Effects of Laser Hardening Process Parameters on Hardness Profile of 4340 Steel Spline—An Experimental Approach

• Main Authors: Noureddine Barka, Sasan Sattarpanah Karganroudi, Rachid Fakir, Patrick Thibeault, Vincent Blériot Feujofack Kemda
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Coatings
• Subjects: AISI 4340 steel; analysis of variances; case depth; laser hardening; splined shaft; experimental analyses
• Online Access: https://www.mdpi.com/2079-6412/10/4/342

This study displays the effect of laser surface hardening parameters on the hardness profile (case depth) of a splined shaft made of AISI 4340 steel. The approach is mainly based on experimental tests wherein the hardness profile of laser hardened splines is acquired using micro-hardness measurements. These results are then evaluated with statistical analysis (ANOVA) to determine the principal effect and the contributions of each parameter in the laser hardening process. Using empirical correlations, the case depth of splined shaft at tip and root of spline’s teeth is also estimated and verified with measured data. The obtained results were then used to study the sensitivity of the measured case depths according to the evolution of laser process parameters and geometrical factors. The feasibility and efficiency of the proposed approach lead to a reliable statistical model in which the hardness profile of the spline is estimated with respect to its specific geometry.