Development of a Process Signature for Manufacturing Processes with Thermal Loads FRIEDHELM FRERICHS, HEINER MEYER, REBECCA STRUNK, BENJAMIN KOLKWITZ, and JEREMY EPP The newly proposed concept of Process Signatures enables the comparison of seemingly different manufacturing processes via a process-independent approach based on the analysis of the loading condition and resulting material modification. This contribution compares the recently published results, based on numerically achieved data for the development of Process Signatures for sole surface and volume heatings without phase transformations, with the experimental data. The numerical approach applies the moving heat source theory in combination with energetic quantities. The external thermal loadings of both processes were characterized by the resulting temperature development, which correlates with a change in the residual stress state. The numerical investigations show that surface and volume heatings are interchangeable for certain parameter regimes regarding the changes in the residual stress state. Mainly, temperature gradients and thermal diffusion are responsible for the considered modifications. The applied surface- and volume-heating models are used in shallow cut grinding and induction heating, respectively. The comparison of numerical and experimental data reveals similarities, but also some systematic deviations of the residual stresses at the surface. The evaluation and final discussion support the assertion for very fast stress relaxation processes within the subsurface region. A consequence would be that the stress relaxation processes, which are not yet included in the numerical models, must be included in the Process Signatures for sole thermal impacts. https://doi.org/10.1007/s11661-018-4719-8 Ó The Minerals, Metals & Materials Society and ASM International 2018 I. INTRODUCTION THE importance of manufacturing processes on the functional performance of components is generally known. This is especially true for finishing processes, such as grinding or hard turning, which affect the functional performance by changing the workpiece surface layer properties, e.g., residual stress state, microstructure, and hardness. These problems have been topics of scientific work for the past several decades. Field et al. [1] reported on the surface integrity of machined components. Recently, Habschied et al. [2] studied this subject, considering the generation of residual stresses. Jawahir et al. [3] reported on a round robin test, in which the participants were requested to achieve a compressive surface residual stress of  200 MPa by means of different machining methods. Due to the widely scattering results of that test, the authors stated that even under laboratory conditions, a controlled generation of surface layer properties is not state of the art in machining processes. It is assumed that this knowledge gap is the result of a process-oriented view that has prevailed in scientific analyses, in which the resulting workpiece material modifications are predominantly correlated with machining parameters and/or process quantities. Nev- ertheless, the process-oriented view is still state of the art, like the works of Liang et al. [4] and Lazoglu et al., [5] in which models for residual stress predictions have been proposed on the basis of process quantities. However, as a consequence, the validity of the process-oriented findings is limited. The internal material loads, i.e., stresses, strains, strain gradients, temperatures, and temperature gradients, which actually lead to observable material modifications, are difficult to determine or even know at all. A material-oriented view, which focuses on the mechanisms leading to workpiece material modifications by manufacturing processes, has the aim to bridge knowledge gap. A new study from Brinksmeier et al. [6] introduced the concept of Process Signatures, intended to correlate material modifications with internal FRIEDHELM FRERICHS, HEINER MEYER, REBECCA STRUNK, BENJAMIN KOLKWITZ, and JEREMY EPP are with the Leibniz Institute for Materials Engineering-IWT, Badgasteiner Strasse 3, D28359 Bremen, Germany. Contact e-mail: frerichs@iwt-bremen.de Manuscript submitted November 14, 2017. METALLURGICAL AND MATERIALS TRANSACTIONS A