Research and application of rod and wire controlled rolling and controlled cooling technology

Abstract.：In the control process of rod and wire production, it must make application analysis of the two aspects of controlled rolling and controlled cooling technology, pay attention to the control content in the control key process, and make an overall understanding of its application. By analyzing the research process of rod and wire controlled rolling and controlled cooling technology, aiming at its actual efficiency in control aspect, improving the production quality is taken as its basis, and doing a good job in the wide application, really improving the current application process of rod and wire controlled rolling technology, and improving the subsequent production efficiency.

keyword：Rod and wire; Controlled rolling; Controlled cooling

In the context of China's development, steel production capacity continues to increase, and its raw materials and prices have gradually shown a rising state. In order to improve the overall competitiveness of the steel market, it is necessary to further increase the research on the production cost and quality of steel. As for the control content of rod and wire, the hardware can be handled as a whole in the rolling process to control its finished product effect. In the control, in the control cooling process to improve the strength of steel, improve the low temperature toughness of steel. Play the role of each quantized alloy, save alloy. Simplify the production process and make control.
 

The so-called controlled rolling is to optimize its heating temperature during the control process. In the process of hot rolling conditions and artificial control, the subsequent cooling content is controlled, so as to achieve a kind of process of ideal crystal construction. Based on the control of bars, based on the application of cooling control automation technology, it is mainly through the automatic control system as its carrier, and to achieve the automatic development of the control process. The key technology of controlling the rolling process is that in the rolling process, it is often implemented in a lower range. The grain refinement of the ferrite is achieved by low temperature impurities, which makes the chromite ferrite content identical. At the same time, it can also achieve normalizing and quenching, improve its strength and toughness. Controlling the rolling content can make a large amount of ferrite form in austenite and make consistent construction of corresponding crystals. Effectively refine the grain size of ferrite, and the control point of this series of operations is to reduce the heating temperature as much as possible, and filter the austenite system at the beginning of rolling. The optimal development of the rolling process in the intermediate temperature zone, during the repeated crystallization process, resulting in the austenite unit in terms of crystal deformation and boundary conditions to increase ferrite formation, which can reasonably control the alloy composition of the steel and ensure its production quality.

Controlled cooling refers to a content of strengthening refinement, which quickly changes the relevant temperature of its ferrite and austenite after the controlled rolling is made to achieve a certain degree of operation content and achieve the refinement of the phase change group. At the same time, in the process of cold industrial development, its strength will gradually increase, and finally obtain the ideal toughness and strength. According to the principle of boiling and the principle of cutting water impact, it can be cooled in the process of heat transfer on the surface of the rod line body. Under the basic form of heat transfer, it can be divided into boiling heat transfer, non-boiling heat transfer and unidirectional forced convection heat transfer. Based on its heat transfer process, the cooling water makes contact with the steel plate and floats on the surface of the steel plate. This will rapidly transpiration and gasification, in the cooling sluice and the interface will form a layer of gas film, and the heat transfer coefficient between the plug-in is small, and the cylinder identity of the heat transfer coefficient, which is reflected in the rolling itself will form the corresponding air grinding layer. The layer is evenly cooled by the use of air flow.

In the process of adjusting the bar rolling process, the deformation of the process parameters is more difficult, and most of them need to have the corresponding void to make a determination. And after several changes to determine its deformation, so as to meet the actual requirements of solid control, in the process of small birch material, can only control the temperature of various rolling mills to make control. By controlling the rolling temperature, the deformation side can meet certain requirements. Based on control and technology application, it can produce steel with good toughness. In addition, it can also do a good job of decarbonization and simplification, heat treatment, for example, for some non-tempered steel, the use of rolling and with controlled cooling process, can form some high-strength standard components. Such a raw material has a positive effect on the annealing process and the adjustment content, which can effectively save the return time and is favored by users. According to the control rolling of small rod and wire mill, it mainly includes two kinds of deformation rolling. First of all, the two-stage deformation system is analyzed. Based on the crystal shape and spermatophyte growth content of austenite, a large number of deformed austenite is obtained during the transformation process of austenite to ferrite, and then the spermatizing treatment is made. After the phase transformation, fine ferrite grains can be obtained. In the process of the development of the two-stage deformation system, it will further crystallize and the impurities will be transformed. The process can replicate the corresponding crystals in the austenite crystal zone, realize the common rolling between the two, and have certain substructural characteristics after the phase change.

In the process of rod and wire production, some of the products rolled out must be changed from the original high temperature state to normal temperature state. The temperature cooling rate of the rod and wire after rolling also determines its mechanical properties and the amount of surface oxide sheet iron, which also has a profound impact on product quality control. After the completion of rolling, how to complete the quality control is one of the key links. Controlled cooling technology is to control the microstructure and properties of steel according to different cooling speeds after controlled rolling. In the thickening controlled cooling process, it will not reduce the toughness of the rolled part itself, which will further improve the strength and toughness of the steel itself. This condition also determines the subsequent construction content, and in the control process, the phase transition relationship is analyzed. Based on the content of phase transformation control and the structure of phase transformation products, the organic combination was made. Select the appropriate construction process to use, the controlled cooling process of steel includes three heat treatment stages. The first is the quenching stage, which is that after the bar leaves the middle mill, it is immediately entered into the cooling water tank and formed the firing line. In the tempering stage, the bar leaves the water cooler and is rapidly heated to rapidly expand the surface, so that the surface clusters are tempered. In the natural cooling stage, the rolling control is carried out on the cold bed.

According to the composition of bar rolling automation system, it is also divided into three levels of control system from top to bottom. The first automatic control system for the process control machine, according to the process control machine. In the rolling tracking process, the appropriate storage content is selected based on the rolling specification programming. In the process of raw material management, the billet management, contract management, product management, parameter setting, rolling line equipment, state monitoring and other conditions are analyzed to form the corresponding production report. And combined with the dairy mill and the company erp system to make communication. Secondly, the basic automation and heating furnace control system. This will be controlled according to its fuel air string and cross control content, and it will be hydraulic and smooth during the cold feeding and hot charging and hot feeding process control. At the same time, based on the whole control content, looping control, micro-tensioning, control, space in the rolling area including Zaki expulsion, chain condition and medium reaction are made. Management is based on the liquefaction, conduction and lubrication process of the entire rolling line, the height of the looper is detected during the transmission and instrument control process, and the temperature is measured based on its layout.

In the continuous rolling unit, because the rolling section is too large, it is not easy to use some looping, and some micro tension is generally used to make control. The application of micro-tension control has good application value. In the process of micro-tension control, the initial value point reading method and initial value current method are based on small continuous rolling units. It can be established by existing conditions to form a solid rotation between the two mills, and any change is caused by the uncertain speed relationship. For example, for the steel moment of DN frame, the moment of n-1 frame is considered to be the ideal rolling moment. Therefore, the initial current method is used, and it must be kept closed at all times during the micro-tension control process. The change content of rolling temperature friction force and elongation is analyzed, which has become the key point of rolling control. In the process of rolling temperature control, management is done based on its condition content.

In the aspect of loop content control, the main function of the loop is to check and adjust the speed relationship between adjacent frames to achieve tension-free rolling control. The control quantity can be accurately grasped in the control process of frame bending and arc cutting. This also improves the accuracy of subsequent frame dimensions based on the tension between the frames. Control of its breadth content, according to the general management process, the control of the rack table is developed by the looping control content. Including two aspects of the problem, the first need to control the problem of its sleeve steel, in the process of checking the height of the loop, the rolling content is compared, and the deviation is found and then adjusted, so as to do a good job of frame speed control. Finally complete the customization of the setting, and achieve the second flow balance in its frame. In the verification and adjustment process, the whole steel is stabilized, and the rolled part is also formed in the rolling process of free arc, and there is no tension.
 

Rolling control technology is an important symbol of rod and wire technology development, through the introduction of key models, it is very important to analyze the rolling parts control technology, which is also the focus of current control development. In the process of the development of thermal rolling technology, it can also reach the international advanced level. It is necessary to increase the research process of controlled cooling technology after rolling and analyze it according to the actual demand of different steels. Meet the construction process, and according to its construction status management. According to the actual construction requirements, in the domestic and foreign industrial comprehensive process out of their own rolling control cold technology, improve the production efficiency.