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Article Citation - WoS: 4Citation - Scopus: 4Simulation of Through-Hardening of Sae 52100 Steel Bearings - Part Ii: Validation at Industrial Scale(Wiley-v C H verlag Gmbh, 2016) Evcil, G. E.; Mustak, O.; Simsir, C.In this study, the material dataset presented in part I of this article is validated at industrial scale in batch through-hardening of bearing races. The material dataset acquired is implemented in a commercial heat treatment simulation software. Heat transfer coefficients for the oil and salt bath are determined by using a commercial standard quench probe. Zone temperatures and transfer times of the roller-belt furnace are measured directly from the system. Through-hardening of inner ring (IR) of 6813 bearing in oil and salt bath is simulated considering most of the industrial details. Finally, predicted dimensional changes are compared with the coordinate measurement results and a good agreement is achieved. It is concluded that determined material and process data, idealizations and simulation procedure can be considered "validated" for further improvement of the industrial process.Article Citation - WoS: 13Citation - Scopus: 19Multiscale Modeling of Tempering of Aisi H13 Hot-Work Tool Steel - Part 2: Coupling Predicted Mechanical Properties With Fem Simulations(Elsevier Science Bv, 2016) Eser, A.; Broeckmann, C.; Simsir, C.Simulation of austenitization and quenching of steel using the Finite Element Method (FEM) is nowadays a common tool to predict residual stresses and deformations during these processes. However the simulation of tempering, which determines the final residual stresses and distortions has been often neglected or performed in a purely phenomenological and highly simplified way. The objective of this study is to precisely predict the relaxation of internal stresses during tempering, taking explicitly into account the evolution of the microstructure. Mechanical properties which determine the relaxation of stress; namely the drop of the yield stress and the creep mechanism are the key factors for the success of the simulation. These mechanical parameters can be determined experimentally for a specific tempering temperature. However tempering temperature for most steels varies for each industrial application in order to adjust the desired hardness-toughness relation. Consequently, experimentally measurement of decisive mechanical properties which determine the amount of stress relaxation for each tempering temperature is very costly. Therefore, these material parameters were simulated from physically based material models with coupled microstructural simulations in the first part of this two-part investigation. In this part of the study, the simulated mechanical properties will be coupled with the FEM simulations using "Abaqus (R)", in order to simulate the stress relaxation during the tempering process of a thick-walled workpiece made of hot-work tool steel AISI H13 (DIN 1.2344, X40CrMoV5-1). Utilizing this methodology, different tempering conditions (soaking time, tempering temperature) can be considered in the model to predict the stress relaxation in macroscopic scale. (C) 2015 Elsevier B.V. All rights reserved.Article Citation - WoS: 8Citation - Scopus: 10Simulation of Through-Hardening of Sae 52100 Steel Bearings - Part I: Determination of Material Properties(Wiley-v C H verlag Gmbh, 2016) Mustak, O.; Evcil, G. E.; Simsir, C.A complete material dataset for the simulation of through-hardening of SAE 52100 (DIN/EN 100Cr6, JIS SUJ2) steel was derived by a combination of experimental and theoretical/computational methods. In the experimental part, alpha/quenching and deformation dilatometry techniques are combined with density measurements, X-Ray diffraction, optical and scanning electron microscopy to determine temperature and phase dependent transformation kinetics parameters, thermal and transformation strains, flow curves and the transformation plasticity parameter. Thermal properties such as thermal conductivity, specific heat and enthalpy and elastic properties are acquired by thermodynamics based material property calculation method using a commercial software. For most of the material properties, the results were in good agreement with the literature, while the minor discrepancies are discussed considering the raw material, equipment used, testing and evaluation procedure. In Part II of this article, compiled material data is validated successfully in an industrial oil and salt-bath quenching of bearing races.
