Simulation for Logistics in Steel-making Process of Panzhihua Iron and Steel Corporation

To solve potential scheduling problems in production after renewal of continuous casting process in Vanadium-extracting and Steel-making Plant of Panzhihua Iron and Steel Corporation (PISCO), how to model and simulate logistics system in steel-making processhas been discussed. A series of simulatingtests for logistics system in steel-making processhave been conducted based on inputs of presentsteel-making processof PISCO. In the tests, cases of regular schedule case and cases with repairing converter have also been regarded as essential simulation condition. It has been shown that three casters can not start at same time in order to ensure continuous hot metal supply for casters when three kinds of steel are made. It has also been shown that the simulation system for logistics system in steel-making processis valid and can be used for simulating logisticsin upcoming 100% continuous casting process of PISCO. The better schedule scheme of production and reasonable match of converter-caster in time and capacity can be achieved with the help of using simulation approach.     

Control model for secondary cooling of continuous casting based on compensation temperature of the difference between liquidus and solidus

During continuous casting process, the composition of molten steel often varies with different heats, which leads to the big fluctuation of billet surface temperature when the traditional parameter water control model is applied to control the process. Additionally, it is difficult to keep the temperature at the straightening point of the billet within a reasonable range. Given above consideration, a new control model for secondary cooling of continuous casting based on compensation temperature of the difference between liquidus and solidus has been presented. Meanwhile, the temperature field of the billet is simulated with both the parameter water control model and the new secondary cooling control model, and the results indicate that the new control model for secondary cooling of continuous casting could perform better when it is used to control the surface temperature at straightening points of billet, thereby ensuring the quality of the billet.     

Dynamic Control Arithmetic and Modeling of Secondary Cooling System for ROKOP Billet Continuous Casting

A dynamic control arithmetic and mathematic model of secondary cooling system for ROKOP billet concasting has been developed in view of the changes of casting speed during concasting process and the high fluctuation of surface temperature due to the use of static control method. By means of computer simulation and by comparison between static and dynamic control method, it proves that the latter one is more adaptive to the changes of casting speed, which leads to lower fluctuation of surface temperature.     

Dynamic Control Model for the Secondary Cooling of Slab Casting Based on Neural Networks

A dynamic control model for the secondary cooling of slab casting is presented to reduce the difference between the actual temperature and the goal surface temperature of slab. The model, which is based on the BP neural networks for forecasting the temperature and the fuzzy neural networks for dynamically controlling the water in the secondary cooling in the continuous casting, could timely adjust and allocate the water according to the speed and temperature of slab. A series of tests have been conducted based on inputs of the No. 2 slab caster in a steel plant. It has been shown that the model, which integrate the charateristics of water controlling problem in secondary cooling into the temperature status of slab during the cooling process, can control the water in secondary cooling efficiently and dynamically according to the situation of actual production.     

钢包互用条件及影响因素

为深入研究炼钢厂多台连铸机间钢包产生互用的条件及影响因素,以H炼钢厂的钢包为研究对象,简要解析了钢包运行过程及运行时间。分析了钢包周转次数、周转数与浇铸炉次数之间的关系;运用甘特图模拟出两台连铸机浇次重叠时间为50 min条件下的钢包运行过程。研究表明：钢包产生互用的前提条件为钢包在先停浇连铸机不再承担运输任务,且先停浇连铸机的钢包空包结束时间应在后开浇连铸机钢包的重包开始时间之前。分析了浇次重叠时间对钢包互用的影响,结果表明：浇次重叠时间内连铸机浇铸的钢包数少于围绕连铸机周转的钢包数时才能产生钢包互用。研究了连铸机单炉浇铸时间与钢包周转周期对钢包互用的影响,结果表明：科学控制钢包周转周期和连铸机单炉浇铸时间,合理匹配二者关系,可使浇次最后不需要周转的钢包数增加,提高钢包的互用几率。     

Production Planning Method for Steelmaking-continuous Casting Process Based on Time Backward and Process Simulation

Reasonable production planning effectively ensures smooth operation. According to the analysis of the characteristics of steelmaking-continuous casting production process, a production planning method for steelmaking - continuous casting process based on time backward inference method and process simulation is presented. Production plan meeting certain criteria is rapidly gained by time backward inference method, and is regarded as input of simulation model in steelmaking process. Considering time randomicity in production process and transporting equipment restriction, production plan meeting more restrictive conditions, such as no equipment conflict, continuous casting, and etc, is acquired through simulating. It assures that the plan is carried out in practice. The instance demonstrates the feasibility of the method.     

CCD radiation temperature measurement method for hot continuous casting billet surface

According to the present research status and existing problems of hot continuous billet surface temperature non contact measurement technology, a real time temperature measurement model, which combines two-color(R,G) and monochrome (B) of surface radiation image, is established. The surface image is collected through tricolor charge coupled device (CCD) sensor, at the same time, the temperature dynamic response range of CCD can be improved by controlling integrated time and setting different apertures. Through computer image process technology, multi-point temperature can be measured simultaneously, and 2-D temperature field distribution on continuous casting billet surface can be realized. It is be proved by theory and application that the model and method can provide a theory and technology support for realizing surface temperature field on-line measurement for continuous casting billet.     

Finite Element Method of 3D Stable Heat Conduction of Steel Fluid in Continuous Casting Moulds

The heat transfer of steel fluid in continuous casting mould is a stable process and can be depicted with three-dimensional stable heat conduction equation depending on tension speed. The corresponding finite element equation, including the first, second and third boundary conditions, is deduced out with Galerkin residual method. The coded FEM program is used to analyze the temperature distribution of Q235 steel in continuous billet casting mould. The method proposed is a foundation of thermo-mechanical coupled analysis for the formation of solidified shells and stress in the shells in continuous casting.     

Optimal model on integrated production planning andscheduling of steelmaking and continuous casting process

Considering the uncertainty and complexity of production planning and scheduling in steel making and continuous casting, an optimal simulation model is built. Based on the analysis of the logistics in steelmaking process, the casting plan is regarded as the global goal, and the procedural information is taken into account, as well as the local evolution rule that abstracted from scheduling rule. To simulate transferring of materials in the process, the state of operation sites are updated as a result of the global goals, process information and local rule. The goal directed simulation is carried out based on the self organization evolution mechanism. Finally, an optimal integrated production plan is made by a continuous simulation evolution. A simulation case for eight hours production plan shows that the model is valid and efficient.     

THE STUDY FOR LARGE INCLUSIONS OF STAINLESS STEEL (1Crl8Ni9Ti) DURING CONTINUOUS CASTING

This paper presents the process of stainless steel ( 1Crl8Ni9Ti) in continuous casting,the components and their shapes,origins and distributions of the large inclusions existing in the steel,as well as the influence on its quality. By the observation through a microscope,the structural analysis adopting x-ray examinating instrument and the measunement for the microzone of billet employing the electronic probe.it has been found that the large inclusions of continuous billet mainly originate from the slag-sweeping of the tundisy and mold. There are mostly spherical-slag in addition to Ti(C.N) in the inclusions. The calculations in theory point out that the siO2in the slag can' t change Ti(C,N) into TiO2,however,it can assimilate with Ti(C.N). The large inclusions affect the quality of the steel plate and tube greatly. As a result,this paper proposes the measures of reducing the large inclusions in the steel.     

Numerical Simulation of Temperature Field during the Dissolution-Diffusion Bonding Process to Mending Iron Casting Defects

The common finite element method microcomputer software for simulation of the temperature field is developed by authors. It is used for calculating the temperature field duringthe mending process of iron casting defects by means of the dissolution-diffusion bonding technology. The correctness has been proved by testing results. This software has been used to analyse thecaused of hardness rising in heat effecting zone,and also find out the approach for solving the problem.     

STUDY ON HEAT TRANSFER MATHEMATICAL MODEL BETWEEN BILLETS AND ROLLERS FOR THE SECONDARY COOLING ZONE IN BILLET CONTINUOUS CASTING

A mathematcal model of heat transfer between the billet and the roller for the seeondary cooling zone in billet continuous casting is established. By means of the simulated test,a regres sion relation between the heat flow from the billet into the roller and the surface temperature and cast ing speed and spray water density obtained. The calculated theoretical values for change of surface temperature are in agreement with the measured data, these studies may contribut to the quantitative analysis and the calculation of the heat transfer of the secondary cooling zone.     

The Changes of Underskined Interal Crack of Continuous Casting Billet During Piercing Process

This article studies on the distributional law of underskined internal crack in steel billets of continuous casting billet in additon to the appearance and features of the outer cross crack and outer fold which result from the internal crack during the piercing process.     

Dealing with Thermal Exchange in Temperature Field Simulation in Low Pressure Die-casting Process

The main effort is to develop numerical simulation software of low pressure die casting on Windows platform in Personal Computer, based on the production of aluminum wheel in Die cast wheel manufacture Co. Ltd.. The heat conduction calculation is the basis of solidification simulation. A 3 dimentional model including the refrigeration medium block is set up based on the study of boundary heat exchange. Various calculation method is analyzed for different types of boundary element. A comprehensive calculation model is set up according to practically manipulable parameters in production.     

Advance in Mathematic Model of Solidification Heat Transfer Process in Continuous Casting

The mathematic model of solidification heat transfer process in continuous casting strand is useful for quantitatively analyzing heat transfer in continuous casting process, quality control and process control. The heat transfer in continuous cast strand in crystallizer and secondary cooling zone have been analyzed. The attention has been paid to basic logic and methodology in model building up. Typical methods determing solution condition and parameters for the model have been discussed. Some numerical methods at the present time for solving solidification heat transfer model, such as finite difference method, finite-element method and boundary element, have been investigated comparatively. In the future, working on solidification heat transfer model, which is more practical, and the integration of the control model will play an important role in the development of high efficiency continuous casting technology.     

BOF-caster matching model in steelmaking plant of all plate and strip using precision design principle

Using precise design principle, a multi-objective programming mathematical model of the BOF-Caster matched is established for single production line in the steelmaking plant of all plate and strip, according to the segmentation of steel grade and product specification of product mix. Objectives of the model have less investment, less difference between production capacity of the converter and continuous caster, higher operating rate of converter and higher level of weighted average casting speed. The model is solved by the improved delaminating sequence method. Then, the overall configuration method of BOF-continuous casting in the steelmaking plant is proposed through integrating single production lines. According to the production outline of a new large steel plant, the result of the model shows that the configuration scheme of the steelmaking workshop of the steel plant is a better design scheme.     

Application of Object-oriented FEM in Developing Simulation Software System

Based on object-oriented method, the classes of object-oriented finite element are defined. The finite element program of static, dynamic characteristics and stability analyses for spatial frame structures is developed with c++ object_oriented language which is successfully incorporated into a computer simulation system of derricks. The results of static, dynamic characteristics and stability analysis for the derricks of F320-A and JJ250/42-K types, obtained with the developed system, are consistent with those obtained by a commercial software, which illustrates the correctness of object-oriented FEM and the reliability of the simulation software.     

ROLE OF BaO IN MOLD POWDER USED IN CHNTINUKUS CASTING KF STEEL

In this paper, the role of BaO in mold powder used in continuous casting of steel is studied. The pricipal content of the study is about the effect of BaO on melting temperature, Viscosity, and capacity of absorbing inclusion and glassing of molten mold powder. Experiment results reveal that to add BaO into mold powder can decrease the melting temperature and viscosity, and prevent the formation of high melting point particle and crystallizing of mold powder, suitable BaO content in mold powder is quite helpful to increase the capacity of absorbing inclusion of molten mold powder, and to improve the lubrication effect of molten powder film between mold and billet.     

Design of Simulation System for Logistics in Steel-making Process

A simulation system for logistics in steel-making process has been developed by analyzing the state of logistics in steel plant, integrating the approach of coloured Petri nets with time and queuing network and using object-oriented methodology. The software functions for building-up simulation model, executing simulation, managing simulations, playing demo, analyzing statistics and online help. The objectives and principles of the simulation software have schematically been introduced. At last, the software is visually validated with measured input data of primary logistics in Vanadium-extracting, Steel-making Plant of Panzhihua Iron and Steel Corporation. A Gantt diagram and statistics of simulation case are included in simulation results and can be used to assist decision-making for scheduling in steel-making process.     

Computer Simulation for Analysing the Melting Action of Mould Powders During Continuous Casting

When analysing the performance of casting powders in a specific casting machine, the thickness of liquid slag is a very important parameter. If the liquid slag thickness is not kept above a certain minimum value during the continuous casting operation,the surface and internal quality of the cast products will be jeopardised because lubrication between the strand and the mould is impaired . It is necessary, therefore , to choose the appropriate type of mould powder .In the industrial experiments, it is very difficult and expensive to study this sensitivity by introducing controlled variation in one parameter while keeping all the other constant. Numerical and computer simulation methods are used in the study .They can predict the liquid slag thickness developed above the liquid steel and distribution of the temperature. The sensitivity of the liquid slag thickness to variations can be determined in the material properties of the mould powders.