Keywords distributed temperature control, upper computer, lower computer, communication protocol, heating furnace.
The Minmetals Southwestern Aluminum Group Co., Ltd. rolling plant pusher-type heating furnace is a key auxiliary equipment for hot rolling lines introduced from the United States. It is the first large-scale natural gas aluminum ingot heating furnace in China's aluminum processing industry.
Its temperature control technology is of chronological level. After many years of operation and use, it gradually exposed many problems through the relay conversion galvanic signal upstream and downstream, resulting in a complex system structure, anti-jamming and poor reliability 2) temperature control intelligent instrument using Hornyway Seoul company-type smart meters, its internal relay misuse of false alarms occur from time to time, affecting the temperature uniformity of the original system does not have reliable monitoring of the temperature control process, the lack of effective management of process and control parameters.
Due to the existence of these problems, the need for large-scale production of hot-rolling lines cannot be met.
Therefore, in order to increase the automatic control performance of the entire propelled heating furnace to a higher level and achieve the purpose of expanding the production scale and reaching the standard of production, we have fully utilized the new achievements of modern computer management knowledge and distributed temperature control technology, and successfully developed a simple operation and maintenance convenience. Full-featured, reliable, safe, high-operability, superior man-machine interface, and temperature uniformity of the pusher-type heating furnace computer distributed temperature control system.
The project's on-site implementation is divided into two steps. The first step is to change the original natural gas combustion relay control system to control. The second step is to change the original temperature-controlled intelligent instrument to a computer workstation with strong management functions.
The system has great practical value and economic value, and can provide valuable experience for domestic design and reconstruction of similar temperature control systems for heating furnaces.
The main technical parameters of the system are Jing Hong and Deng Gaochao.
Southwest Aluminium Group) Limited expensive company Qingting Factory, Equipment Department Chongqing Xipeng Date 1 Furnace Temperature Range Metal Temperature Uniformity One Temperature Difference Upper Set Temperature Punching Computer and Control System Aluminum Processing Downstream Set Temperature One Furnace Gas Over Temperature Alarm Temperature Upstream and Downstream Set Temperature System Composition and Communication System Components The propelled heating furnace distributed temperature control system is composed of upper computer workstations, which are hereinafter abbreviated as upper computer and lower programmable logic controller, hereinafter referred to as lower computer, and are connected through a communication port.
The upper computer completes the management function of the system, and the lower computer completes the control function of the system.
The system consists of R&D workstations as shown in the figure.
One by one.
One by one.
Sit and twist the upstream and downstream thermoelectric quotients. Cong Jun Longwei Sanyiyi (The lower position diagram system consists of O ù ù ù ù The positioner is in the existing combustion control system Mitsubishi series expansion rack, adding two channels of galvanic signal signal input Module and a serial communication module for communication with the host computer.
The upper computer, including a research and development workstation, with a touch screen input communication card communication settings communication card port settings and initialization, completed by the host computer user software package a communication level.
Its setting is baud rate data bit parity check no stop bit flow control interrupt request input/output range A communication module A communication module protocol DIP switch setting as shown.
Among them, the communication speed setting is a setting for the communication station number. The switch is set for the system. The station number is the mode setting switch. The system is set to the specified protocol type. The mode is one-by-one. Switch design Ritual graphic design The lower computer control program implements the logic control of the original relay and the temperature signal acquisition and processing functions of the smart instrument through the lower computer software, and completes the size fire and the upstream and downstream temperature conversions, real-time detection of temperature and other signs through Communication is passed to the host computer.
The temperature control program and the conversion program are shown in the figure. The upstream and downstream temperature conversion of the original system is handled by the thermocouple signal passing through separate lines and relays to enter the smart meter to complete the upstream and downstream temperature conversion.
In this way, since the thermocouple is a millivolt-level voltage signal, the contact error of the line error and the relay contact will directly affect the accuracy of the collected temperature of the smart meter, so that the accuracy of the temperature control cannot be guaranteed, which seriously affects the heating quality of the aluminum ingot. .
Therefore, we canceled the separation of lines and relays. The thermocouple signal acquisition plug-in of the lower machine with amplification and cold junction compensation function directly collected the plastic signal of the thermocouple aluminum processing computer and control system and processed it according to the rotation direction of the circulation fan. Upstream and downstream temperature conversions.
After such treatment, the line and relay contact errors are avoided and the temperature sampling accuracy is improved.
Heating starts heating time.
Upstream/downstream Judo Conversion fire control Second Downstream Ju Ju Upstream Ju Judu Down Judging Judging Upstream Ju Ju Duo Up Host Upstream Retreat Register Sign Up Downstream Ju Ju Register Diagram Temperature Control Program Flowchart Diagram Software Upstream and Downstream Temperatures Conversion flow chart PC management program PC management program is a self-developed Chinese language interface running in the Chinese management software structure shown in Figure Requirement of the hardware environment is the above personal computer, a color display, the above keyboard and mouse or touch screen operation.
Software development uses software packages.
Its excellent visual programming environment and powerful data processing functions provide powerful guarantees for the user program's good interface and data management.
The management functions mainly include furnace dynamic process and temperature setting management simulation instrument and real-time temperature control curve management temperature control history curve management gas ratio adjustment management temperature error correction management curve and report printing management digital and simulation monitoring management communication management. l[The main program information sequence sequence rate adjustment sub-order sequence function words and pseudo-monitoring sub-strings sequence sequence subcriterion and print-printing error rate Grass area shape Xinzi strange body posture a twisting furnace Ni order diagram Host computer management program structure chart Chong computer and control system aluminum processing Through this software, you can intuitively and quickly understand the advancement furnace temperature control system operating status and process parameters, can also be The digital and analog monitoring functions can track the furnace operation and equipment operation status in real time. The user can also analyze the product quality and equipment faults according to the curve and printed report data to obtain a solution to the problem.
In the temperature setting process, the operation of repeatedly setting the temperature in each smart meter is cancelled, and the upper computer touch operation is performed, and uniform or single-area input of the constant temperature in each area reduces the labor intensity of the operator.
The user can also correct the thermocouple error compensation wire and system errors easily and quickly by using the error correction function to ensure the sampling accuracy.
The adjustment of the mixture ratio of natural gas and air is the key to ensure the accuracy of the temperature control of the heating furnace and the uniformity of the furnace temperature.
Regulators accurately adjust the proportion of gas, can safely and freely control the size of the fire and the district temperature, and make natural gas can be completely burned.
1) Using thermocouple signal acquisition with lower amplifier and cold junction compensation function to directly collect thermocouple signal, and realize automatic conversion of upstream and downstream temperatures by software, which can greatly reduce loss of thermocouple signal on the line and components, and improve temperature control. Accuracy and heating quality of aluminum ingots.
Push-type heating furnace computer distributed temperature control system user software, user interface is superior, just through the screen prompts, you can easily operate freely.
Its excellent process control data dynamic tracking and storage capabilities provide powerful guarantees for the development of sophisticated products.
Zhao Yigui, Wang Gecheng.
Programming Guide.
Beijing Central Radio and TV University Press, Guo Xunhua, Feng Tiejun.
Master Beijing Post Press.
Wang Ke Li School's conclusion is followed by the page.) Through the above-mentioned tests and analysis, it can be seen that it is due to the presence of high hydrogen sodium content in aluminum-bismuth alloy large ingots and the presence of metal inclusions such as flux inclusions and coarse intermetallic compounds. The microcrack source causes stress concentration, which causes the fracture strength of the alloy to decrease greatly. During the hot rolling process, due to the action of external force, local deformation occurs in the grain boundary, which promotes the accelerated propagation of the crack source when the local deformation stress exceeds the plastic deformation. At the limit, the brittle fracture occurs along the crystal, and its macroscopic appearance is delamination and crazing cracking.
In order to prevent aluminum-beryllium alloy from cracking during hot rolling, it is recommended to adopt the following measures to improve the smelting and casting process, improve the quality of the ingot, and reduce or eliminate metallurgical defects in the ingot.
There are data difficulties indicating that during the melting process of the aluminum-antimony alloy, the proper amount of cylinder gas is used to protect the melt, and the melt is subjected to sufficient vacuum degassing before casting. The melt transferred to the crystallizer should be effectively sealed off from the air and protected with flux. When the flux is used to make up the flux protection layer in the mold as much as possible, the flux is remelted, and impurities such as calcium and strontium in the crystal water and the flux are sufficiently removed, and the porosity or pores of the alloy can be reduced.
In the casting process, when the flux is used to protect, the melt is evenly and smoothly conveyed to the crystallizer to keep the casting process stable, and the fluctuation of the metal level in the mold is avoided, and the non-metallic inclusions can be effectively reduced.
Increasing the grade of raw materials and flux refining can reduce the sodium content.
The ingot is heated sufficiently and uniformly to minimize the inhomogeneity of grain boundaries and intragranular structure.
Reasonably adjust the amount of pass reduction and try to ensure that the billet is uniformly deformed, especially in the deformed area of ​​the billet.
Price 6 two magic.
æ›° æ›° å£ å£ æ›° 二 汪 Wang Lingyun, Liu Jingan.
Practical metal plastic forming physical metallurgy Chongqing science and technology literature publishing house Chongqing Branch, Cheng Yuanming edited aluminum alloy defects.
Harbin Heilongjiang Science and Technology Press, Fan Yunqiang and so on.
Common defects in aluminum-antimony alloy casting.
Special Metals and Non-ferrous Alloys, edited by Li
Product Description
PTFE Rod
•Material: 100% virgin PTFE, no recycle.
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SPECIFICATION:
Diameter(mm) Dia. Tolerance(mm) Length(mm) Length Tolerance(mm)
4~9 +0.48~0.58 1000/2000 +10.0
10~50 +1.1~1.6 1000/2000
55~200 +2.0~5.0 1000/2000
4ft,or as request
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Item Unit Value
Gravity g/cm3 2.10-2.30
Tensile Strength MPa more than 14
Elongation Break % more than 140
PTFE Rod
PTFE Rod,Teflon Rod Stock,Teflon Rod,White PTFE Rod
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