The Thermo-coupled Analysis On Bending And Cooling Of Medium Steel Plate

In the manufacture of automobile,tractor,locomotive,chemistry and boilerinstallation,the part by bending plate material have a large proportion.usually, for thesheet material which thickness is between 5 and 20 ㎜, the bending technique of it ismade under high temperature; when the capability of shop equipment be not enough,even if the bending of thin sheet material is carried out under high temperature too;inaddition, the intense cold work hardening,warp and flaw can be came into being whenthe shaping of the special steel that contain chromium be made under roomtemperature,so the process be made under high temperature. The thermal contraction is made of two part:one is the △t which is in the directionof thickness, another is the △R which is in the direction of radial direction.The △t canbe acquired by reckonning in the thermal contraction ratio. However,the are a strikingdissimilarity between the△R and the real value and induce the mold disablement. The thermal stress and thermal deform which be brought up by the heterogeneouscooling induce the different expansion on each point ,which is the intrinsic factor ofthermal contraction.There are many factor which influence on homogeneousness duringcooling.On the premise of same type of cooling,the shape,surface quality,temperatureof the part is all influence on the thermal deform.In order to acquire the thermalcontraction value of the plate during cooling and offer the proper value for modifyingmold,The rule of thermal contraction have to be analyzed during cooling. Based on combination of simulation analysis with FEM software and theoreticalresearch, This paper completely have analyzed the major factor which influence on thethermal contraction during bending and cooling of plate and educed the rule betweenthese factors and thermal contraction.Finally,the mathematical expression be given outby curve fitting the simulation result base on the polynomial least square method. In order to modify mold properly depending on the thermal contraction,this paperhave deduced the profile curve function of the mold.according as the displacementvector relation of the finite element node during the plate bending and cooling.Thebending mold can be designed easily and exactly. The are many factor which affect the thermal contraction and the correspondingfunction relation are intricate.In order to use easily,this paper have developed softwareby way of programming with these function. II...