Research On Large Scale Electroslag Casting Equipment And Key Technology

At present,special casting equipment industry in China has weak capacity of independent development,and the specialized supporting system is not yet mature.Especially the large electroslag casting equipment is simple in function and backward in control means.It can not meet the needs of the casting process of large and complex castings,and restricts the application and popularization of this advanced molding technology in our country.The project has applied research on key issues such as furnace design,energy saving short net design,microcomputer control and monitoring system for large scale electroslag furnace.Through the determination of the process parameters,such as the amount of slag added,the power supply system,the depth of the electrode embedded in the slag pool and the cooling conditions during the melting and casting process of large and thick ratio castings,a set of system design technology for the melting and casting of the complex and thick proportion of the castings with the complex and thick ratio of the electroslag casting is obtained.By studying the heat treatment process of Q345C material with large width to thickness ratio,the mechanical properties of such castings can meet the national standard of forgings.The project has obtained the following main research results:(1)In view of the casting and casting process requirements of large complex castings,the 6 degrees of freedom of the mechanical transmission are realized by adopting the matching mode of the furnace body and the mobile trolley.Using the characteristics of T type AC transformer,the neutral tap connection mode is adopted to solve the compatibility of single phase casting and bipolar series casting.At the same time,the three-phase power supply balance of electric slag furnace is realized,and the balance of three phase power supply is greater than 80%.(2)The electric slag furnace power supply system adopts the 27 level voltage regulation switch,the adjustable voltage range is 70-140V,and the voltage difference of each stage is 2V,which meets the requirements of the complex casting.The two output of the transformer uses copper row connection and parallel arrangement;the connection of copper and arm adopts large cross section water cooled soft cable,reducing resistance and reactance to reduce the loss of short network pressure drop and improving the service life of short network.(3)The key process design methods such as arc forming process,electrode structure and power supply parameters are obtained.The design idea and calculation method of uniform filling coefficient are put forward and the problem of cold separation on the surface of super large width thickness ratio casting is effectively solved.Through the composition control and heat treatment optimization of Q345C typical large and thick ratio castings,the mechanical properties of the castings are finally reached to the same material forging and rolling standard(GB/T 1591-94),and the optimum normalizing process is 920?.