Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel

Dilatometry was used to simulate and analyze martensite formation in the grain-coarsened heat-affected zone (GCHAZ) of P91 steel for high inter-pass temperatures during multi-pass welding. The inter-pass temperature of 360 °C was within the dual-phase temperature range (~400 °C to 240 °C), but becau...

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Main Authors: Druce Dunne, Huijun Li, Elena Pereloma
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/15/5/501
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author Druce Dunne
Huijun Li
Elena Pereloma
author_facet Druce Dunne
Huijun Li
Elena Pereloma
author_sort Druce Dunne
collection DOAJ
description Dilatometry was used to simulate and analyze martensite formation in the grain-coarsened heat-affected zone (GCHAZ) of P91 steel for high inter-pass temperatures during multi-pass welding. The inter-pass temperature of 360 °C was within the dual-phase temperature range (~400 °C to 240 °C), but because of the unexpected formation of isothermal martensite, the microstructure at the inter-pass temperature was substantially martensitic and similar in microstructure and hardness to those obtained using lower, conventional inter-pass temperatures (about 250 °C). The results for martensite formation indicate that kinetic classifications for transformation in carbon and alloyed steels should take into account the overlapping effects of the diffusionless transformation and thermally activated processes associated with dislocation motion and the diffusion of interstitial elements. Furthermore, the M<sub>S</sub> temperature was found to be highly sensitive to the microstructural state of the austenite and the availability of nucleating sites for martensite formation. The data for the kinetics of martensite formation were inconsistent with the widely used Koistinen and Marburger (KM) equation for predicting the volume fraction of martensite as a function of quench temperature. It is concluded that the KM equation has limited applicability
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spelling doaj-art-3e5a3a1ec10a4ddcaa67951935f18a972025-08-20T02:34:01ZengMDPI AGMetals2075-47012025-04-0115550110.3390/met15050501Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 SteelDruce Dunne0Huijun Li1Elena Pereloma2School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaSchool of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaSchool of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaDilatometry was used to simulate and analyze martensite formation in the grain-coarsened heat-affected zone (GCHAZ) of P91 steel for high inter-pass temperatures during multi-pass welding. The inter-pass temperature of 360 °C was within the dual-phase temperature range (~400 °C to 240 °C), but because of the unexpected formation of isothermal martensite, the microstructure at the inter-pass temperature was substantially martensitic and similar in microstructure and hardness to those obtained using lower, conventional inter-pass temperatures (about 250 °C). The results for martensite formation indicate that kinetic classifications for transformation in carbon and alloyed steels should take into account the overlapping effects of the diffusionless transformation and thermally activated processes associated with dislocation motion and the diffusion of interstitial elements. Furthermore, the M<sub>S</sub> temperature was found to be highly sensitive to the microstructural state of the austenite and the availability of nucleating sites for martensite formation. The data for the kinetics of martensite formation were inconsistent with the widely used Koistinen and Marburger (KM) equation for predicting the volume fraction of martensite as a function of quench temperature. It is concluded that the KM equation has limited applicabilityhttps://www.mdpi.com/2075-4701/15/5/501alloy steelmulti-pass weldingP91heat affected zonemartensitic transformationdilatometry
spellingShingle Druce Dunne
Huijun Li
Elena Pereloma
Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
Metals
alloy steel
multi-pass welding
P91
heat affected zone
martensitic transformation
dilatometry
title Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
title_full Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
title_fullStr Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
title_full_unstemmed Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
title_short Effect of Inter-Pass Temperature and Time on Martensite Formation in the Heat-Affected Zone During Multi-Pass Welding of P91 Steel
title_sort effect of inter pass temperature and time on martensite formation in the heat affected zone during multi pass welding of p91 steel
topic alloy steel
multi-pass welding
P91
heat affected zone
martensitic transformation
dilatometry
url https://www.mdpi.com/2075-4701/15/5/501
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