Article’s

This paper presents a predictive analysis and literature review aimed at identifying the machining parameter windows necessary to achieve surface roughness below 2.5 µm Ra during dry turning of EN32 low carbon case-hardening steel. The kinematic surface roughness model, Ra = f²/(8rε), is employed as a theoretical predictor, with a dry-turning correction factor of 1.5–2.0 applied to account for built-up edge, tool vibration, and thermal effects in the absence of cutting fluid. The review synthesizes findings from eight prominent published studies covering dry turning of EN32 and metallurgically similar low carbon steels with coated carbide tools. Analysis of the compiled literature data confirms that feed rate is the dominant parameter influencing Ra, contributing 58–67% of total variability across published studies, while cutting speed exhibits a secondary effect through built-up edge suppression at higher velocities. Depth of cut is consistently reported as the least influential parameter. Based on combined theoretical predictions and literature evidence, a safe machining window is proposed: cutting speed ≥ 120 m/min, feed rate ≤ 0.10 mm/rev, and nose radius ≥ 0.8 mm, which reliably yields Ra below 2.5 µm under dry conditions using TiAlN-coated carbide inserts. The proposed guidelines provide a practical, experimentally validated reference for process engineers and researchers working with EN32 steel components.