HTM Journal of Heat Treatment and Materials

Published by De Gruyter

Volume 76 Issue 6

December 2021

Issue of HTM Journal of Heat Treatment and Materials

Contents
Journal Overview

Publicly Available December 31, 2021

Page range: 385-386

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December 31, 2021

Preface to the special issue/Vorwort zum Sonderheft

Page range: 388-389

Publicly Available December 31, 2021

Quenching and Distortion*

R. Fechte-Heinen, Th. Lübben

Page range: 390-416

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Abstract

This paper is based on a keynote lecture presented by Prof. Fechte-Heinen during the 2 nd 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.

December 31, 2021

In situ Investigation during Low Pressure Carburizing by Means of Synchrotron X-ray Diffraction*

O. B. Tapar, M. Steinbacher, J. Gibmeier, N. Schell, J. Epp

Page range: 417-431

Abstract

In situ X-ray diffraction investigations during low pressure carburizing (LPC) processes were performed with a specially developed process chamber at the German Electron Synchrotron Facility (DESY) in Hamburg, Germany. Carbon saturation in austenite was reached in less than 20 seconds for all processes with different parameters and carbides formed at the surface. Therefore, the direct contribution of carbon donor gas to the carbon profile after 20 seconds was reduced to very low levels. After that point, further supply of carbon donor gas increased the amount of carbides formed at the surface, which will contribute to the carbon profile indirectly by dissolution in the following diffusion steps. During quenching, martensite at higher temperatures had a lower c/a ratio than later formed ones. This difference is credited to self-tempering effects and reordering of carbon atoms within the martensite lattice.

December 31, 2021

Advanced Distortion Analysis of Heat Treated Rings*

H. Surm

Page range: 432-444

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.

December 31, 2021

Comparison of the Hardness-Toughness Relationship of Medium-Mn Steels after Q&T and Q&P Treatments*

R. Schneider, S. Kaar, S. Schneider, D. Krizan, C. Sommitsch

Page range: 445-457

Abstract

In contrast to quenching and tempering (Q&T), with quenching to room temperature, quenching and partitioning (Q&P) usually applies quenching to a temperature between M s and room temperature. To stabilize a sufficient amount of retained austenite (RA), carbon diffusion from martensite into austenite and a prevention of cementite formation takes place during the successive partitioning step. Larger amount of RA, and its transformation into martensite during plastic deformation, provides Q&P treated steels with an enhanced combination of strength and ductility. In this investigation, the effect of different Q&T and Q&P treatments on the hardness-toughness relationship was determined. These results are compared with the RA contents and mechanical properties provided by tensile testing. The obtained results clearly demonstrate that the optimum parameters for strength and ductility do not match with the best combinations of hardness and toughness. Furthermore, the stability of the RA plays an important role in the understanding of toughness properties of the investigated Q&P steels.

December 31, 2021

Transformation Plasticity in Carbonitrided PM-Steels: Quantification of Plasticity Effects in Dependence of the Part Density*

J. M. Damon, S. Dietrich, V. Schulze

Page range: 458-477

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.

Publicly Available December 31, 2021

Impressum/Imprint

Page range: 478-478

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From and for Practice / Praxis-Informationen

Publicly Available December 31, 2021

AWT-Info / HTM 06-2021

Page range: A5-A19

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Publicly Available December 31, 2021

HTM Praxis

Page range: A20-A36

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About this journal

HTM is a bilingual (German-English) independently assessed and periodical standard publication that provides reports on all aspects of heat treatment and material technology in research and production. By publishing trend-setting contributions to research and practical experience reports, HTM helps in answering scientific questions as well as regarding investment decisions in the industry. All articles are subject to thorough, independent peer review.
HTM is the official organ of AWT – the Association of Heat Treatment and Materials Technology.

Volume 76 Issue 6

Issue of HTM Journal of Heat Treatment and Materials

Contents

Obituary/Nachruf

Preface to the special issue/Vorwort zum Sonderheft

Quenching and Distortion*

Abstract

In situ Investigation during Low Pressure Carburizing by Means of Synchrotron X-ray Diffraction*

Abstract

Advanced Distortion Analysis of Heat Treated Rings*

Abstract

Comparison of the Hardness-Toughness Relationship of Medium-Mn Steels after Q&T and Q&P Treatments*

Abstract

Transformation Plasticity in Carbonitrided PM-Steels: Quantification of Plasticity Effects in Dependence of the Part Density*

Abstract

Impressum/Imprint

AWT-Info / HTM 06-2021

HTM Praxis