The Research And Production On Compound Roll Of Austempered Ductile Iron

Roll is indispensable important unit in the rolling mill and requests high strength and hardness in epidermis and excellent ductility and toughness in interior．The traditional roll usually produces with white cast iron,high c~ome casting iron and ductile iron,but the roll produced with traditional process has call not satisfied the specific needs of modemization production,with the development of metallurgical industry towards more greatness,high speed and automation．Austempered ductile iron has excellent synthetic mechanical properties of high strength and hardness and excellent ductility and toughness,but the production of austempered ductile iron mostly uses austempering process at nOW．In order to overcome disadvantages of austempering,bring down consumption of energy,ameliorate labor condition and improve synthetic mechanical properties of the roll,we research the production of the compound roll of austempered ductile iron by adding appropriate alloy elements in as-cast condition．We Can find out the optimal production process of the compound roll of austempered ductile iron by improving component and structure,thermal field simulation using computer and experimental production．The research results indicate that the compound roll of austempered ductile iron have excellent synthetic mechanical properties of high strength and hardness and excellent ductility and toughness and the optimal chemical component of the production,the appropriate additions of Ni,Mo,Cu and the optimal heat treatment technology respectively are C3．7％,Si2．4％,Mn~<0．3％,S≤0．05％,P≤0．05％,ferrosilicon containing barium 0．3％(the addition of inoculation),Ni4％,MoO．6％,Cu0．5％and coolness in the air after keeping l hour at 250"C．Alloy elements and their additions and tempering heat treatment technology have not obvious influence on graphite morphology of the compound roll of austempered ductile iron,but they have important effect on the marx structure and the additional alloy elements homogeneously distribute in the matrix structure and the marx structure is mixed structure of bainite,retained austenite and rare matensite．The compound roll of austempered ductile iron Can obtain the optimal synthetic mechanical properties when the proportion between bainite and retained austenite is 4．5:1．It is found that the compound roll of austempered ductile iron does't generate shrinkage and dispersed shrinkage by thermal field simulation,SO we can steadily produce the compound roll of austempered ductile iron．...