Scenario-driven material selection for powder metallurgy gear components under drawing-derived constraints

Powder metallurgy (PM) gear components produced by press-and-sinter processing must satisfy drawing-derived constraints for sintered density, tensile strength, surface hardness, and metallurgical state. When material substitution is required, selecting admissible candidates from a standardized grade library becomes a multidimensional decision problem whose priorities vary with application severity. This study proposes a framework comprising three stages: (1) feasibility screening against mandatory drawing constraints, (2) rule-based analytic hierarchy process (AHP) weight derivation from documented engineering signals, and (3) technique for order preference by similarity to ideal solution (TOPSIS) ranking with structured sensitivity analysis and Pareto-efficiency assessment. The framework was applied to eight component positions across light-duty and heavy-duty gearboxes using eleven MPIF Standard 35 grades evaluated against five criteria. Screening reduced the candidate pool from 11 to 3–10 per part. The AHP produced cost-dominant weights for the light-duty scenario and mechanically dominant weights for the heavy-duty scenario. TOPSIS identified FL-4405 and FLN2-4405 as the leading candidates for the respective scenarios; both were Pareto-efficient. Top-three membership remained unchanged across the sensitivity tests. The framework provides a reproducible, auditable approach that links weight derivation transparently to documented engineering requirements.