Abstract
Surface treatments characterized by rapid heating and cooling (e.g. laser hardening) can induce very steep residual stress gradients in the direct vicinity of the area being treated. These gradients cannot be characterized with sufficient accuracy by means of the classical sin2Ψ approach applying angle-dispersive X-ray diffraction. This can be mainly attributed to limitations of the material removal method. In order to resolve residual stress gradients in these regions without affecting the residual stress equilibrium, another angle-dispersive approach, i.e. the universal plot method, can be used. A novel combination of the two approaches (sin2Ψ and universal plot) is introduced in the present work. Prevailing limits with respect to profiles as a function of depth can be overcome and, thus, high-resolution surface layer characterization is enabled. The data obtained are discussed comprehensively in comparison with results elaborated by energy-dispersive X-ray diffraction measurements.
Highlights
Laser surface hardening is a highly localized heat treatment procedure characterized by the evolution of superior compressive residual stress states in the hardened material layer in the direct vicinity of the surface
Steep compressive residual stress (CRS) gradients induced by laser hardening of micro-alloyed steel in the direct vicinity of the surface (
This opens up new research opportunities in the field of highresolution residual stress analysis
Summary
Laser surface hardening is a highly localized heat treatment procedure characterized by the evolution of superior compressive residual stress states in the hardened material layer in the direct vicinity of the surface. The process is based on a localized phase transformation promoted by heating only the surface layer to austenitization level, followed by rapid self-quenching to eventually form martensite. This local phase transformation is accompanied by the evolution of a characteristic compressive residual stress (CRS) profile (Davis, 2002; Kostov et al, 2013). In order to characterize the surface layer comprehensively, various characterization techniques can be used (Schajer, 2013; Withers & Bhadeshia, 2001) Thermal treatments, such as laser surface hardening and high-frequency impulse hardening (induction hardening), both characterized by extremely high heating and cooling rates, can lead to extremely steep residual stress gradients within the immediate surface region (Bleck & Moeller, 2017; Dewi et al, 2019). The evolution of residual stresses in laser-hardened surface layers has been considered in many cases
Sign-in/Register to view highlights & summary 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.
