Effect of Laser Traverse Speed on the Metallurgical Properties of Fe-Cr-Si Clads for Austenitic Stainless Steel Using Directed Energy Deposition

This study investigated the microstructural and compositional behavior of Fe-Cr-Si clads produced in stainless steel (STS) 316 L with a decreased laser traverse speed using directed energy deposition (DED). The substrate of all specimens was mostly composed of austenite, while the clad region consisted of the delta-ferrite, martensite, and a small amount of retained austenite. The reduced heat input by increasing the laser traverse speed resulted in decreased dilution of the Ni component and the substrate's unmixed zone, resulting in a gradual decrease (16-1%) in the face-centered cubic (FCC: austenite) phase of the clad region. In addition, in the clad region composed of body-centered cubic (BCC), the fraction of martensite decreased, but the fraction of the delta-ferrite increased by decreasing the heat input. The reason for this was that dense martensite was formed in the entire clad region owing to a sufficient cooling rate for phase transformation and dilution of the Ni component in the 12 mm/s specimen with the highest heat input. Therefore, to predict the corrosion and wear characteristics of the Fe-Cr-Si multilayer clad manufactured in STS316L, the formation of martensite by the dilution of the Ni component should be sufficiently considered.

Automated summary

This study investigated the microstructural and compositional behavior of Fe-Cr-Si clads produced in stainless steel 316 L with a reduced laser traverse speed using directed energy deposition. The results showed that increasing the laser traverse speed led to decreased dilution of the Ni component and the substrate's unmixed zone, resulting in a gradual decrease in the austenite phase of the clad region. Additionally, decreasing the heat input resulted in a decrease in the martensite fraction and an increase in the delta-ferrite fraction in the body-centered cubic clad region.