Process prediction and control by an empirical model based on equivalent diffusion for carburizing or carbonitriding processes

An empirical model has been developed by studying the rate of case formation for various materials. This model uses the relationship observed between material hardenability and case rate. Material hardenability is based on a modified version of critical ideal diameter by using the normal steel composition with the exception of holding carbon constant at 0.40% (a rough estimation of the carbon level required for effective case depth). It predicts the level of diffusion needed to meet specification requirements and adjust parameters to optimize process design and resulting product characteristics. Inputs needed for process control are the equivalent diffusion number and a material classification. All times, temperatures, carbon set points and level off parameters are automatically downloaded to the equipment for process execution.