LPC versus gas carburizing
What really changes when the process route changes: carbon profile, boost-diffusion sequence, quench route, distortion and validation of the actual component.
Process route first
The comparison is not only atmosphere versus vacuum. LPC changes carbon transfer, boost-diffusion sequencing, chamber pressure, surface reaction conditions and usually the way the process is integrated with quenching.
What must be compared
Case depth and carbon profile, retained austenite and carbide condition, hardness gradient, distortion, surface condition and repeatability should be compared on the actual component geometry.
Qualification
A process substitution is qualified by the component result and its functional requirements. Furnace capability and recipe equivalence are necessary inputs, but they do not replace metallographic and dimensional validation.