The Stress Calculation Of Dry Brick Lining Of Blast Furnace Hearth

Blast furnace is an important equipment for steel production enterprises,steel production is the overall process of the most important equipment,and blast furnace longevity for the promotion of economic efficiency plays an important role.The life of the hearth and the safety of its structure are the major factors limiting the generation of blast furnace service.Hearth lining erosion not only includes oxidation and dissolution of high temperature molten iron and lining,erosion of alkali metals and zinc,thermal load and thermal stress,but also the erosion and mechanical stress from molten iron etc.Among them,the hot metal circulation and thermal stress is considered to be a key factor in the destruction of the hearth brick lining.In recent years,dry brick lining of brick(including brick joint)+ filler + shell(sprinkler cooling in outer surface)in hearth structure has been applied to blast furnace,but for the study of mechanical properties of dry brick lining is rarely reported in hearth.In addition,in the previous research of structural mechanics model of blast furnace hearth,the thermal properties of materials are usually fixed value to simplify the calculation,which results in decreased accuracy.In order to obtain accurate calculation in this paper,the thermal properties of hearth filler material of dry brick lining was determined by experiment,combined with heat transfer,elastic-plastic mechanics etc,the thermodynamic properties of dry brick lining of blast furnace hearth were analyzed by numerical simulation.The specific contents are as follows.(1)Variations of the compressive strength,the thermal conductivity and linear expansion coefficient of the ramming material of filler layer were analyzed by experiments with the forming pressure and the heat preservation temperature.The change rule of compressive strength&the forming pressure,thermal conductivity&temperature and linear expansion coefficient&temperature were obtained,represented with intuitive curve.(2)Based on the principle of thermal elastic mechanics,the thermal elastic multi contact surface nonlinear model of dry brick lining of blast furnace hearth was established.The mechanical properties of dry brick hearth lining after expansion under heat were analyzed by designing corresponding finite element parametric program,including change rule of the maximum circumferential stress,brick joint maximum opening,the maximum radial tensile stress and its position of the lining with the hot surface temperature etc.In condition,the compressive strength of the ramming material of filler layer was checked.Finally,the numerical example was used to verify the correctness and availability of the program.(3)Based on the change rules that have been obtained about brick joint closed length and the furnace shell circumferential stress change with the width of the brick joint and other parameters,the sensitivity analysis that the effect of several important factors to the circumferential stress of lining hot surface as based on the response surface method was carried out,and the quantitative impact of various random variables on the circumferential stress of lining hot surface was acquired.Strictly controlling the factors that great influence can effectively prevent the lining crack due to excessive stress,avoid the further erosion and prolong the service life of blast furnace.