What is rolling mill automation? This article will express this theme in 3 parts:
1. Main manifestations of automation of steel rolling machinery and equipment
2. Automation and intelligence of the rolling production line
3. Automatic detection and control of rolling mills
1. Main manifestations of automation of steel rolling machinery and equipment
The automation of steel rolling machinery and equipment is mainly manifested in automatic thickness control, automatic width control, plate shape control, planar shape control of medium and heavy plate, dimensional accuracy control of bar and wire rolling mills, hot rolling Microstructure and performance control of steel, automatic elongation control of temper mill and other automation measures, such as automatic quick roll change system for wide strip hot and cold rolling mills, automatic uncoiling at the feed side of the rolling mill, automatic feeding, automatic unloading at the exit side roll, automatic bundling, automatic billet marking machine, etc.
Because as one of the most complicated industrial control processes, the control of modern wide-band steel hot and cold rolling mills has been leading the trend of automatic control technology development. In the 1960s, it was the first to apply electronic computers to large-scale industrial control. A successful example is the control of hot strip rolling mills for wide strips.
Modern steel rolling production process control has the characteristics of multi-variable, strong coupling, deep nonlinearity, and rapidity. The response speed of heavy-duty production equipment in the steel rolling production process is required to be fast (the control cycle requirements of AGC hydraulic cylinder, work roll, and intermediate roll hydraulic bending system can be completed within milliseconds), and the control accuracy is high. For example, the thickness and convexity of the flatness of the strip hot rolling mill are controlled at tens of microns, and the flatness of the modern cold rolling mill is controlled at tens of microns. Edge drop and crown accuracy are controlled within a few microns, and the difference between the same board is controlled within.
Therefore, the high-speed rolling process of plate and strip in modern large-scale hot and cold continuous rolling mills is a process industry production process worthy of the name for ultra-large-scale manufacturing of high-quality goods. The development of rolling machinery and equipment automation has played a huge role in promoting the progress of rolling technology.
The compactness of steel rolling machinery and equipment, on the one hand, is reflected in the compactness of the production equipment structure caused by the rationalization of the steel production process, and on the other hand, in order to ensure the high-precision and high-performance requirements of steel, on the basis of several existing advanced processes and equipment In terms of production equipment, steel rolling production equipment has become a newly developed process, integrated control technology, and newly developed dynamic-orderly operation “interface technology”
The compactness of the device functions with the innovative integrated carrier. The former is because the iron and steel industry is no longer a process separated from unit operations step by step, but a systematic process, and it is also a compact or integrated process. The steel manufacturing process of global steel plants is changing from an intermittent-stop-long process developed in the direction of compactness-quasi-serialization-process shortening.
The evolution of the steel production process since the 1960s shows that the continuous casting process showed a simplification of the function set of the process before, and the subsequent process obviously showed an increasingly simplified integration, compactness, and continuity. The latter is because rolling steel has formed a complete set of high-precision control of shape (size, surface) and high-performance integrated control technology of material control, including online detection control, heat treatment, surface treatment technology, etc.
The main features of controlled rolling and controlled cooling technology are reflected in the use of multi-stand continuous rolling to achieve “one fire” finished products, the use of controlled rolling and controlled cooling technology can realize the control of steel structure and grain, and use waste heat for heat treatment, which simplifies the process flow. The development of continuous rolling and controlled rolling technology has not only greatly improved production efficiency and achieved “one-fire” production, but also changed offline heat treatment to online waste heat treatment, improving product quality and reducing environmental pollution.
2. The rolling production line realizes automation and intelligence
Intelligent and automated rolling will greatly improve the speed and efficiency of production.
In the high-quality bar production workshop of a steel rolling mill that has undergone an intelligent transformation, a 16-meter-long billet is slowly driven out of the heating furnace and enters the next process, which is fully automated. The heating furnace is equipped with a secondary control system, which can more reasonably control gas consumption, oxidation burning loss, improve product quality, and realize automatic control of furnace temperature and pressure; it is equipped with online detection of carbon monoxide and oxygen in the furnace, which can control the air-fuel ratio more reasonably, reduce burning loss.
There are 8 production lines in the entire rolling mill, 4 of which have introduced high-end metallurgical equipment, and are currently the world’s leading steel rolling production lines. The production line is fully automated, including automatic detection, automatic analysis, automatic calculation, and automatic combustion… According to the characteristics of different steel types, it can automatically match the most suitable quality process parameters.
To put it simply, automation is to set the automatic function of the production equipment. Before the rolled billet enters the production line, the roll gap and speed of each rolling mill are set according to the rolling specifications and steel types. The computer calculates and formulates the rolling mill according to the mathematical model. Reasonably press down the procedure, that is to formulate the optimal set value.
Due to the realization of computer automatic setting, the rolling mill has the ability to judge and correct faster than skilled operators, which can improve productivity and product quality, and save manpower. Originally, the entire line was analyzed by manual experience. After using the automated program, the disadvantages of manual operation can be effectively avoided. In the future, only a small number of workers will be retained at the production site for preparation and maintenance. The entire workshop will be built as a “black light factory” to automate driving, collection, etc., and the normal production process will still be maintained after the lights are turned off.
The intelligentization and automation of the entire production also include the high-rod and high-line finished product cross-travelers taking the lead in realizing the position detection of carts, trolleys, and all operating equipment; the double-high-rod cranes realize remote operation and unmanned intelligent control; Online detection of ions, turbidity, and conductivity can realize automatic dosing to ensure controllable water quality; automatic welding (hanging) signage robots have been added to all production lines. “Where robots can be used, robots are used instead of labor, which reduces labor intensity and optimizes the working environment.
3. Automatic detection and control of rolling mills
With the advancement of science and technology, automatic control technology is constantly improving, and people’s attention has shifted from the automatic control technology itself to the results of automatic control. In addition, the continuous advancement of science and technology has also put forward higher requirements for automatic control technology. This requires us to effectively improve the problems existing in the current steel rolling automation, supplemented by online measuring instruments for real-time data monitoring, so as to ensure the efficiency and accuracy of steel rolling, and then promote the steady development of steel enterprises.
At present, the commonly used automatic control functions include steel dimensional accuracy control, automatic plate shape control, automatic temperature control, tissue performance control system, rolling process automatic control system, etc. And with the development of 5G technology and artificial intelligence, steel mills have realized intelligent unmanned production. Professionals only need to operate behind the scenes, and control the start and stop buttons. When problems arise, experts guide the site through remote monitoring. Personnel adjusts and repair equipment.
Of course, it is not blindly pursuing automated high-speed production. To allow the control system to automatically control the size, accurate online detection data is an essential item. Intelligent and automated measuring instruments are installed on the production line to provide real-time data for the control system to achieve various Size control.
The basic automation of the rolling process usually uses programmable controllers to directly control the rolling mill and auxiliary equipment, including speed control, position control, switch control, start logic, rolling stock tracking, etc. The actuators of the control objects mainly include various types of motors, hydraulic cylinders, electromagnets, valves, switches, etc. The control signals come from cold and hot metal detectors, thermometers, force gauges, width gauges, thickness gauges, and shape gauges. , Caliper, Length Measuring Instrument, Straightness Measuring Instrument, etc.
The main functions of steel rolling process control include rolling schedule setting calculation, model self-adaptation, data analysis and processing, quality control, and engineering report generation. Among them, the setting of the rolling schedule has a prominent and important position, because it directly determines how the steel is rolled, and thus has a crucial impact on the shape, dimension accuracy, and microstructure of the product. The post-calculation is to compare the deviation between the model-predicted value and the actual value after the end of the rolling process, which is used for model self-adaptation. This requires the intelligent measuring instrument to have a professional software analysis system, which not only realizes real-time data display and image fitting but also stores various data. Provide sufficient data basis for operators.
The automatic production of steel rolling is inseparable from intelligent detection. At present, our company has also developed a variety of intelligent measuring instruments, such as diameter measuring instruments, the width measuring instruments, thickness measuring instruments, length measuring instruments, temperature measuring instruments, straightness measuring instruments, surface defect measuring instruments, etc. Various measuring instruments can also be combined into one measuring instrument to complete the detection, provide various geometric dimension detection schemes, and bring more accurate and timely data detection for the transformation of steel rolling automation production.