Development And Application Of Multi-function Pilot Hot Rolling Mill

Breaking through the manufacturing technology of high-end products and realizing the process innovation are the key methods to solve the "big but not strong" problem of China's iron and steel industry.Researching and developing advanced pilot equipment and platform are the basis to realize this goal.In this paper,the new generation of multi-function pilot hot rolling mill is developed based on the production practice and combined with the requirements of process innovation.The unique functions,such as roller heating,asynchronous hot rolling and combined controlled cooling are developed to enrich the experimental function on the basis of ensuring the flexible,efficient and high precision.The pilot hot rolling mill provides a R&D platform for the research of hot rolling products and process.New products and process have been developed using the pilot hot rolling mill by a number of iron and steel enterprises and research institutes,achieved good application results.The main contents are as follows:(1)The process flow,technological equipment,automation control system and measuring instrument system are designed and developed for the multi-function pilot hot rolling mill.With the flexible combination of technological equipment,the research methods with the pilot hot rolling mill are enriched,and the studying requirements for the new process and new product of hot plate and strip are satisfied.The roll gap setup strategies for the reversing and non-reversing rolling are proposed.With the new electric-hydraulic gauge control system,the gap setup speed is accelerated without the setup accuracy loss.Aiming at the complex,flexible and changeable characteristics,the tracking system,automatic control system and simulation system are developed for the hot rolling experiment.The stability and achievement rate of hot rolling experiment are increased.(2)The process of heating work roll with hot conduction oil was designed,in order to resolve the problem of low work roll temperature and rapid slab temperature dropping during hot rolling experiment.Also the high rolling temperature requirement for special sample or special process can be satisfied.The roll surface temperature field is studied with the finite element simulation method.The effects of hot oil temperature,ambient temperature,roll diameter and hot oil hole depth on the roll surface temperature field are obtained.With the developed hot oil heating system,the too rapid temperature dropping problem of thin production is resolved,and the higher finish rolling temperature can be reached for the special alloy.(3)The asynchronous rolling function of pilot hot rolling mill is developed,through which shearing deformation is introduced into the hot rolling process,and the deformation efficiency and the deformation permeability are improved.The change rules of rolling force,rolling deformation and head bending in hot asynchronous rolling process are established by finite element simulation analysis.In order to improve the head bending of rolled piece in hot asynchronous rolling process,horizontal shifting system of lower roll is developed and head bending control strategy for rolling pieces in asynchronous rolling process is proposed,finally,the problem of excessive head bending of rolled piece in hot asynchronous rolling process is solved effectively.(4)The combined controlled cooling system with ultra-fast cooling as core is developed.The cooling temperature control model is established and the self-learning method of heat transfer coefficient is given.The integrated control strategy is put forward to solve the strong coupling between the UFC system pressure and the header flow.The control strategy of feedforward setting plus feedback fine tuning is applied to control the UFC system pressure and the header flow respectively.The pressure feedforward control and the flow feedforward control are applied simultaneously.After the system is stable,the pressure feedback control is used as the main control method,the pressure feedback and the flow feedback control are alternately carried out.The dead zone control and fuzzy PID adaptive control are introduced in the feedback control system.The corresponding control algorithm is given to compensate the return and the dead zone of the regulating valve.All these control strategies ensure the system pressure and the header flow fast,stable controlled and with high precision.The control precision of the final cooling temperature is improved,and the research and development demands of the new generation of TMCP technology are satisfied.(5)The new generation of multi-function pilot hot rolling mill is developed based on the research results in this paper,in which advanced three level computer control system is adopted,the system is equipped with high-precision automatic gauge control system and experimental process tracking system,fully automatic experiment is realized.The special functions such as roll heating,hot asynchronous rolling and combined control cooling with ultra-fast cooling as core provide more experimental means for research and development.This pilot hot rolling mill has been successfully extended to nearly twenty iron and steel enterprises and scientific research institutes such as ShouGang group,ShaGang group,TISCO,HBIS,ANSTEEL,CSC and so on,in which a good application results have been achieved,and it provides a reliable research method for innovation of hot rolling process and senior variety development.