Abstract A stress analysis for a Hertzian contact of ball on groove is presented. The subsurface stresses, the equivalent stresses and the effect of residual stresses are shown by diagrams. Based on this analysis the requirements for materials applied in rolling element bearings are derived. The basic properties of the bearing steels, the predominantly used materials for rolling element bearing components are described. The influence of the austenitizing temperature, method of quenching and tempering temperature on the material properties is shown on the example of the bearing steel 100CrMnSi6-4. It is demonstrated how the requirements derived by these results can be fulfilled by modern equipment for industrial heat treating. It is also shown, to which extent residual stresses can be induced by different quenching procedures and that bainitic hardening can result in advantages especially for bearing applications.
{"title":"Material Stress and Heat Treatment of Rolling Bearing Steels","authors":"O. Beer","doi":"10.1515/htm-2022-1003","DOIUrl":"https://doi.org/10.1515/htm-2022-1003","url":null,"abstract":"Abstract A stress analysis for a Hertzian contact of ball on groove is presented. The subsurface stresses, the equivalent stresses and the effect of residual stresses are shown by diagrams. Based on this analysis the requirements for materials applied in rolling element bearings are derived. The basic properties of the bearing steels, the predominantly used materials for rolling element bearing components are described. The influence of the austenitizing temperature, method of quenching and tempering temperature on the material properties is shown on the example of the bearing steel 100CrMnSi6-4. It is demonstrated how the requirements derived by these results can be fulfilled by modern equipment for industrial heat treating. It is also shown, to which extent residual stresses can be induced by different quenching procedures and that bainitic hardening can result in advantages especially for bearing applications.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88414054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fachtagung Entgrattechnologien und Präzisionsoberflächen","authors":"","doi":"10.1515/htm-2022-0009","DOIUrl":"https://doi.org/10.1515/htm-2022-0009","url":null,"abstract":"","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75346804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Additive manufacturing of tool steels represents a great challenge, yet it offers new possibilities for the tool manufacture of, for example, complex forming tools with conformal cooling. First, this contribution gives an overview of the most relevant additive manufacturing processes, the materials and processing concepts. By means of a hybrid manufactured press hardening tool for high-strength sheet metal parts, an example of practical implementation is presented subsequently.
{"title":"Additive Manufacturing of Tool Steels*","authors":"C. Escher, C. Mutke","doi":"10.1515/htm-2022-1002","DOIUrl":"https://doi.org/10.1515/htm-2022-1002","url":null,"abstract":"Abstract Additive manufacturing of tool steels represents a great challenge, yet it offers new possibilities for the tool manufacture of, for example, complex forming tools with conformal cooling. First, this contribution gives an overview of the most relevant additive manufacturing processes, the materials and processing concepts. By means of a hybrid manufactured press hardening tool for high-strength sheet metal parts, an example of practical implementation is presented subsequently.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86416343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Wegener, A. Liehr, A. Bolender, S. Degener, F. Wittich, A. Kroll, T. Niendorf
Abstract Micromagnetic non-destructive (NDT) methods offer a great potential for the analysis of near-surface properties after machining due to potential time and cost reduction as well as the option to be implemented into the machining process. As a result, the development of soft sensor concepts including micromagnetic NDT methods is in focus of current investigations in order to eventually improve the surface integrity of machined components and, thus, service life and reliability. However, a preceding calibration based on empirical data as well as a reliable validation is often referred to as one of the main challenges of micromagnetic NDT methods. The present study provides insights into the calibration and validation of a micromagnetic 3MA-II system for NDT analysis of the near-surface properties, with a focus on the residual stress depth profiles after hard turning of 51CrV4 specimens. Different calibration functions as well as a combination of different NDT methods are taken into consideration. The results and the potential of the 3MA system as well as open challenges are critically discussed.
{"title":"Calibration and Validation of Micromagnetic Data for Non-Destructive Analysis of Near-Surface Properties after Hard Turning","authors":"T. Wegener, A. Liehr, A. Bolender, S. Degener, F. Wittich, A. Kroll, T. Niendorf","doi":"10.1515/htm-2021-0023","DOIUrl":"https://doi.org/10.1515/htm-2021-0023","url":null,"abstract":"Abstract Micromagnetic non-destructive (NDT) methods offer a great potential for the analysis of near-surface properties after machining due to potential time and cost reduction as well as the option to be implemented into the machining process. As a result, the development of soft sensor concepts including micromagnetic NDT methods is in focus of current investigations in order to eventually improve the surface integrity of machined components and, thus, service life and reliability. However, a preceding calibration based on empirical data as well as a reliable validation is often referred to as one of the main challenges of micromagnetic NDT methods. The present study provides insights into the calibration and validation of a micromagnetic 3MA-II system for NDT analysis of the near-surface properties, with a focus on the residual stress depth profiles after hard turning of 51CrV4 specimens. Different calibration functions as well as a combination of different NDT methods are taken into consideration. The results and the potential of the 3MA system as well as open challenges are critically discussed.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82353791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Surface hardening is an economical and technological alternative to case hardening, especially for larger gear sizes. Due to the high carburization depths required for case hardening with large component dimensions and technological limitations (e. g. furnace size), typical surface hardening processes such as flame or induction hardening show advantages here. In this publication, a flame-spin-hardened variant is compared with an induction-hardened variant using the gap-by-gap method. Both variants have a gear size of mn = 14 mm. A comparison is also made with a case-hardened, shot-peened reference variant of comparable size. In the comparison, the chemical composition, microstructural properties, hardness-depth characteristics and experimental results of the tooth root bending strength tests on the pulsator test rig are presented, comparatively evaluated and discussed. The experimentally determined tooth root load carrying capacities of the two surface-hardened variants are then classified with the reference variant in the state of the art.
{"title":"Flame and Induction Hardening – An Advantageous Alternative to Case Hardening for Large Size Gears?","authors":"H. Cermak, T. Tobie, K. Stahl","doi":"10.1515/htm-2021-2001","DOIUrl":"https://doi.org/10.1515/htm-2021-2001","url":null,"abstract":"Abstract Surface hardening is an economical and technological alternative to case hardening, especially for larger gear sizes. Due to the high carburization depths required for case hardening with large component dimensions and technological limitations (e. g. furnace size), typical surface hardening processes such as flame or induction hardening show advantages here. In this publication, a flame-spin-hardened variant is compared with an induction-hardened variant using the gap-by-gap method. Both variants have a gear size of mn = 14 mm. A comparison is also made with a case-hardened, shot-peened reference variant of comparable size. In the comparison, the chemical composition, microstructural properties, hardness-depth characteristics and experimental results of the tooth root bending strength tests on the pulsator test rig are presented, comparatively evaluated and discussed. The experimentally determined tooth root load carrying capacities of the two surface-hardened variants are then classified with the reference variant in the state of the art.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88915870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Werner, H. Che, M. Lei, T. Christiansen, M. Somers
Abstract Low-temperature carburizing dramatically enhances the inherently low wear resistance of austenitic stainless steels due to the formation of a carbon-supersaturated solid solution, i.e. expanded austenite. The formation of expanded austenite from low-temperature carburizing has been intensively investigated. However, the influence of chemical composition of the stainless steel on the carburizing response has not received the same interest. This contribution addresses the effect of the chemical composition on low-temperature carburizing in terms of carbon solubility, decomposition of expanded austenite upon exceeding the solubility limit and the elasto-plastic accommodation of the carbon-induced lattice expansion. The results demonstrate that the carbon solubility increases with an increasing Cr-equivalent and that higher Cr- and Ni-equivalents favor the formation of Cr-based M7C3 over Fe-based Hägg (M5C2) carbide.
{"title":"Low Temperature Carburizing of Stainless Steels and the Development of Carbon Expanded Austenite*","authors":"K. Werner, H. Che, M. Lei, T. Christiansen, M. Somers","doi":"10.1515/htm-2022-0001","DOIUrl":"https://doi.org/10.1515/htm-2022-0001","url":null,"abstract":"Abstract Low-temperature carburizing dramatically enhances the inherently low wear resistance of austenitic stainless steels due to the formation of a carbon-supersaturated solid solution, i.e. expanded austenite. The formation of expanded austenite from low-temperature carburizing has been intensively investigated. However, the influence of chemical composition of the stainless steel on the carburizing response has not received the same interest. This contribution addresses the effect of the chemical composition on low-temperature carburizing in terms of carbon solubility, decomposition of expanded austenite upon exceeding the solubility limit and the elasto-plastic accommodation of the carbon-induced lattice expansion. The results demonstrate that the carbon solubility increases with an increasing Cr-equivalent and that higher Cr- and Ni-equivalents favor the formation of Cr-based M7C3 over Fe-based Hägg (M5C2) carbide.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74578788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kurzfassung Härte und Korngröße von Zahnrädern aus hochreinen Zahnradstählen nach Einsatzhärtung und Kugelstrahlen wurden im Rahmen eines Forschungsprojekts untersucht, dessen Schwerpunkt auf der Bestimmung der Zahnfußtragfähigkeit von einsatzgehärteten, kugelgestrahlten Zahnrädern lag. Die häufigste Versagensart bei diesen hochfesten Zahnrädern ist der Zahnfußbruch, der durch eine Rissinitiierung unterhalb der Oberfläche an einem nicht-metallischen Einschluss verursacht wird (Bruchlinsenversagen, im Englischen: Fisheye failure). Neben solchen Einschlüssen sind auch die Härte und die Abschreckkorngröße dafür bekannt, dass sie einen erheblichen Einfluss auf die Tragfähigkeit eines Zahnrades haben. Um sicherzustellen, dass in diesem Forschungsprojekt ausschließlich der Einfluss von nicht-metallischen Einschlüssen untersucht wird, mussten mögliche Quereinflüsse ausgeschlossen, minimiert oder zumindest bekannt sein. Nach einem ungeeigneten Einsatzhärtungsprozess erreichen Zahnräder jedoch nicht die härtebezogenen Spezifikationen, oder Zahnräder aus Zahnradstählen mit hoher Feinkornstabilität können Mengen an gröberen Körnern enthalten. Daher wurden Einsatzhärtungsparameter abgeleitet und überprüft, ob sie zu den für einsatzgehärtete Zahnradstähle geforderten Korngrößen- und Härtespezifikationen nach ISO 6336 führen. Weiterhin wurde untersucht, wie sich ein reduzierter Aluminiumgehalt bei resultierenden höheren Reinheitsgrad, d. h. kompensiert durch eine Nioblegierung zur Erhaltung der Feinkornstabilität, auf die Korngröße nach dem Einsatzhärten auswirkt.
{"title":"Investigations on the Hardness and Grain Size of Gears made out of Ultra-Clean Gear Steels after Case-Hardening","authors":"D. Fuchs, E. Fiederling, T. Tobie, K. Stahl","doi":"10.1515/htm-2021-2025","DOIUrl":"https://doi.org/10.1515/htm-2021-2025","url":null,"abstract":"Kurzfassung Härte und Korngröße von Zahnrädern aus hochreinen Zahnradstählen nach Einsatzhärtung und Kugelstrahlen wurden im Rahmen eines Forschungsprojekts untersucht, dessen Schwerpunkt auf der Bestimmung der Zahnfußtragfähigkeit von einsatzgehärteten, kugelgestrahlten Zahnrädern lag. Die häufigste Versagensart bei diesen hochfesten Zahnrädern ist der Zahnfußbruch, der durch eine Rissinitiierung unterhalb der Oberfläche an einem nicht-metallischen Einschluss verursacht wird (Bruchlinsenversagen, im Englischen: Fisheye failure). Neben solchen Einschlüssen sind auch die Härte und die Abschreckkorngröße dafür bekannt, dass sie einen erheblichen Einfluss auf die Tragfähigkeit eines Zahnrades haben. Um sicherzustellen, dass in diesem Forschungsprojekt ausschließlich der Einfluss von nicht-metallischen Einschlüssen untersucht wird, mussten mögliche Quereinflüsse ausgeschlossen, minimiert oder zumindest bekannt sein. Nach einem ungeeigneten Einsatzhärtungsprozess erreichen Zahnräder jedoch nicht die härtebezogenen Spezifikationen, oder Zahnräder aus Zahnradstählen mit hoher Feinkornstabilität können Mengen an gröberen Körnern enthalten. Daher wurden Einsatzhärtungsparameter abgeleitet und überprüft, ob sie zu den für einsatzgehärtete Zahnradstähle geforderten Korngrößen- und Härtespezifikationen nach ISO 6336 führen. Weiterhin wurde untersucht, wie sich ein reduzierter Aluminiumgehalt bei resultierenden höheren Reinheitsgrad, d. h. kompensiert durch eine Nioblegierung zur Erhaltung der Feinkornstabilität, auf die Korngröße nach dem Einsatzhärten auswirkt.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88744489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Fixture-hardening, also known as quench-press hardening, is a widespread process mainly for the automotive industry. This paper introduces a new inductive hardening and tempering process that combines the well-known advantages of induction heating and hardening with the advantages of a fixture hardening process to obtain highly precise workpieces with enormously reduced or even without rework. The main component is a new hardening machine with implemented fixture hardening assembly and integrated induction coil, all in a protective gas atmosphere. Induction as electrical energy source can be used for heating up workpieces prior to fixture hardening and for tempering, which allows to simultaneously draw out the calibration mandrel without any abrasive wear on its surface. In certain applications, an expanding mandrel can be used in order to relieve the workpiece.
{"title":"Gearbox Production Using Distortion Controlled Inductive Fixture Hardening*","authors":"S. Knauf, K. Buchner, R. Jenne","doi":"10.1515/htm-2022-0003","DOIUrl":"https://doi.org/10.1515/htm-2022-0003","url":null,"abstract":"Abstract Fixture-hardening, also known as quench-press hardening, is a widespread process mainly for the automotive industry. This paper introduces a new inductive hardening and tempering process that combines the well-known advantages of induction heating and hardening with the advantages of a fixture hardening process to obtain highly precise workpieces with enormously reduced or even without rework. The main component is a new hardening machine with implemented fixture hardening assembly and integrated induction coil, all in a protective gas atmosphere. Induction as electrical energy source can be used for heating up workpieces prior to fixture hardening and for tempering, which allows to simultaneously draw out the calibration mandrel without any abrasive wear on its surface. In certain applications, an expanding mandrel can be used in order to relieve the workpiece.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84925531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Low-pressure carburizing (LPC) is a recipe-controlled process for surface layer hardening. These recipes are mainly based on experience and contain the process parameters used to achieve the desired hardening result. The process parameters influence the chemical gradients which have set in the boundary layer, the local microstructure and the depth distribution of the process-induced residual stresses. Within the scope of this work, a systematic parameter study and advanced characterization was carried out to quantify the influence of these process parameters on the resulting material state. The varied parameters include the carburizing temperature, the hardening temperature, the quenching rate as well as the number of repetitions and durations of the carburizing cycles’ steps. The results obtained should help to extend the fundamental process understanding of the LPC process. The analyses showed that the retained austenite content and its depth profile change significantly for certain process parameter variations, reaching contents of up to 45 vol% in the near-surface region. The differences regarding the residual stress states of the case-hardened samples can first and foremost be related to the formation of varying depth distributions of the retained austenite.
{"title":"Interrelation between Microstructure and Residual Stresses for Low-Pressure Carburizing of Steel AISI 5120 under Defined Process Parameter Variation","authors":"M. Zuern, O. B. Tapar, P. Ho, J. Épp, J. Gibmeier","doi":"10.1515/htm-2022-0002","DOIUrl":"https://doi.org/10.1515/htm-2022-0002","url":null,"abstract":"Abstract Low-pressure carburizing (LPC) is a recipe-controlled process for surface layer hardening. These recipes are mainly based on experience and contain the process parameters used to achieve the desired hardening result. The process parameters influence the chemical gradients which have set in the boundary layer, the local microstructure and the depth distribution of the process-induced residual stresses. Within the scope of this work, a systematic parameter study and advanced characterization was carried out to quantify the influence of these process parameters on the resulting material state. The varied parameters include the carburizing temperature, the hardening temperature, the quenching rate as well as the number of repetitions and durations of the carburizing cycles’ steps. The results obtained should help to extend the fundamental process understanding of the LPC process. The analyses showed that the retained austenite content and its depth profile change significantly for certain process parameter variations, reaching contents of up to 45 vol% in the near-surface region. The differences regarding the residual stress states of the case-hardened samples can first and foremost be related to the formation of varying depth distributions of the retained austenite.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81211612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"HTM Praxis","authors":"","doi":"10.1515/htm-2022-0006","DOIUrl":"https://doi.org/10.1515/htm-2022-0006","url":null,"abstract":"","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79971418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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