Research On The Technology Of The Third Spray Cooling For Horizontal Continuous Casting Of Cast Iron

Cast iron profiles are divided into two categories:pearlite matrix and ferrite matrix.Pearlite matrix cast iron profiles have higher mechanical properties(such as strength,etc.)than ferrite matrix cast iron profiles,and account for the vast majority of practical applications.They are often referred to as high-strength cast iron profiles.In order to obtain high-strength cast iron profiles,so far.there are two main methods that can be adopted at home and abroad:one is to add a large amount of alloying elements Cu,Mn,Ni,Mo,etc.,so that the matrix structure in the continuous casting process is directly converted to pearl The other is to normalize the as-cast profiles under the premise of adding a small amount of alloying elements,and then transform the matrix structure into pearlite through further heat treatment.Although both methods can obtain high-strength cast iron profiles,but because the former method needs to add a large amount of alloying elements(including some precious alloy elements),the latter method requires a lot of power consumption,under normal circumstances,the cost increase is more than 30%,they will greatly increase the production cost of the profile and reduce Technical and economic benefits of cast iron profiles.Based on the production characteristics of cast iron profiles,this paper proposes the technical idea of the third spray cooling in the process of horizontal continuous casting of cast iron profiles,exploring a method that does not add a large number of precious alloy elements or heat treatment,but can still obtain high-strength cast iron profiles new method.In this paper,?93mm and ?120mm horizontal continuous casting ductile iron profiles LZQT450-12 are taken as the research object,relying on the self-developed the third spray cooling experimental device,the effect of the third spray cooling process parameters on the structure and performance of cast iron profiles is explored.Research indicates:(1)Preliminary design and manufacture of a set of three-stage horizontal continuous casting cast iron spray cooling device,mainly including the water inlet pipe,the water spray water bag,the water bag support frame and the bottom water tank.Different process parameters can be controlled by adjusting the opening and closing degree of the water valve.The device has a simple structure and reliable operation,and can better meet the actual production needs(2)The structure and properties of different parts of ?93mm and ?120mm before the third spray cooling ductile iron profiles are found,and it is found that the change trend of the two rod diameter ductile iron profiles from the surface to the center is the same,that is,the graphite morphology becomes worse and the content of pearlite increased,the interlayer spacing becomes larger,and the mechanical properties become worse(3)The horizontal continuous casting ductile iron profile can significantly change the pearlite content of the cast iron profile and its lamellar spacing after the third spray cooling,which can effectively improve the mechanical properties of the cast iron profile(4)Comparing the effects of different the third spray cooling process parameters on the structure and properties of the ductile iron profile,it is found that when the third spray cooling process parameters are:three water bags+adjust water valve fully open+water bag spacing 250mm,comprehensive mechanical properties can be obtained relatively well Ductile iron profiles(5)When the best the third spray cooling process,comparing the influence of the profile diameter on the three spray cooling effects,it was found that the smaller the experimental profile diameter,the deeper the sprayed layer,the more uniform the cross-sectional micro structure performance,and the better the effect.