Design, thermomechanical processing and induction hardening of a new medium-carbon steel microalloyed with niobium
Javaheri, Vahid (2019-10-22)
https://urn.fi/URN:ISBN:9789526223582
Kuvaus
Tiivistelmä
Abstract
This thesis has been made within the European Industrial Doctorate (EID) project called Mathematics and Materials Science for Steel Production and Manufacturing, abbreviated as MIMESIS, which has five partners: EFD Induction in Norway; SSAB, Outokumpu, and the University of Oulu in Finland; and Weierstrass Institute for Applied Analysis and Stochastics (WIAS) in Germany. The main aim of this work was to develop a steel composition and processing route suitable for making a slurry transportation pipeline with the aid of induction hardening, and to characterize the phase transformations and microstructures involved in the various stages of the processing route.
A novel steel chemistry was designed based on metallurgical principles assisted by computational thermodynamics and kinetics. The designed composition is a medium-carbon, low-alloy steel microalloyed with niobium, in wt.% 0.40 C, 0.20 Si, 0.25 Mn, 0.50 Mo, 0.90 Cr, and 0.012 Nb. This was subsequently cast, thermomechanically rolled on a laboratory rolling mill to two bainitic microstructures, and finally subjected to the thermal cycles predicted to be encountered with the internal induction hardening of a typical pipe geometry. The phase transformations and microstructures found at various stages of the simulated production process have been characterized and algorithms developed to enable the optimization of microstructure and hardness through the pipe wall thickness.
Tiivistelmä
Tämä väitöskirja on tehty osana Euroopan teollisuustohtori (European Industrial Doctorate, EID) -ohjelmaa projektissa eli Matematiikka ja materiaalitiede teräksen valmistuksessa ja käytössä (Mathematics and Materials Science for Steel Production and Manufacturing, MIMESIS). Ohjelmassa on viisi partneria: EFD Induction Norjasta; SSAB, Outokumpu ja Oulun yliopisto Suomesta; ja Weierstrass Institute for Applied Analysis and Stochastics (WIAS) Saksasta. Työn päätavoitteina oli kehittää teräksen koostumusta ja prosessointireittiä, jotka soveltuvat lietteen kuljetusputken valmistukseen induktiokarkaisun avulla, sekä karakterisoida prosessin eri vaiheiden aikana tapahtuvat faasimuutokset ja mikrorakenteet.
Uusi teräskoostumus suunniteltiin metallurgisten periaatteiden pohjalta hyödyntämällä laskennallista termodynamiikkaa ja kinetiikkaa. Suunniteltu teräs on niobilla mikroseostettu, matalaseosteinen ja keskihiilinen, eli painoprosentteina 0,40 C, 0,20 Si, 0,25 Mn, 0,50 Mo, 0,90 Cr ja 0,012 Nb. Teräs valettiin, valssattiin ja jäähdytettiin termomekaanisesti laboratoriovalssaimella kahdeksi bainiittiseksi mikrorakenteeksi ja lopulta altistettiin lämpösykleille, joiden ennustettiin olevan tyypillisiä sisäisesti induktiokarkaistulle teräsputkelle. Simuloidun tuotantoprosessin eri vaiheissa havaitut faasimuutokset ja mikrorakenteet on karakterisoitu. Sen lisäksi on kehitetty algoritmit, jotka mahdollistavat mikrorakenteen ja kovuuden optimoinnin putken seinämän paksuuden läpi.
Original papers
Original papers are not included in the electronic version of the dissertation.
Javaheri, V., Porter, D., & Kuokkala, V.-T. (2018). Slurry erosion of steel – Review of tests, mechanisms and materials. Wear, 408–409, 248–273. https://doi.org/10.1016/j.wear.2018.05.010
Javaheri, V., Nyyssönen, T., Grande, B., & Porter, D. (2018). Computational design of a novel medium-carbon, low-alloy steel microalloyed with niobium. Materials Engineering and Performance, 27, 2978–2992. https://doi.org/10.1007/s11665-018-3376-9
Javaheri, V., Khodaie, N., Kaijalainen, A., & Porter, D. (2018). Effect of niobium and phase transformation temperature on the microstructure and texture of a novel 0.40% C thermomechanically processed steel. Materials Characterization, 142, 295–308. https://doi.org/10.1016/j.matchar.2018.05.056
Javaheri, V., Kolli, S., Grande, B., & Porter, D. (2019). Insight into the induction hardening behavior of a new 0.40% C microalloyed steel: Effects of initial microstructure and thermal cycles. Materials Characterization, 149, 165–183. https://doi.org/10.1016/j.matchar.2019.01.029
Javaheri, V., Pohjonen, A., Asperheim, J.I., Ivanov, D., & Porter, D. (2019). Physically based modelling, characterization and design of an induction hardening process for a new slurry pipeline steel. Materials and Design, 182, 108047. https://doi.org/10.1016/j.matdes.2019.108047
Osajulkaisut
Osajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.
Javaheri, V., Porter, D., & Kuokkala, V.-T. (2018). Slurry erosion of steel – Review of tests, mechanisms and materials. Wear, 408–409, 248–273. https://doi.org/10.1016/j.wear.2018.05.010
Javaheri, V., Nyyssönen, T., Grande, B., & Porter, D. (2018). Computational design of a novel medium-carbon, low-alloy steel microalloyed with niobium. Materials Engineering and Performance, 27, 2978–2992. https://doi.org/10.1007/s11665-018-3376-9
Javaheri, V., Khodaie, N., Kaijalainen, A., & Porter, D. (2018). Effect of niobium and phase transformation temperature on the microstructure and texture of a novel 0.40% C thermomechanically processed steel. Materials Characterization, 142, 295–308. https://doi.org/10.1016/j.matchar.2018.05.056
Javaheri, V., Kolli, S., Grande, B., & Porter, D. (2019). Insight into the induction hardening behavior of a new 0.40% C microalloyed steel: Effects of initial microstructure and thermal cycles. Materials Characterization, 149, 165–183. https://doi.org/10.1016/j.matchar.2019.01.029
Javaheri, V., Pohjonen, A., Asperheim, J.I., Ivanov, D., & Porter, D. (2019). Physically based modelling, characterization and design of an induction hardening process for a new slurry pipeline steel. Materials and Design, 182, 108047. https://doi.org/10.1016/j.matdes.2019.108047
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