Abstract Stainless steels are commonly used for high precision components, which often are exposed to corrosive media. However, their inferior tribological behaviour restrict the use of these materials in many technical applications. Thermochemical surface hardening is one way to overcome these weaknesses. Solution nitriding in the austenitic range above 1000 °C is mainly used for hardening martensitic and ferritic stainless grades. In austenitic and duplex stainless grades, however, the hardening effect is limited. Additionally, the high process temperatures combined with a necessary rapid cooling may lead to non-desired dimensional changes. Low temperature surface hardening processing below 500 °C here offers interesting alternatives for increasing the wear properties, while maintaining the corrosion resistance. This paper demonstrates the influence of high and low process temperatures of thermochemical surface hardening treatments on the tight dimensional tolerances of a rotationally symmetrical precision component made from cold worked AISI 304. Based on these results, current and new industrial applications, which benefit from low temperature surface hardening, will be discussed.
{"title":"Dimensional Stability of Low Temperature Surface Hardened Stainless Steel Components*","authors":"A. Bauer, K. Schreiner","doi":"10.1515/htm-2021-0022","DOIUrl":"https://doi.org/10.1515/htm-2021-0022","url":null,"abstract":"Abstract Stainless steels are commonly used for high precision components, which often are exposed to corrosive media. However, their inferior tribological behaviour restrict the use of these materials in many technical applications. Thermochemical surface hardening is one way to overcome these weaknesses. Solution nitriding in the austenitic range above 1000 °C is mainly used for hardening martensitic and ferritic stainless grades. In austenitic and duplex stainless grades, however, the hardening effect is limited. Additionally, the high process temperatures combined with a necessary rapid cooling may lead to non-desired dimensional changes. Low temperature surface hardening processing below 500 °C here offers interesting alternatives for increasing the wear properties, while maintaining the corrosion resistance. This paper demonstrates the influence of high and low process temperatures of thermochemical surface hardening treatments on the tight dimensional tolerances of a rotationally symmetrical precision component made from cold worked AISI 304. Based on these results, current and new industrial applications, which benefit from low temperature surface hardening, will be discussed.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75820235","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 This paper is based on a keynote lecture presented by Prof. Fechte-Heinen during the 2nd International Conference on Quenching and Distortion Engineering in April 2021. Firstly, it presents a short summary of the basics of distortion formation. The mechanisms and the potential for distortion with its carriers are discussed in more detail. Furthermore, the method of Distortion Engineering is explained. Finally, selected examples are presented that illustrate the connections between distortion and the quenching process.
{"title":"Quenching and Distortion*","authors":"R. Fechte-Heinen, T. Lübben","doi":"10.1515/htm-2021-0017","DOIUrl":"https://doi.org/10.1515/htm-2021-0017","url":null,"abstract":"Abstract This paper is based on a keynote lecture presented by Prof. Fechte-Heinen during the 2nd International Conference on Quenching and Distortion Engineering in April 2021. Firstly, it presents a short summary of the basics of distortion formation. The mechanisms and the potential for distortion with its carriers are discussed in more detail. Furthermore, the method of Distortion Engineering is explained. Finally, selected examples are presented that illustrate the connections between distortion and the quenching process.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72904019","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 The basic approach to interpret distortion as a system property is accepted in science and industry. The determination of significant factors and interactions on distortion in the overall production process of selected components represents a central point to identify relevant distortion mechanisms. In this context, a component specific distortion description is a major step to answer distortion problems. In the field of ball bearing engineering, roundness deviation of raceways is an important characteristic. But this parameter is not useful for distortion engineering because no information concerning ring shape is given. But in literature, roundness deviation can be separated in its respective forms like oval and triangle shape with harmonic analysis. In addition, this analysis can be used to specify an amplitude and a direction in the different shapes to describe distortion. In this article, harmonic analysis is used for advanced distortion analysis of tapered roller bearing. An analysis in graphical form is introduced, which illustrates both the amount and the direction of distortion.
{"title":"Advanced Distortion Analysis of Heat Treated Rings*","authors":"H. Surm","doi":"10.1515/htm-2021-0019","DOIUrl":"https://doi.org/10.1515/htm-2021-0019","url":null,"abstract":"Abstract The basic approach to interpret distortion as a system property is accepted in science and industry. The determination of significant factors and interactions on distortion in the overall production process of selected components represents a central point to identify relevant distortion mechanisms. In this context, a component specific distortion description is a major step to answer distortion problems. In the field of ball bearing engineering, roundness deviation of raceways is an important characteristic. But this parameter is not useful for distortion engineering because no information concerning ring shape is given. But in literature, roundness deviation can be separated in its respective forms like oval and triangle shape with harmonic analysis. In addition, this analysis can be used to specify an amplitude and a direction in the different shapes to describe distortion. In this article, harmonic analysis is used for advanced distortion analysis of tapered roller bearing. An analysis in graphical form is introduced, which illustrates both the amount and the direction of distortion.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77997742","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}
Lucia Lumbelli (Trieste 1937 – 2019) was one of the most representative figures of the Italian science of education in recent decades. Graduated in Philosophy at the University of Trieste, after her degree she moved to Milan as an assistant at the Education Institute of State University. There she collaborated actively with another great Triestine educationalist, Egle Becchi. While in Milan, she carried out intensive research with the Agostino Gemelli Institute of filmology, producing what today are classic studies on the understanding of the language of film in childhood and on its importance in educational terms. In 1975 she was made Full Professor at the University of Parma. In 1987 she was given the Chair of Experimental Education at the Faculty of Philosophy in the University of Trieste, to eventually move, upon its creation, to the Faculty of Psychology. In retirement from 2010 on, she was nominated Professor Emeritus by the Ministry of Education, University and Research, and continued to attend the Department of Life Sciences until a month before her death, brought about by a terrible disease that had struck her six years earlier. Nevertheless, she continued working up to the last on her two final scientific articles, completing them a week before her death. Lucia Lumbelli’s research focuses upon the child’s language, understanding, and communication. On the theoretical level her references were, on the one hand, the pedagogy of Gestalt – in the version of Wolfgang Metzger (whose fundamental work Psychologie she translated with the publisher Giunti, Florence) – and the “activism” of Georg Kerschensteiner; on the other hand, the so-called “non-directive psychotherapy” of Carl Rogers, seen not so much from a therapeutic point of view as from that of the theorization of non-authoritarian communication. In addition to an impressive body of scientific articles, published in the most important journals, both Italian and international, of the science of education, she has left numerous volumes that constitute a sure point of reference in Italian educational psychology. Among these we remember Comunicazione non autoritaria (1972), La comunicazione filmica (1972), La comprensione come problema (2009).
{"title":"Obituary/Nachruf","authors":"Lothar Spillmann","doi":"10.1515/htm-2021-0015","DOIUrl":"https://doi.org/10.1515/htm-2021-0015","url":null,"abstract":"Lucia Lumbelli (Trieste 1937 – 2019) was one of the most representative figures of the Italian science of education in recent decades. Graduated in Philosophy at the University of Trieste, after her degree she moved to Milan as an assistant at the Education Institute of State University. There she collaborated actively with another great Triestine educationalist, Egle Becchi. While in Milan, she carried out intensive research with the Agostino Gemelli Institute of filmology, producing what today are classic studies on the understanding of the language of film in childhood and on its importance in educational terms. In 1975 she was made Full Professor at the University of Parma. In 1987 she was given the Chair of Experimental Education at the Faculty of Philosophy in the University of Trieste, to eventually move, upon its creation, to the Faculty of Psychology. In retirement from 2010 on, she was nominated Professor Emeritus by the Ministry of Education, University and Research, and continued to attend the Department of Life Sciences until a month before her death, brought about by a terrible disease that had struck her six years earlier. Nevertheless, she continued working up to the last on her two final scientific articles, completing them a week before her death. Lucia Lumbelli’s research focuses upon the child’s language, understanding, and communication. On the theoretical level her references were, on the one hand, the pedagogy of Gestalt – in the version of Wolfgang Metzger (whose fundamental work Psychologie she translated with the publisher Giunti, Florence) – and the “activism” of Georg Kerschensteiner; on the other hand, the so-called “non-directive psychotherapy” of Carl Rogers, seen not so much from a therapeutic point of view as from that of the theorization of non-authoritarian communication. In addition to an impressive body of scientific articles, published in the most important journals, both Italian and international, of the science of education, she has left numerous volumes that constitute a sure point of reference in Italian educational psychology. Among these we remember Comunicazione non autoritaria (1972), La comunicazione filmica (1972), La comprensione come problema (2009).","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89426564","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 To optimize heat treatment processes of case hardened components, heat treatment simulations are used to predict surface layer conditions. Only a precise knowledge and modelling of the transformation processes allows a trustworthy prediction of the hardness and residual stresses in the surface zone. The transformation plasticity mechanism plays an essential role in the heat treatment process and its correct simulation has a significant influence on the resulting calculated residual stress profiles and component distortion. Without considering transformation plasticity, simulative residual stresses are significantly overestimated [1]. In this work, powder metallurgical components are pressed and sintered and subsequently carbonitrided for a dilatometric investigation to characterize the correlation between transformation plasticity effect and the density. The results show a dependence of the austenite-martensite volume change that led to a significant difference of 0.5 Vol-%. A model describing the martensite volume change with respect to density is proposed. This also affects the description of the transformation plasticity constants (K) between K = 5 – 6 × 10–5 MPa–1 in dependence of density. With currently available data, the effect of chemical composition and density cannot be separated and quantified and further studies are therefore necessary to allow such a refinement.
{"title":"Transformation Plasticity in Carbonitrided PM-Steels: Quantification of Plasticity Effects in Dependence of the Part Density*","authors":"J. Damon, S. Dietrich, V. Schulze","doi":"10.1515/htm-2021-0021","DOIUrl":"https://doi.org/10.1515/htm-2021-0021","url":null,"abstract":"Abstract To optimize heat treatment processes of case hardened components, heat treatment simulations are used to predict surface layer conditions. Only a precise knowledge and modelling of the transformation processes allows a trustworthy prediction of the hardness and residual stresses in the surface zone. The transformation plasticity mechanism plays an essential role in the heat treatment process and its correct simulation has a significant influence on the resulting calculated residual stress profiles and component distortion. Without considering transformation plasticity, simulative residual stresses are significantly overestimated [1]. In this work, powder metallurgical components are pressed and sintered and subsequently carbonitrided for a dilatometric investigation to characterize the correlation between transformation plasticity effect and the density. The results show a dependence of the austenite-martensite volume change that led to a significant difference of 0.5 Vol-%. A model describing the martensite volume change with respect to density is proposed. This also affects the description of the transformation plasticity constants (K) between K = 5 – 6 × 10–5 MPa–1 in dependence of density. With currently available data, the effect of chemical composition and density cannot be separated and quantified and further studies are therefore necessary to allow such a refinement.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81715038","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 In vehicle construction, components with high tensile strengths are used, especially in the chassis area. At the same time, these components must have high toughness and be insensitive to cracking. For this purpose, hardened and tempered but also salt-bainitized components are used. The associated usual process chain after steel production consists of forming processes with subsequent cooling of the forging blanks and subsequent heat treatment with renewed heating to set the required material properties. From an energy point of view, heat treatment from the forging heat is desirable, which in addition to shortening the process chain is also associated with a reduction in CO2 emissions. A prototype system for controlled bainitization has been developed, which implements the heat treatment immediately after hot forming by utilizing the still existing forming temperature. Here, a controlled spray field generates both a quenching and an isothermal holding phase. Various sensors generate input variables to cool the workpieces in a controlled manner. This paper gives an overview of the system technology, realized cooling curves and the resulting hardness.
{"title":"Development of a Prototype Plant for the Heat Treatment of Workpieces with Preferably Bainitic Properties","authors":"S. Wagner, T. Streng","doi":"10.1515/htm-2021-0012","DOIUrl":"https://doi.org/10.1515/htm-2021-0012","url":null,"abstract":"Abstract In vehicle construction, components with high tensile strengths are used, especially in the chassis area. At the same time, these components must have high toughness and be insensitive to cracking. For this purpose, hardened and tempered but also salt-bainitized components are used. The associated usual process chain after steel production consists of forming processes with subsequent cooling of the forging blanks and subsequent heat treatment with renewed heating to set the required material properties. From an energy point of view, heat treatment from the forging heat is desirable, which in addition to shortening the process chain is also associated with a reduction in CO2 emissions. A prototype system for controlled bainitization has been developed, which implements the heat treatment immediately after hot forming by utilizing the still existing forming temperature. Here, a controlled spray field generates both a quenching and an isothermal holding phase. Various sensors generate input variables to cool the workpieces in a controlled manner. This paper gives an overview of the system technology, realized cooling curves and the resulting hardness.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79681071","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}
C. Krause, D. Fehrenbach, L. Wolf, M. Kiesewetter, C. Radek, M. Schaudig
Abstract The measurement of Barkhausen noise is one of the non-destructive testing methods which allows the use within the production line and within the cycle time at a high production volume. The aim of the present study was to answer the question, whether it is possible to extract the informations that the Barkhausen noise includes, concerning work-piece conditions, from the signal characteristic and more important assigning these findings. Therefore, soft machined and heat treated shaft components made of the ferromagnetic material Cf53 (1.1213) were analyzed to find characteristics in the Signal that allow to separate clearly an increase in temperature of the tested area from a change in the microstructure. For this purpose the shafts were analyzed at higher temperatures (up to 80 °C) and after an additional annealing process (to change the microstructure specifically). Both investigated situations (higher temperature and modified microstructure) showed different characteristic in the Barkhausen signal, thus an assigning is possible. Metallographic investigation and hardness measurements has been carried out to support the results.
{"title":"Measurement Potential of the Barkhausen Effect for Obtaining Additional Information on the Component Condition in Manufacturing","authors":"C. Krause, D. Fehrenbach, L. Wolf, M. Kiesewetter, C. Radek, M. Schaudig","doi":"10.1515/htm-2021-0014","DOIUrl":"https://doi.org/10.1515/htm-2021-0014","url":null,"abstract":"Abstract The measurement of Barkhausen noise is one of the non-destructive testing methods which allows the use within the production line and within the cycle time at a high production volume. The aim of the present study was to answer the question, whether it is possible to extract the informations that the Barkhausen noise includes, concerning work-piece conditions, from the signal characteristic and more important assigning these findings. Therefore, soft machined and heat treated shaft components made of the ferromagnetic material Cf53 (1.1213) were analyzed to find characteristics in the Signal that allow to separate clearly an increase in temperature of the tested area from a change in the microstructure. For this purpose the shafts were analyzed at higher temperatures (up to 80 °C) and after an additional annealing process (to change the microstructure specifically). Both investigated situations (higher temperature and modified microstructure) showed different characteristic in the Barkhausen signal, thus an assigning is possible. Metallographic investigation and hardness measurements has been carried out to support the results.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74419228","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 In the framework of a research project, the tooth root bending strength of high-strength gears is investigated. The most common type of failure encountered with these shot-peened, case-hardened gears is tooth root breakage caused by a crack initiation below the surface at a non-metallic inclusion (fisheye failure). However, it is well known that case-hardening depth and quenching grain size can have a great influence on a gear’s load carrying capacity. To ensure that this research project solely investigates the influence of non-metallic inclusions, any cross-influences must be excluded or minimized, or at least known. However, in the case of such ultra-clean gear steels, no recommendations or investigations of the influence of case-hardening on material properties are currently available. Therefore, in the framework of this paper, extended investigations are conducted into the effects of different process steps during case-hardening on the resulting material properties of ultra-clean gear steels.
{"title":"Influence of Heating Rate and Soaking Temperature during Case-Hardening on the Hardness and Grain Size of Ultra-Clean Gear Steels","authors":"D. Fuchs, S. Rommel, T. Tobie, K. Stahl, T. Blum","doi":"10.1515/htm-2021-0011","DOIUrl":"https://doi.org/10.1515/htm-2021-0011","url":null,"abstract":"Abstract In the framework of a research project, the tooth root bending strength of high-strength gears is investigated. The most common type of failure encountered with these shot-peened, case-hardened gears is tooth root breakage caused by a crack initiation below the surface at a non-metallic inclusion (fisheye failure). However, it is well known that case-hardening depth and quenching grain size can have a great influence on a gear’s load carrying capacity. To ensure that this research project solely investigates the influence of non-metallic inclusions, any cross-influences must be excluded or minimized, or at least known. However, in the case of such ultra-clean gear steels, no recommendations or investigations of the influence of case-hardening on material properties are currently available. Therefore, in the framework of this paper, extended investigations are conducted into the effects of different process steps during case-hardening on the resulting material properties of ultra-clean gear steels.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81816753","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}
M. Vidoni, S. Sarkar, H. Farivar, J. Sims, M. Jordan, D. Münter
Abstract Fixture hardening is the process of choice when thin-walled, carburized gears need to be heat treated with minimal distortion. Only a few publications have studied and described the phenomena taking place in carburized gears during a fixture hardening process. An integrated approach is proposed to improve the design of hardening fixtures and introduce new strategies and instrumentation to better understand and control the process. The proposed approach is to tightly integrate the knowledge in metallurgy, numerical simulation, process control, and machine design areas to mutually compensate and overcome the current limitations in each single area. An instrumented fixture is designed for a reference gear and tested on an industrial quenching press. The signals from the fixture are combined directly with the signals from the quenching press, recorded, and used to validate and improve the numerical simulation models. Metallurgical simulations are used to predict temperature distribution, phase transformations, distortion, and to identify new process strategies.
{"title":"Simulation of Fixture Hardening for Tool and Process Design Optimization","authors":"M. Vidoni, S. Sarkar, H. Farivar, J. Sims, M. Jordan, D. Münter","doi":"10.1515/htm-2021-0013","DOIUrl":"https://doi.org/10.1515/htm-2021-0013","url":null,"abstract":"Abstract Fixture hardening is the process of choice when thin-walled, carburized gears need to be heat treated with minimal distortion. Only a few publications have studied and described the phenomena taking place in carburized gears during a fixture hardening process. An integrated approach is proposed to improve the design of hardening fixtures and introduce new strategies and instrumentation to better understand and control the process. The proposed approach is to tightly integrate the knowledge in metallurgy, numerical simulation, process control, and machine design areas to mutually compensate and overcome the current limitations in each single area. An instrumented fixture is designed for a reference gear and tested on an industrial quenching press. The signals from the fixture are combined directly with the signals from the quenching press, recorded, and used to validate and improve the numerical simulation models. Metallurgical simulations are used to predict temperature distribution, phase transformations, distortion, and to identify new process strategies.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86447696","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}
J. Damon, S. Pulvermacher, S. Dietrich, V. Schulze
Abstract Case hardening processes such as carbonitriding can be used to improve the performance of powder metallurgical (PM) structural components. The partially open porosity of these components leads to a significant increase in diffusion, which in turn leads to a change in the element gradient in the surface layer (and consequently the surface layer state) compared to melting metallurgic materials. Within the scope of a two-part work, the surface layer states in common densities are investigated after the case hardening process. The present part 2 comprises the characterisation of the resulting surface layer states depending on the carbon and nitrogen profile and the tempering heat treatment. Through the deep rolling and the subsequent carbonitriding treatment, hardness of up to 850 HV0.1, retained austenite contents of up to 25 vol-% and residual stresses of up to –300 MPa are determined across densities. The extensions to the numerical models described in this paper enable the FE model to predict the surface layer states in a wide range of process combinations and densities with an error tolerance of ±20 %.
{"title":"Experimental and Numerical Investigation of the Surface Layer Conditions after Carbonitriding of Powder Metallurgical Steels. Part 2: Surface Layer States in Components of Graded Porosity","authors":"J. Damon, S. Pulvermacher, S. Dietrich, V. Schulze","doi":"10.1515/htm-2021-0009","DOIUrl":"https://doi.org/10.1515/htm-2021-0009","url":null,"abstract":"Abstract Case hardening processes such as carbonitriding can be used to improve the performance of powder metallurgical (PM) structural components. The partially open porosity of these components leads to a significant increase in diffusion, which in turn leads to a change in the element gradient in the surface layer (and consequently the surface layer state) compared to melting metallurgic materials. Within the scope of a two-part work, the surface layer states in common densities are investigated after the case hardening process. The present part 2 comprises the characterisation of the resulting surface layer states depending on the carbon and nitrogen profile and the tempering heat treatment. Through the deep rolling and the subsequent carbonitriding treatment, hardness of up to 850 HV0.1, retained austenite contents of up to 25 vol-% and residual stresses of up to –300 MPa are determined across densities. The extensions to the numerical models described in this paper enable the FE model to predict the surface layer states in a wide range of process combinations and densities with an error tolerance of ±20 %.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73140377","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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