CN109794517B - Strain control process for directly rolling square billet - Google Patents
Strain control process for directly rolling square billet Download PDFInfo
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- CN109794517B CN109794517B CN201811651322.7A CN201811651322A CN109794517B CN 109794517 B CN109794517 B CN 109794517B CN 201811651322 A CN201811651322 A CN 201811651322A CN 109794517 B CN109794517 B CN 109794517B
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Abstract
A strain control process for directly rolling a square billet belongs to the technical field of long profile processing processes. Performing induction heat compensation, temperature compensation of a temperature-equalizing furnace and temperature-equalizing pit mode temperature equalization and strain deformation control on a square billet, and performing accelerated cooling before rolling in each pass, wherein the temperature of the center of the surface of the billet is controlled to be 750-1200 ℃ and the billet enters a rolling mill for rolling; and (3) calculating the detection value of the surface temperature of the continuous casting square billet after the temperature equalization through a mathematical model, and setting the pressure of a medium for accelerating cooling so that the surface center temperature of the square billet and the core part generate a larger temperature gradient of 50-400 ℃, and improving the strain of the center of the square billet through controlled rolling. The method has the advantages that the method can weld the defects of looseness, shrinkage cavity and cracks of the square billet core part, and improve the comprehensive quality of rolled steel.
Description
Technical Field
The invention belongs to the technical field of steel processing technology. Mainly relates to a strain control method for directly rolling a square billet, which is suitable for rolling the square billet.
Background
After the continuous casting square billet is taken out of the continuous casting machine and cut off, the square billet is distributed in a temperature field with gradually reduced temperature from the core part to the surface due to high-temperature radiation heat dissipation, heat convection with air and conduction heat transfer with a conveying roller way, and the deformation resistance of the cross section of the corresponding square billet is in stepped distribution from inside to outside. In the direct rolling process of the square billet after temperature equalization in the modes of induction heat compensation, uniform temperature furnace heat compensation, uniform temperature pits and the like, the temperature field of the cross section of the square billet tends to be uniformly distributed.
When a rolled piece is rolled, because friction force exists between the rolled piece and a roller and the temperature field of the cross section of a square billet is not uniform, deformation stress distribution in the height direction of the section of the rolled piece is not uniform when the square billet is deformed, and metal flow distribution is also not uniform. During normal production, when the surface temperature of the square billet is higher than the core temperature or slightly lower than the core temperature when the square billet is taken out of the heating furnace, and the temperature difference is within +/-20 ℃, the strain deformation can not well penetrate into the center of a rolled piece, so that the core defects of the square billet are difficult to eliminate in the rolling process. The influence of the temperature difference between the surface and the core of the billet in the initial rolling stage is the largest compared with the intermediate rolling and finish rolling stages in the rolling.
The strain control process is to increase the temperature gradient of the surface and the core of the square billet in an accelerated cooling mode to cause the deformation resistance to present step distribution, namely, the surface deformation resistance is large and difficult to deform, the core deformation resistance is small and easy to deform, so that the permeation of deformation from the surface to the center is increased, the internal defects of a rolled piece are reduced, and the yield is improved.
Conventional differential rolling methods, such as: the invention discloses a differential temperature rolling method of an AlZnMgCu series aluminum alloy thick plate with a patent publication number of CN107931337A, which is a rolling control method for describing a thick plate blank; the invention discloses a novel ingot-material rolling method 101451182, which is a temperature control method for controlling the temperature of a steel ingot to be 6-12 minutes before rolling.
The present invention describes a method of increasing core strain during billet rolling.
Disclosure of Invention
The invention aims to provide a strain control process for directly rolling a square billet, wherein in the direct rolling process, the square billet is limited by the force and energy parameters of equipment, and deformation cannot well penetrate into a core part, so that internal defects such as cracks, looseness, shrinkage cavities and the like formed in the continuous casting of the square billet cannot be well eliminated, and the yield is reduced. The strain control process can solve the problems that the conventional production rolling equipment has smaller force-energy parameters and deformation can not well penetrate into the core.
The process flow of the invention comprises: continuous casting → temperature detection → heat compensation and temperature equalization → temperature detection → square billet surface accelerated cooling → controlled rolling → temperature detection → feedback control; the method is characterized in that the technical parameters controlled in the process are as follows:
1) the strain deformation control process is suitable for strain deformation control of directly rolled square billets after temperature equalization in modes of induction heat compensation, uniform temperature furnace heat compensation, uniform temperature pits and the like, and is shown in an attached figure 1. Controlling the temperature of the center of the surface of the billet at 750-1200 ℃ by accelerated cooling before each pass of rolling, and then rolling in a rolling mill;
2) accelerated cooling devices are installed before and after the rolling mill for reducing the surface temperature of the billet, resulting in an increased temperature gradient of the billet surface and core, see fig. 1. The inlet of the rolling mill is provided with a cooling system for controlling the rolling temperature of the square billet in the current pass, and the outlet of the rolling mill is provided with a cooling system for controlling the rolling temperature of the next pass. The cooling device can adopt the mixture of water, compressed air, air and water to cool the square billet, the cooling capacity of the square billet is adjusted through the pressure and the flow of a cooling medium, and the pressure of a nozzle is 0.01-2.00 MPa. Besides the adjustable cooling capacity, the position of the rolling mill is adjustable within a certain range at two sides of the rolling mill, and the adjusting range is 0.01-2.00 m. According to the surface temperature distribution condition of the square billet, the surface center temperature is high, the corner temperature is low, the edge shielding is adopted, the high central cooling strength and the low corner cooling strength are ensured, the surface plane temperature distribution is within +/-20 ℃, and good conditions are provided for the rolling process.
The temperature difference between the surface center of the square billet and the core part can reach 50-400 ℃ through accelerated cooling of the surface of the square billet, conditions are provided for improving the strain value of the core part and refining the grain structure of the core part in the subsequent rolling process, and the defects of looseness, shrinkage cavity and cracks of the core part of the square billet can be welded.
3) Both sides of the mill inlet and outlet are equipped with position and temperature detectors for the billet, see figure 1. The inlet of the rolling mill is provided with a temperature detector for detecting the temperature of the square billet of the current pass before rolling, and the outlet of the rolling mill is provided with a temperature detector for detecting the temperature of the square billet of the current pass after rolling and taking the temperature as the starting temperature of the next pass. The detector can move 0.01-2.00 m in the rolling direction, and is used for meeting the requirement of heat dissipation coefficient detection of different steel grades and avoiding the influence of cooling water on temperature detection. The high-precision online temperature measuring device is combined with a mathematical model for calculating the temperature field, so that the temperature measuring system can simultaneously ensure the precision and the timeliness of the test and the precision and the timeliness of the forecast, and provide accurate reference for making parameters and implementing of the cooling process. The execution process of the square billet strain control is as follows:
(1) the temperature field of the cross section of the square billet is predicted according to the heat history after the continuous casting of the square billet. The strain control prediction model comprises: a square billet temperature prediction model before rolling and a rolled piece strain change prediction model in the rolling process.
(2) And (5) cogging data acquisition. The temperature measurement value of the continuous casting billet is periodically sampled, the temperature sampling frequency is 20 times/second, and a signal is sent to a computer through a PLC (programmable logic controller) for analysis so as to judge whether the billet can be cogging and rolled.
(3) And (4) preprocessing temperature data. Performing data preprocessing according to the principle that the variation amplitude of the sampling temperature at the adjacent moment should not exceed 20%, and if the difference between the sampling temperature at the current moment and the sampling temperature at the previous moment is more than 20%, the sampling temperature at the current moment is not recorded; and then averaging a plurality of groups of data at the same time by taking the second as a unit to finally obtain the temperature distribution curve of the continuous casting billet from the head to the tail.
(4) And judging and executing the conveying mode. Judging the conveying mode of the square billet according to the temperature curve by using a computer; and (3) setting heating or heat supplementing process parameters according to the temperature distribution state of the existing square billet and the requirement of strain control.
(5) Cooling control is performed. And (3) carrying out data sampling on the actual temperature measured value after the continuous casting square billet is subjected to heat supplement, wherein the temperature sampling frequency is 20 times/second, then sending signals into a computer for analysis through a PLC (programmable logic controller), and finally setting and executing cooling process parameters by the computer.
(6) And (5) performing strain control rolling. And (4) performing controlled rolling on the square billet subjected to the composite strain controlled rolling.
4) The present invention is suitable for producing twisted steel, high speed wire, section and band steel.
Compared with the prior square billet rolling deformation technology, the invention has the following advantages:
1) the square billet is subjected to a specific cooling process before rough rolling, so that the square billet presents a large-step temperature distribution from the surface to the core, the deformation resistance is correspondingly in step distribution, the surface resistance is large, the core resistance is small, the deformation extends into the core of the square billet, the deformation is uniform during rolling of the square billet, and a product with uniform structure and performance and few defects is obtained.
2) Because the accelerated cooling is carried out on the surface, the part of the square billet adjacent to the surface is rolled at a lower temperature, the grains can be refined, and the excellent surface property can be obtained.
3) The position of the cooling device is adjustable, the time for the square billet to enter the rolling mill after being cooled can be adjusted, and the accuracy of the rolling temperature point is ensured.
4) The process is suitable for square billets which pass through induction heat compensation, uniform temperature furnace heat compensation and uniform temperature pits, increases the scheduling flexibility between continuous casting and steel rolling processes, reduces the requirement of connection between the processes, and reduces the difficulty of integrated production.
Drawings
FIG. 1 is a process flow diagram of strain control of a directly rolled billet suitable for a billet passing through an induction heat-supplementing, uniform temperature furnace heat-supplementing and uniform temperature pit.
FIG. 2 is a graph of the cross-sectional temperature profile of a billet with and without the use of a strain control process. The point 0 is the center of the cross section of the billet, and shows the temperature distribution of one quarter of the area of the cross section of the billet.
Fig. 3 is a schematic diagram of equivalent strain value position, avoiding the distance of 300mm from the head to the tail of the square billet.
FIG. 4 is a strain diagram of the billet surface and core under two processes during rolling.
Detailed Description
By adopting the square billet strain control process, the strain of the steel core part can be improved by controlling rolling, so that the comprehensive quality of rolled steel is improved.
Specific embodiments of the present invention are further described below.
1) Before a square billet provided by a continuous casting machine enters a conveying roller way, the surface temperature of the square billet is detected firstly, and the heat supplementing and conveying modes of the square billet between the continuous casting and steel rolling processes are selected according to the temperature data measured by a temperature measuring device: induction heat compensation, soaking pit heat compensation or temperature equalization pit heat compensation, judging the final target temperature according to the requirement of strain control, and formulating a heating or heat compensation system.
2) And when the square billet is 1 m away from the front of the rolling mill, a cooling process is established according to the online temperature measurement data, and a cooling device is started.
3) And after cooling, immediately before rolling, judging whether the temperature of the square billet meets the requirement of a strain deformation target or not according to temperature data measured by a temperature measuring device near the inlet and the outlet of the rolling mill. And if the requirement is not met, moving the cooling device, and cooling the blank again until the requirement is met.
4) And taking data detected by a temperature measuring device on the cooling device after the single-pass rolling as a feedback and self-learning basis for controlling the temperature of the next billet.
5) And forecasting the strain state of the rolled piece in each pass in real time, and comparing the strain state with the metallographic structure and the mechanical property which are actually detected.
In this embodiment, a 150 × 150mm HRB400 square continuous casting slab is adopted, and fig. 2 shows a temperature distribution state of a square billet cooled by a strain control process and a temperature distribution state of a uniform temperature of the square billet at 1200 ℃. The positions of the equivalent strain values are shown in fig. 3. FIG. 4 shows a comparison graph of equivalent strain at two line positions I and II in FIG. 3 after the rolled piece passes through the first 5 rough rolling passes, wherein the equivalent strain is increased by 10% within a range of 20mm from the center of the square billet. As can be seen from fig. 4, in the rough rolling stage of the billet, the equivalent strain is greater at the core and near the core of the billet than in the conventional rolling. It is demonstrated that due to the high core temperature and relatively low surface temperature of the billet, the deformation is more permeable to the core than the conventional rolling deformation, thereby increasing the strain deformation of the core.
The mechanical properties of the corresponding steels are shown in Table 1.
| Serial number | Rolling mode | Surface initial rolling temperature, DEG C | Yield strength, MPa | Tensile strength, MPa | Elongation percentage of% |
| 1 | |
1200 | 423 | 562 | 26 |
| 2 | Strain control | 1100 | 430 | 567 | 26 |
| 3 | Strain control | 1000 | 438 | 572 | 27 |
| 4 | Strain control | 900 | 450 | 580 | 29 |
Claims (3)
1. A strain control process for directly rolling a square billet comprises the following process flows: continuous casting → temperature detection → heat compensation and temperature equalization → temperature detection → square billet surface accelerated cooling → controlled rolling → temperature detection → feedback control; the method is characterized in that the technical parameters controlled in the process are as follows:
(1) carrying out accelerated cooling on the square billet, keeping the temperature of the surface center at 750-1200 ℃, and then, rolling the square billet in a rolling mill, wherein the temperature difference between the surface center of the square billet and the core part of the square billet reaches 50-400 ℃;
(2) the method comprises the following steps that accelerated cooling devices are installed at the front and the rear of a rolling mill, the cooling devices are used for cooling square billets through water, the cooling capacity of the square billets is adjusted through the pressure and the flow of a cooling medium, and the pressure of a nozzle is 0.01-2.00 MPa; the cooling capacity is adjustable, and the position of the cooling device is adjustable within a certain range at two sides of the rolling mill, wherein the adjusting range is 0.01-2.00 m; edge shielding is adopted to ensure that the central cooling strength is high and the corner cooling strength is low, so that the surface plane temperature is within +/-20 ℃; the cooling device adopts water as a cooling medium to cool the steel billet
The temperature difference between the surface center of the square billet and the core part reaches 50-400 ℃ through accelerated cooling of the surface of the square billet, conditions are provided for improving the strain value of the core part and refining the grain structure of the core part in the subsequent rolling process, and the defects of looseness, shrinkage cavity and cracks of the core part of the square billet are welded;
(3) the square billet position and temperature detectors are arranged on the two sides of the inlet and the outlet of the rolling mill, and the detectors move 0.01-2.00 m in the rolling direction, so that the requirements of heat dissipation coefficient detection of different steel grades are met, and the influence of water on temperature detection is avoided; the high-precision online temperature measuring device is combined with a mathematical model for calculating the temperature field, so that the temperature measuring system can simultaneously ensure the precision and the timeliness of the test and the precision and the timeliness of the forecast, and provide accurate reference for making parameters and implementing of the cooling process.
2. The strain control process of claim 1, wherein the billet strain control is performed as follows:
(1) the method comprises the following steps of predicting the square billet cross section temperature field according to the heat history after the square billet continuous casting, wherein the strain control prediction model comprises the following steps: a square billet temperature prediction model before rolling and a prediction model of rolled piece strain change in the rolling process;
(2) cogging data acquisition: periodically sampling the temperature measurement value of the continuous casting billet, wherein the temperature sampling frequency is 20 times/second, and sending a signal to a computer through a PLC (programmable logic controller) for analysis so as to judge whether cogging rolling can be performed or not;
(3) temperature data preprocessing: performing data preprocessing according to the principle that the variation amplitude of the sampling temperature at the adjacent moment should not exceed 20%, and when the difference between the sampling temperature at the current moment and the sampling temperature at the previous moment is more than 20%, the sampling temperature at the current moment is not recorded; then averaging a plurality of groups of data at the same time by taking seconds as a unit to finally obtain a temperature distribution curve of the continuous casting billet from the head to the tail;
(4) judging and executing a conveying mode: judging the conveying mode of the square billet according to the temperature curve by using a computer; setting heating or heat supplementing technological parameters according to the temperature distribution state of the existing square billet and combining the requirements of strain control;
(5) executing cooling control: carrying out data sampling on an actual temperature measurement value after continuous casting square billet heat compensation, wherein the temperature sampling frequency is 20 times/second, then sending a signal into a computer through a PLC (programmable logic controller) for analysis, and finally setting and executing cooling process parameters by the computer;
(6) and (3) strain control rolling: and (4) performing controlled rolling on the square billet subjected to the composite strain controlled rolling.
3. The strain control process of claim 1, wherein the product suitable for rolling comprises: rebar, high speed wire, profile, or strip.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1978674A (en) * | 2005-12-07 | 2007-06-13 | 首钢总公司 | Rolling method for solving continuous cast billet shrinkagehole segregation |
| JP2013133503A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method of producing grain-oriented electromagnetic steel sheet |
| CN103556080A (en) * | 2013-10-24 | 2014-02-05 | 钢铁研究总院 | Mechanical property control method for directly rolling long profiles |
| CN105618481A (en) * | 2016-03-15 | 2016-06-01 | 石家庄钢铁有限责任公司 | Equipment and process for conducting protruding roller rolling through continuous casting slab waste heat |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1978674A (en) * | 2005-12-07 | 2007-06-13 | 首钢总公司 | Rolling method for solving continuous cast billet shrinkagehole segregation |
| JP2013133503A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method of producing grain-oriented electromagnetic steel sheet |
| CN103556080A (en) * | 2013-10-24 | 2014-02-05 | 钢铁研究总院 | Mechanical property control method for directly rolling long profiles |
| CN105618481A (en) * | 2016-03-15 | 2016-06-01 | 石家庄钢铁有限责任公司 | Equipment and process for conducting protruding roller rolling through continuous casting slab waste heat |
Non-Patent Citations (1)
| Title |
|---|
| OCr20Mn21Ni2N奥氏体不锈钢锻件组织性能研究;郎宇平 等;《热加工工艺》;20150131;第44卷(第2期);全文 * |
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