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A Closed-loop Control Method of Positive and Negative Feedback for Laminar Cooling

A laminar flow cooling and closed-loop control technology, which is applied in the field of steel rolling cooling control, can solve problems such as low control accuracy, plate shape and performance problems, and unsatisfactory effects, and achieve the effects of improving accuracy, good application prospects, and economic benefits

Active Publication Date: 2016-01-27
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the domestic laminar flow cooling system only uses one positive feedback for real-time control, so the actual cooling temperature of the steel plate deviates greatly from the target temperature, and the actual temperature fluctuations are also large, sometimes as high as ±50 degrees or more, which has a negative impact on the performance of the product. Especially in the process of developing steel grades, excessive cooling temperature fluctuations will affect the development progress of new steel grades, and the production process of new steel grades cannot be quickly stabilized. At the same time, a large number of plates will be generated during the production process Shape and performance problems, greatly increasing the development cost of varieties of steel
Since the laminar flow cooling zone of existing iron and steel plants is generally about 50 meters, some are even longer, and the distance between the outlet pyrometer and the laminar flow inlet is longer, the control accuracy is too low, and the effect is not ideal, resulting in laminar cooling. Most systems only use feedforward control instead of negative feedback control

Method used

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  • A Closed-loop Control Method of Positive and Negative Feedback for Laminar Cooling
  • A Closed-loop Control Method of Positive and Negative Feedback for Laminar Cooling

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The closed-loop control method of laminar flow cooling positive and negative feedback of the present embodiment, its device comprises rolling mill and laminar flow cooling zone, as figure 1 As shown, the laminar flow cooling zone is divided into several sections, the length of each section is 1.5±1 meters (the specific length can be determined according to the field equipment), and the sections are arranged from the back to the front. The first section is the outlet section. The last segment is the entry segment. The laminar flow cooling zone includes the front and rear upper header groups arranged along the output roller table of the rolling mill, and the distance between the two upper header groups is at least 6 meters, and also includes a control system for controlling the upper header groups. A controller and an inlet pyrometer, an intermediate pyrometer and an outlet pyrometer arranged on the laminar cooling zone from front to back and connected with the controller...

Embodiment 2

[0034] The difference between this embodiment and Embodiment 1 is that: figure 2 As shown, in this embodiment, the pyrometer 2 is used to perform the calculation of the feedback 1 and the subsequent feedforward 2, and the pyrometers 1, 3 and 4 do not participate in the above calculation.

Embodiment 3

[0036] In this embodiment, the production of 20mm pipeline steel X65 is taken as an example. The rolling start temperature is 1200°C, the final rolling temperature is 830°C, the moving line speed of the steel plate is 1.5m / s, and the final cooling temperature is 550°C. When the steel plate is rolled for the last bite, the rolling mill triggers the laminar flow cooling zone. At this time, the laminar flow controller initializes the laminar flow cooling zone device and tracking data, and according to the steel type, thickness, final rolling temperature and final cooling target temperature The temperature difference automatically calculates the target temperature of the middle pyrometer, and the target temperature of the middle pyrometer in this embodiment is 600°C. When the steel plate moves below the inlet pyrometer, segment tracking is started, each segment being 1.5 m in length. The controller collects data by section through the inlet pyrometer, and uses the collected inlet ...

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Abstract

The invention relates to a closed-loop control method for positive and negative feedback of laminar cooling, which comprises the following steps: triggering multiple sets of front upper collecting tubes on an inlet section of a laminar cooling area to open after gripping a rolling piece by a rolling mill; initializing a controller; turning a head of the rolling piece into the inlet section; collecting the temperature of the head of the rolling piece and sending to the controller by an inlet pyrometer, thereby performing front feeding calculation 1; backward moving the rolling piece and collecting the temperature of the rolling piece by the middle pyrometer; adopting the temperature of the middle pyrometer and the temperature of the inlet pyrometer to perform front feeding calculation 1 and feedback calculation 1 on the inlet section by the controller, storing an acquired preset value into a section object table; utilizing a tracing function to scan the section object table and finding out all the sections entering the preset collecting tubes, performing the feedback calculation 1 for performing real-time control; when the rolling piece moves to an outlet, collecting the temperature of the rolling piece and sending to the controller by an outlet pyrometer, thereby performing front feeding calculation 2 and feedback calculation 2. According to the closed-loop control method provided by the invention, the precision of the control on the laminar cooling is greatly increased.

Description

technical field [0001] The invention belongs to the technical field of steel rolling cooling control, and in particular relates to a closed-loop control method of laminar flow cooling positive and negative feedback. Background technique [0002] In the steel rolling production process, in order to further improve product quality and increase economic benefits, and obtain high-quality hot-rolled steel, the rolled steel needs to be cooled before entering the coiler after leaving the final stand finishing mill, and the rolled steel is controlled by laminar cooling. The cooling rate is controlled to control the evolution of its microstructure, and then the ideal structure and performance can be obtained. At present, the domestic laminar flow cooling system only uses one positive feedback for real-time control, so the actual cooling temperature of the steel plate deviates greatly from the target temperature, and the actual temperature fluctuations are also large, sometimes as hig...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21B37/76
Inventor 朱鹏举
Owner NANJING IRON & STEEL CO LTD