Improved Surface Properties of Low-Carbon Steel by Chromizing–Titanizing Coating Using Pack Cementation Process

Abstract

This study investigates the application of chromizing and titanizing coatings on low-carbon steel (LCS) via the pack cementation process, utilizing various compositions, temperatures, and durations. The coating was analyzed using standard techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Vickers hardness testing, to determine their characteristics. The kinetics of the pack chromizing, titanizing, and chromotitanizing of low-carbon steel exhibited parabolic behavior, with the rate constant with increasing temperature. The formed diffusion layers primarily consisted of Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, and Cr1.36Fe0.52, in addition to Fe. The microhardness reached its highest value of 900 HV0.01 Kgf with 48% FeTi, followed by 790 HV0.01 Kgf with 12% FeCr–36% FeTi, 730 HV0.01 Kgf with 24% FeCr–24% FeTi, 680 HV0.01 Kgf with 36% FeCr–12% FeTi, and 560 HV0.01 Kgf with 48% FeCr. The results indicate a significant enhancement in the mechanical properties of low-carbon steel through the coating process. This study confirms that the pack cementation coatings of chromizing, titanizing, and chromotitanizing significantly enhance the surface hardness and mechanical integrity of low-carbon steel. The controlled diffusion process leads to the formation of robust intermetallic layers, and the variation in FeCr and FeTi composition allows for tailored mechanical properties. Additionally, the results suggest that the interplay between Cr and Ti promotes the development of a complex, multilayered microstructure that balances hardness with potential toughness, providing a broad spectrum of industrial applications. This research underscores the versatility of pack cementation as an effective method to engineer advanced coatings, offering a cost-efficient pathway to enhance the performance of low-carbon steel in demanding environments.