Bar companies have formed a consensus on the construction of intelligent production lines. However, bar production lines still have problems such as low data collection efficiency, difficult material tracking, weak quality control, poor quality of finished products, chaotic storage areas, and high costs.
By adding key technologies such as billet surface inspection, billet headless welding, controlled rolling and controlled cooling, automatic diameter measurement, high-speed cooling bed, finishing system transformation, industrial robots, unmanned crane transformation, warehouse management system and other key technologies, these innovative technologies have been organically integrated. It runs through and integrates into the process, which can meet the needs of the production line for product accuracy, production output, and remote centralized control. There have been representative application cases in many bar factories.
At present, the mechanical equipment of the bar production line has little differentiation and low intelligence, and remote centralized control cannot be performed. Intelligent centralized control is needed to improve the reliability of equipment control and strengthen electrical interconnection and automation control levels, so as to reduce the equipment failure rate and maintain the stability of the production line. production order. Specifically, the following problems should be solved:
(1) The billet has not passed the quality inspection before entering the furnace, and it is easy to cause defective billets to mix in, affecting production and product quality; the surface inspection instrument for small and medium-sized bars can only be used for the surface inspection of bars with a small rolling speed, and the instrument is backward, the error of the detection result is large.
(2) At present, there are two forms of endless rolling of rods and wires, one is welding type, and the other is casting rolling type. The former also needs to solve the speed matching with the heating furnace and the roughing mill, the deburring effect, and the stable operation of the equipment; the latter involves the steelmaking and continuous casting system, which is more difficult to realize.
(3) Although controlled rolling and controlled cooling device are used, it does not have a self-learning function when changing varieties and does not achieve precise control. The temperature deviation is large, resulting in unstable product quality.
(4) Insufficient application of calliper, manual sampling and calliper measurement, great potential safety hazards, lagging behind in finding and handling problems, often leading to out-of-tolerance products.
(5) Various control rooms are distributed throughout the production line, occupying a large number of personnel, and the control rooms need to be combined to realize remote centralized control. The functions of the basic automation system need to be subdivided, and the control accuracy needs to be improved urgently. The lack of production big data systems and feed-forward adjustment models requires the production line itself to have the ability to self-adjust, shorten the time for changing varieties, and system fault-tolerant response.
(6) The cooling bed equipment has low control precision, slow braking, many accidents, and insufficient capacity. In addition, the cold shearing capacity is poorly matched with the cooling bed and inspection bench capacity, and the steel yield and cut-to-length rate are low.
(7) The inspection bench has a low degree of intelligence, and most of them use manual counting, which has low efficiency, poor accuracy, and high labour costs. Insufficient holding force often leads to poor bundling quality, low efficiency, and less investment in listing and industrial robots for the collection device of the test bench, which needs further improvement.
(8) The crane is old, the warehouse management system is incomplete, there are many operators and managers, the palletizing area is chaotic, the efficiency of the warehouse is low, the labour intensity is high, and there is no warehouse management such as an electronic fence, grey bus, delivery scanning, and recording. systems and facilities.
If the above problems are solved, a new intelligent control system for steel rolling will be formed, and intelligent steel rolling will be implemented to increase the product pass rate by more than 1%, which can meet the needs of the bar production line for product accuracy, production output, and remote centralized control.
The bar production line has the following intelligent technology applications:
1. Selection and development of surface detectors
The surface defects of blanks and bars can be detected by an infrared surface flaw detection unit, but the detection speed is only 1 m/s at most. The detection of surface defects is connected with the rolling production line through network communication, the surface defects of the rolled piece can be detected and can be removed or retained according to the process requirements to improve the inherent quality of the rolled piece.
The round bar surface detection system can carry out casting number, square removal, automatic length measurement and automatic identification of special-shaped billet for the billet, and can also detect the surface defects of the bar, and the detectable running speed is 0-20 m/s. A unique green light source is used to assist the industrial camera to scan the moving bar at full width. According to the different reflection characteristics of light in different areas on the surface of the bar, the feature information extraction, analysis, and pattern recognition of the captured pictures are carried out, and the defects are identified and recorded. system.
2. Selection of endless rolling technology
Italian Danieli Company has developed welding-type endless rolling technology, which is greatly affected by welding carbon equivalent requirements, so the applicable range of steel grades is narrow; while continuous casting-rolling type endless rolling technology is applicable to the range of steel grades More broadly, in theory, the steel grades with no problem in continuous casting can basically realize continuous casting and rolling.
The welded endless rolling technology has the flexibility to stop at any time, so the requirements for the rolling line and subsequent finishing equipment are relatively loose. By using the relocation of the heating furnace to expand the production and the adjustment of the slag flushing groove of the furnace roller table, the heating problem can be solved. The problem of insufficient distance from the furnace to the roughing mill is suitable for the reconstruction of old factories. The continuous casting and rolling endless rolling technology are more suitable for new production lines, especially for the current capacity replacement, relocation and transformation projects, and the construction of ultra-short process bar production lines should be given priority. Endless rolling can increase production capacity, enable enterprises to obtain direct economic benefits, and is conducive to energy saving and emission reduction.
3. Intelligent selection of controlled rolling and cooling equipment
When producing bearing steel, spring steel, gear steel, steel for construction machinery and other special steel types that require controlled rolling and cooling, the use of thermomechanical controlled rolling and controlled cooling technology can reduce the off-line heat treatment process for some products, and control the surface and core. The uniformity of grain size improves the consistency of the whole length size. For example, the rolling line adopts the controlled rolling and controlled cooling technology controlled by the thermometer, infrared detector and computer system to suppress the high-temperature phase transformation, refine the structure, and improve the strength and strength of the steel. plasticity.
Process automation level online control system (level L2) and mathematical models mainly include: establishing a steel process database, establishing a temperature control mathematical model suitable for steel types, and controlling the cooling process parameters of the rolled piece according to the process temperature target of the steel type According to the different process requirements of controlled cooling, different control modes are selected. According to the requirements of the finished product, the process planning and design are completed through special software, and the obtained rolling piece temperature is self-study and self-study within the specified range by using the mathematical model of controlled cooling. adapt. When working in a semi-automatic state, the parameters of the database table can be called for setting.
4. Selection of online measurement system
The use of online detection technology can improve the detection speed, solve the problems of missed detection, slow detection speed, and potential safety hazards in manual sampling inspection, and is also beneficial to improve product precision control. The online detector can be directly installed on the production line, and use measurement technology to perform real-time detection and feedback on the rolled piece, so as to better guide the process adjustment. The diameter measuring instrument can be set according to different varieties, and communicate with the secondary system of the production line. It can display relevant feedback information in real-time on the on-site display screen, and make timely adjustments, thereby improving product quality and yield.
5. Add automation equipment to the inspection bench
(1) Selection of automatic counting device.
The fully automatic bar counter is usually suitable for products with specifications above 8 mm and can complete the automatic counting and bundling of bars. Its characteristics are high system reliability, strong anti-interference, and high-definition images of a full range of counting processes the data signal recording system can carry out all-around automatic tracking of the counting process.
The online counting and separating system uses machine vision technology to identify and locate the steel bars online, and automatically stitches the images to finally realize the automatic counting function. Realize automatic steel division.
Based on the principle of image recognition, the whole bundle re-inspection counter takes the image of the whole bundle end face and uploads it to the computer. The computer calculates through the model algorithm, marks the ends in the image, and calculates the number of bundles, which is consistent with the setting The number of counts can be checked, automatic and manual photos can be realized, the number of bundles can be set arbitrarily, and the light alarm prompts when errors occur, which can be manually corrected. The equipment is installed about 1.1 m behind the weighing platform to achieve the mutual verification of quality and the number of bales and reduce the wrong bale rate.
(2) Selection of bar weighing and binding machine system and OEM and welding robots.
The automatic bar binding system is to complete the collection of the bars from the inspection bench into bundles and transports them to the binding position through the roller table. After the bars are bundled into cylindrical shapes by the former, they are automatically controlled by several sets of wires arranged in series. The binding machine is used to complete the full-length binding of the bars, and the cylindrical bars are transported to the work area for weighing, re-inspection and listing of the finished products through the roller table.
At present, most of the automatic bundling and automatic weighing can be completed, but the listing is still mainly manual listing, and there are also steel belt strapping machines, which spray the bar information on the steel belt through a printer and use double identification of words and barcodes to facilitate tracking.
Automatic welding and labelling robots have been gradually used. According to the process characteristics of the welding label operation in the finished product area, the pre-printed labels are welded and pressed to the end of the bar or the surface of the bar. This is based on intelligent vision. Technology, image recognition software drives industrial robots to replace manual tasks, realizes data storage of production line control system and metering system, realizes the automation of the entire process of welding and OEM and achieves the purpose of intelligent listing.
6. Multi-layer network communication
Through the functional subdivision of the basic automation system and the substantial improvement of control accuracy, it is supplemented by a production big data system and a feed-forward adjustment model. The program controller communicates with the motor drive system of the production line through the Profibus network, and the finished product flying shear program controller communicates with the front main rolling line and the rear cooling bed area program controller through the GENIUS network, realizing the front-to-back connection. Realize the communication with the upper computer and touch screen set on the production line through industrial Ethernet, and complete the accumulation, transmission and analysis of big data under the cooperation of multi-layer networks, so that the production line can be endowed with AI functions and cooperate with the current gradually mature 5G network. It can enable rolling enterprises to realize remote centralized control in different places and further improve production efficiency.
7. Unmanned crane and intelligent warehouse management technology
Existing production lines and finished product warehouses equipped with cranes can be intelligently transformed, such as replacing frequency-regulated motors, sliding wires, gray busbars, detection devices, vehicle scanning platforms, crane machine rooms and control rooms, etc. According to the requirements of the existing intelligent warehouse management, the fixed material frame stacking yard is managed in partitions, and the positions of cars and trains to be delivered are positioned, so that multiple overhead cranes have the learning capabilities of automatic avoidance, continuous work, and automatic acceleration and deceleration. The spreader such as the electromagnetic crane of the car undertakes the task of intelligent unloading and loading to achieve efficient transportation. Each bar is stacked in a fixed position on the shelf, and each bar lifted by the electromagnetic crane is also required to be positioned and managed so that the whole process of the bar can be tracked.
To sum up, these innovative technologies are integrated organically and integrated into the process to form a new intelligent control system for steel rolling. Realize the unmanned operation and intelligent logistics system of the entire production line, which can ultimately improve product competitiveness and meet the bar production line’s requirements for product accuracy, production output, remote centralized control and another intelligent steel rolling, and gradually realize low cost, high precision, and flexibility. Minimized and less humanized production has broad application prospects and high use value. There is a long way to go to explore and practice the transformation and development of intelligent manufacturing. It is necessary to combine and apply new technologies emerging in the industry at any time in order to build the correct model of intelligent manufacturing for steel enterprises in the future.