the third acceleration a3. When the moving speed of the billet head reaches the third uniform speed v3, the billet head stops accelerating and moves at a uniform speed with the third uniform speed v3. When the billet head moves at a uniform speed with the third uniform speed v3 for the third holding time t3, the billet head moves at a lasting uniform speed with the third uniform speed v3.

[0016] On the basis of the above embodiments, combined with the actual operation of the existing mold, the control range of the inlet and return water temperature difference can be 7 - 9°C. By controlling the inlet and return water temperature difference of the mold to realize the regulation of the cooling capacity of the mold, the influence of the change of the inlet water temperature caused by the day-night temperature difference or seasonal changes on the cooling capacity of the mold can be effectively avoided. Subsequently, the stable cooling effect of the mold can be maintained for a long time. Therefore, under the condition of stable cooling capacity of the mold, it is convenient to realize the stable control of the moving speed of the billet head in the mold.

[0017] In practical applications, when the temperature difference between the inlet and outlet water of the mold fluctuates around 7°C or 9°C, the control end frequently adjusts the cooling water flow of the mold, which in turn causes the flow rate of the cooling water to continuously fluctuate, and thus is not conducive to achieving stable cooling of the molten steel by the mold. To prevent the flow rate of the cooling water from continuously fluctuating, here, when △T1 < 7°C or △T1 > 9°C, the flow rate of the cooling water of the mold is adjusted so that △T1 returns to the control range of the temperature difference between the inlet and outlet water. During the adjustment process of the cooling water flow rate of the mold, when 7.8°C ≤ △T1 ≤ 8.2°C, the adjustment of the cooling water flow rate of the mold is stopped, and the cooling water flow rate of the mold is maintained to continue running with the existing flow rate parameters. Since the difference between 7.8°C and 7°C and between 8.2°C and 9°C is both 0.8°C, in the subsequent cooling process, even if △T1 is not between 7.8°C and 8.2°C, as long as it is still within the range of 7°C to 9°C, the controller will still not adjust the flow rate of the mold, so that the cooling water flow rate of the cooling system of the mold can be kept stable for a certain period of time, thereby reducing the flow rate fluctuation of the cooling water.

[0018] On the basis of the above embodiment, by combining the change factor of the temperature difference between the inlet and outlet water of the mold on the basis of controlling the moving speed of the billet head, the specific implementation manner of the first specific embodiment for specifically controlling the moving speed of the billet head is as follows: When the motion state of the billet head is in the first lifting stage, that is, the billet head is in the stage of starting from rest and continuously accelerating with the first acceleration a1 until reaching the first uniform speed v1. When △T1 < 7°C occurs, the billet head stops accelerating and continues to move at a constant speed with the existing moving speed. During the continuous movement of the billet head, the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the billet head continues to accelerate with the first acceleration a1 until the moving speed of the billet head reaches the first uniform speed v1. When the motion state of the billet head is in the first holding stage, that is, the billet head is in the uniform moving stage with the first uniform speed v1; when △T1 < 7°C occurs, the billet head continues to move at a constant speed, and the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the time t4 used from △T1 < 7°C to 7.8°C ≤ △T1 ≤ 8.2°C is counted, and the duration of the first holding stage of the billet head is changed to t1 + t4. When the moving state of the blank head is in the second pulling stage, that is, the blank head is in the stage of continuously accelerating from the first uniform speed v1 with the second acceleration a2 until reaching the second uniform speed v2. When △T1 < 7°C occurs, the blank head stops accelerating and maintains the existing moving speed to continue uniform motion. During the continuous movement of the blank head, the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the blank head continues to accelerate with the second acceleration a2 until the moving speed of the blank head reaches the second uniform speed v2; When the moving state of the blank head is in the second holding stage, that is, the blank head is in the uniform moving stage with the second uniform speed v2 as the moving speed; when △T1 < 7°C occurs, the blank head continues to maintain uniform motion, and the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the time t5 used from △T1 < 7°C to 7.8°C ≤ △T1 ≤ 8.2°C is counted, and the duration of the second holding stage of the blank head becomes t2 + t5; When the moving state of the blank head is in the third pulling stage, that is, the blank head is in the stage of continuously accelerating from the second uniform speed v2 with the second acceleration a3 until reaching the second uniform speed v3. When △T1 < 7°C occurs, the blank head stops accelerating and maintains the existing moving speed to continue uniform motion. During the continuous movement of the blank head, the cooling water flow rate of the mold is synchronously and real-time adjusted to achieve the adjustment of △T1. When 7.8°C ≤ △T1 ≤ 8.2°C, the blank head continues to accelerate with the third acceleration a3 until the moving speed of the blank head reaches the third uniform speed v3.

[0019] In the above embodiments, the specific values of each control parameter are: the first acceleration a1 is 10 dm / min 2 , the first uniform speed v1 is 40 cm / min, and the first holding time t1 is 50 s; the second acceleration a2 is 2 dm / min 2 , the second uniform speed v2 is 80 cm / min, and the second holding time t2 is 60 s; the third acceleration a3 is 2 dm / min 2 , the third uniform speed v3 is 100 cm / min, and the third holding time t3 is 60 s.

[0020] In the present invention, "up", "down", "front", "back", "left", and "right" are all relative positions used for conveniently describing the position relationship, and thus cannot be understood as absolute positions to limit the protection scope.

[0021] Except for the technical features described in the specification, they are all known technologies to those skilled in the art.

[0022] The preferred embodiments and examples of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to the above-mentioned embodiments and examples. For those of ordinary skill in the art, without departing from the concept of the present invention, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for controlling the starting pulling of a continuous casting slab head, characterized in that: According to the obtained inlet and return water temperature difference control range, the cooling water flow rate of the crystallizer is adjusted in real time so that the real-time inlet and return water temperature difference ΔT1 of the crystallizer is maintained within the obtained inlet and return water temperature difference control range; According to the acquired billet head speed raising control parameters and speed holding time parameters, the billet head pulling motion process is controlled in real time; The speed increase control parameters include: The first acceleration a1 and the first uniform velocity v1; the first uniform velocity v1 is the moving velocity reached after the blank head starts from rest and accelerates continuously for a certain period of time with the first acceleration a1 as the acceleration; The second acceleration a2, the second uniform speed v2; the second uniform speed v2 is the moving speed of the blank head after accelerating for a certain period of time from the first uniform speed v1 with the second acceleration a2 as the acceleration; The third acceleration a3, the third uniform speed v3; the third uniform speed v3 is the moving speed of the blank head after accelerating for a certain period of time from the second uniform speed v2 with the third acceleration a3 as the acceleration; The speed holding time parameters include: first holding time t1; second holding time t2; third holding time t3; The first holding time t1 is the time period during which the billet head keeps moving at the first uniform speed v1 after the speed of the billet head reaches the first uniform speed v1; The second holding time t2 is the time period during which the billet head keeps moving at the second uniform speed v2 after the speed of the billet head reaches the second uniform speed v2; The third holding time t3 is the time period during which the billet head keeps moving at the third uniform speed v3 after the speed of the billet head reaches the third uniform speed v.

2. A continuous casting slab head starting pulling control method according to claim 1, characterized in that: The inlet and return water temperature difference control range is 7°C≤△T1≤9°C.

3. A continuous casting slab head starting pulling control method according to claim 2, characterized in that When △T1<7℃ or △T1>9℃, the flow rate of cooling water of the crystallizer is adjusted so that △T1 returns to the control range of the inlet and return water temperature difference. During the adjustment process of the cooling flow rate of the crystallizer, when 7.8℃≤△T1≤8.2℃, the adjustment of the cooling water flow rate of the crystallizer is stopped, and the cooling water flow rate of the crystallizer is maintained at the existing flow parameters for continuous operation.

4. A continuous casting slab head starting pulling control method according to claim 3, characterized in that: When the motion state of the billet head is in the first lifting stage, that is, the billet head is in the stage of starting from rest and continuously accelerating with the first acceleration a1 as the acceleration to the first uniform speed v1, when △T1<7℃, the billet head stops accelerating and maintains the existing moving speed to continue to move at a uniform speed. During the continuous movement of the billet head, the cooling water flow of the crystallizer is synchronously and real-timely regulated to achieve the adjustment of △T1. When 7.8℃≤△T1≤8.2℃, the billet head continues to accelerate with the first acceleration a1 as the acceleration until the moving speed of the billet head reaches the first uniform speed v1; When the motion state of the blank head is in the first holding stage, that is, the blank head is in a uniform moving stage with a first uniform speed v1 as the moving speed; When △T1<7℃, the billet head continues to move at a uniform speed, and the cooling water flow of the crystallizer is synchronously controlled in real time to achieve the adjustment of △T1. When 7.8℃≤△T1≤8.2℃, the time t4 used when △T1<7℃ to 7.8℃≤△T1≤8.2℃ is counted, and the time of the first holding stage of the billet head is changed to t1+t4; When the motion state of the billet head is in the second lifting stage, that is, the billet head is in the stage of continuously accelerating from the first uniform velocity v1 and accelerating at the second acceleration a2 to the second uniform velocity v2, when △T1<7℃, the billet head stops accelerating and maintains the current moving speed to continue to move at a uniform speed. During the continuous movement of the billet head, the cooling water flow of the crystallizer is synchronously and real-timely regulated to achieve the adjustment of △T1. When 7.8℃≤△T1≤8.2℃, the billet head continues to accelerate at the second acceleration a2 until the moving speed of the billet head reaches the second uniform velocity v2; When the motion state of the blank head is in the second holding stage, that is, the blank head is in a uniform moving stage with a second uniform speed v2 as the moving speed; When △T1<7℃, the billet head continues to move at a uniform speed, and the cooling water flow of the crystallizer is synchronously controlled in real time to achieve the adjustment of △T1. When 7.8℃≤△T1≤8.2℃, the time t5 used when △T1<7℃ to 7.8℃≤△T1≤8.2℃ is counted, and the time of the second holding stage of the billet head is changed to t2+t5; When the motion state of the billet head is in the third pulling stage, that is, the billet head is in the stage of accelerating from the second uniform velocity v2 and continuously accelerating with the second acceleration a3 as the acceleration to the second uniform velocity v3, when △T1<7℃, the billet head stops accelerating and maintains the existing moving speed to continue to move at a uniform speed. During the continuous movement of the billet head, the cooling water flow of the crystallizer is synchronously and real-time regulated to achieve the adjustment of △T1. When 7.8℃≤△T1≤8.2℃, the billet head continues to accelerate with the third acceleration a3 as the acceleration until the moving speed of the billet head reaches the third uniform velocity v3.

5. A continuous casting slab head starting pulling control method according to claim 4, characterized in that: The first acceleration a1 is 10 dm / min 2 , the first uniform velocity v1 is 40 cm / min, the first holding time t1 is 50 s; the second acceleration a2 is 2 dm / min 2 The second uniform velocity v2 is 80 cm / min, the second holding time t2 is 60 s; the third acceleration a3 is 2 dm / min 2 , the third uniform speed v3 is 100 cm / min, and the third holding time t3 is 60 s.

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