Comparison of Rare Earth Refinement in 4130 and HY100

Solidification based grain refinement has gained wide interest by both researchers and industry. This method provides a route for in processes where thermomechanical approaches are ineffective. Prior research into 4130 HY100 found very different responses when rare earth additions were made. The was effectively refined while showed no response. cause of this difference not determined. presented paper examined heats with silicide or EGR additions. Characterization included macrostructure examination, mechanical testing, thermal analysis, electron microscopy. Refinement observed only the treated corresponded to an increase peritectic temperature. had changes solidification reactions. Rare containing inclusions similar compositions heats. These appear be good fit austenite on data. It proposed that unresponsiveness due strong segregation nickel before alloy. Nickel promotes austenite, its may provide stronger driving force formation than energy barrier reduction caused presence inclusions.