Abstract
The thermal conditions in the molten pool during the laser surface melting of ductile cast iron EN-GJS-700-2 were estimated by using infrared thermography and thermocouple measurements. The thermal data were then correlated with the microstructure of the melted zone. Additionally, the thermodynamic calculations of a Fe-C-Si alloy system were performed to predict the solidification path of the melted zone. It was found that increasing the cooling rate during solidification of the refined ledeburite eutectic but also suppressed the martensitic transformation. A continuous network of plate-like secondary cementite precipitates and nanometric spherical precipitates of tertiary cementite were observed in regions of primary and eutectic austenite. The solidification of the melted zone terminated with the Liquid → γ-Fe + Fe3C + Fe8Si2C reaction. The hardness of the melted zone was affected by both the fraction of the retained austenite and the morphology of the ledeburite eutectic.
Highlights
Over the past three decades, considerable research has been devoted to enhancing the wear resistance of different grades of cast iron via laser surface modification methods
Substrate material (SM) specimens with dimensions of 25 × 60 × 10 mm were ground to an average roughness (Ra ) of approx. 0.5 μm
The laser processing trials were carried out by using an experimental stand that was equipped with a Rofin-Sinar DL 020 2.0 kW continuous-wave high-power direct diode laser
Summary
Over the past three decades, considerable research has been devoted to enhancing the wear resistance of different grades of cast iron via laser surface modification methods. Most reported works have focused on shaping the microstructure, and wear properties, of surface layers by using laser surface melting (LSM) [1,2,3,4,5]. This process involves rapid solidification and cooling, and it provides a unique opportunity to synthesize non-equilibrium structures [6,7]. To optimize the wear properties of the working surface of the components that are made of a particular cast iron grade via LSM, it is necessary to comprehensively analyze the microstructure evolution in the processed surface layers under different solidification conditions. Since DCI is finding use in a growing range of Materials 2020, 13, 1174; doi:10.3390/ma13051174 www.mdpi.com/journal/materials
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
