Based On The Steps Outside The Ring Of Slab Rolling Forming Process Numerical Simulation

Ring parts with outer stepped such as bearing rings and flanges are the keymechanical Parts in equipment manufacturing industry and industrial areas. Withthe rapidly development of engineering machinery, aviation, aerospace，defense-related science and technology，the demand of the ring parts with outerstepped is increasing. Under the goal of the construction of aresource-conserving society, how to reduce cost, improve efficiency，saveenergy and reduce emission became the problem to be solved in ring parts withouter stepped production. A new casting-rolling compound forming processtechnology has many merits such as short process flow, high efficiency, savingenergy and materials. Supporting by the Key Program of National NaturalScience Foundation of China (NO.51135007), this paper mainly study theforming process of hot rolling which is the key link of the program, aiming atstudy the variation law of appearance size precision and internal microstructurewhen the ring is directly rolled by annular casting blank, and achieving thedouble purpose of controlling the shape and controlling the properties of the ring.At last, this paper will provide theoretical foundation for the forming process ofhot rolling of annular casting blank, also it will lay the foundation for the furtherdevelopment of the casting-rolling compound precision forming process.As an example, an outer ring of large slewing bearing was researched inthis paper, based on the theoretical analysis, DEFORM software was used tosimulate the hot rolling process of ring with outer stepped, which material is42CrMo steel (a commonly used material for hot rolling of bearing), and theresults were analyzed, the influence of parameters and physical dimension onthe rolling process were researched. The following conclusions are obtained:Firstly,the ovality of excircle and absolute spread amount of step surfacesharply increases and then steadily decreases until stability, dynamicrecrystallization occurrence from the outer and inner to the core,the part ofsmall ring has a higher volume fraction of dynamic recrystallization and asmaller grain size; Secondly, a bigger feed velocity of the idle roller, a larger rolling rate, a smaller rate of axial height of big-small parts have a smallerabsolute spread amount of step surface, a higher volume fraction of dynamicrecrystallization and a smaller grain size.