The mechanical properties and the near surface microstructure of the high-manganese twinning-induced plasticity (TWIP) steel X40MnCrAl19-2 have been investigated after deep rolling at high (200 ${}^{\circ }\mathrm{C}$ ), room and cryogenic temperature using different deep rolling forces. Uniaxial tensile tests reveal an increase in yield strength from 400 MPa to 550 MPa due to surface treatment. The fatigue behavior of selected conditions was analyzed and correlated to the prevailing microstructure leading to an increased number of cycles to failure after deep rolling. Deep rolling itself leads to high compressive residual stresses with a stress maximum of about 800 MPa in the subsurface volume characterized by the highest Hertzian pressure and increased hardness up to a distance to the surface of approximately 1 $\mathrm{m}$ $\mathrm{m}$ with a maximum hardness of 475 HV0.1. Due to more pronounced plastic deformation, maximum compressive residual stresses are obtained upon high-temperature deep rolling. In contrast, lowest compressive residual stresses prevail after cryogenic deep rolling. Electron backscatter diffraction (EBSD) measurements reveal the development of twins in the near surface area independently of the deep rolling temperature, indicating that the temperature of the high-temperature deep rolling process was too low to prevent twinning. Furthermore, deep rolling at cryogenic temperature leads to a solid–solid phase transformation promoting martensite. This leads to inferior fatigue behavior especially at higher loads caused by premature crack initiation. At relatively low loads, all tested conditions show marginal differences in terms of number of cycles to failure.

Kurzfassung: Mechanische Oberflächenbehandlungen, beispielsweise das Festwalzen, spielen in der technischen Praxis eine bedeutende Rolle und tragen wesentlich zur Steigerung der Zuverlässigkeit hochbeanspruchter Komponenten bei. In einer Reihe von Fällen wurde gezeigt, dass eine Erhöhung der Prozesstemperatur die Wirksamkeit der Verfahren noch steigert, weil dies zu einer besseren Stabilisierung der eingebrachten Druckeigenspannungen führt. Eine wesentliche Voraussetzung zur Einführung dieser Verfahren in die Praxis ist allerdings, dass insgesamt effiziente und möglichst kurze Prozesse resultieren, bei denen die erzielbaren Eigenschaftsverbesserungen in einer ausgewogenen Relation zum Mehraufwand im Vergleich mit konventionellen Prozessen stehen. In der vorliegenden Arbeit wird gezeigt, dass die Prozessintegration von induktiver Wärmebehandlung und Festwalzen in diesem Zusammenhang vielversprechend ist und es werden erste Versuchsergebnisse vorgestellt.

For industrial applications efficient and short processes are essential, justifying the increased complexity of deep rolling treatments at elevated temperature. For this purpose, the direct integration of deep rolling manufacturing steps in heat treatment processes is a promising strategy. Combining inductive heat treatment with deep rolling leads to encouraging results concerning near surface material states as well as resulting fatigue strengths. Different process concepts are introduced and discussed. Characteristic results of near surface microstructures and residual stress states produced in this way for steels SAE 1045 and SAE 4140 are presented. In addition, the consequences of the material states and the microstructures on cyclic deformation behaviour and fatigue strength are outlined. The integrated system introduced allows the flexible application of appropriate process parameters, the analysis of their effects on the fatigue behaviour and the determination of optimised process conditions.