Physically based modeling, characterization and design of an induction hardening process for a new slurry pipeline steel

Javaheri, Vahid; Pohjonen, Aarne; Asperheim, John Inge; Ivanov, Dmitry; Porter, David

doi:10.1016/j.matdes.2019.108047

Cited by 42 publications

(24 citation statements)

References 20 publications

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“…The ridge-like regions consist of clusters of fine martensite laths, which etch to different degrees thereby creating the ridge appearance. It has been shown ferrite with a higher concentration of carbon in solid solution etches less in nital as does carbon supersaturated retained austenite at the lath boundaries [21]. Within the ridge-like regions, carbides were either absent or smaller in size than the carbides found in the coarse auto-tempered regions.…”

mentioning

confidence: 99%

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Babu

Nyyssönen

Jaskari

et al. 2019

Metals

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Auto-tempering is a feature of the technologically important as-quenched low-carbon martensitic steels. The focus of this paper is on the morphology of the martensite and the orientation of the last forming untempered regions in relation to the earlier formed auto-tempered martensite in both small and large austenite grains. A low-carbon martensitic steel plate was austenitized for 24 h and quenched to room temperature. The resulting microstructure was characterized using electron microscopy and electron back scattered diffraction (EBSD) imaging. It was found that all the untempered regions in the martensitic microstructure were oriented with the plane normals {100} close to the thickness, or normal, direction of the plates. Variant analysis revealed that the untempered regions and the auto-tempered regions are part of the same packet.

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mentioning

confidence: 99%

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Babu

Nyyssönen

Jaskari

et al. 2019

Metals

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“…The optimization is performed for two separate industrial processes: induction hardening of a medium carbon, low-alloy pipe steel (Javaheri et al, 2019b) and a water cooling of a hot rolled low carbon steel strip (Pohjonen et al, 2018a). The optimization workflow consists of first setting the desired amounts of microstructural constituents, and subsequent optimization of the thermal path, which produces these desired amounts applying the phase transformation model described in (Pohjonen et al, 2018a;Pohjonen et al, 2018b;Javaheri et al, 2019b). For the water cooling of a steel strip, we additionally employed previously developed tool (Paananen, 2015;Pohjonen et al, 2016) to calculate the cooling water fluxes that are needed to realize the optimized cooling path in water cooling line after hot rolling.…”

Section: Aimsmentioning

confidence: 99%

“…The phase transformation module has been described in detail generally in (Pohjonen et al, 2018b), in context of induction hardening of medium carbon steel (Javaheri et al, 2019b) and in the context of water cooling of hot rolled low carbon steel in (Pohjonen et al, 2018a), where (Javaheri et al, 2019b) and (Pohjonen et al, 2018a) also include the transformation model parameters fitted for the steels that were used in these examples.…”

Section: Sims 61mentioning

confidence: 99%

Semi-Automatic Optimization of Steel Heat Treatments for Achieving Desired Microstructure

Pohjonen¹,

Javaheri²,

Paananen³

et al. 2021

Linköping Electronic Conference Proceedings

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The thermo-mechanical processing history together with the steel composition defines the final microstructure, which in turn produces the macroscopic mechanical properties of the final product. In many industrial processes it is therefore of paramount importance to find the optimal thermal path that produces the desired microstructure. In the current study an optimization method has been developed to calculate the optimal thermal path for producing desired amounts of microstructural constituents (ferrite, bainite, martensite) of a medium carbon, low-alloy steel, and a low carbon microalloyed steel. The optimization is performed for two separate industrial processes: induction hardening of a pipeline steel and a water cooling of hot rolled steel strip. The optimization workflow consists of first setting the desired amounts of microstructural constituents, and subsequent optimization of the thermal path, which produces these desired amounts. For the water cooling of a steel strip we additionally employed previously developed tool to calculate the cooling water fluxes that are needed to realize the optimized cooling path in water cooling line after hot rolling. To demonstrate the applicability of the method, we present results that were obtained for different case studies related to the industrial processes.

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“…To accurately characterize and quantify the complex CGHAZ microstructures, EBSD image quality (IQ) analysis was used. As different morphologies vary in intrinsic dislocation density and give different IQ values [30], the normalized IQ data were analyzed on the basis of previous work by DeArdo [31]. In this method, the normalized IQ histogram was deconvoluted into multiple peaks with a normal distribution and then the ratio of area under each peak to the area of IQ curve was considered as a fraction associated with each morphology or phase.…”

Section: Iq Analysismentioning

confidence: 99%

Characterization of Coarse-Grained Heat-Affected Zones in Al and Ti-Deoxidized Offshore Steels

Tervo

Kaijalainen

Javaheri

et al. 2020

Metals

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Deterioration of the toughness in heat-affected zones (HAZs) due to the thermal cycles caused by welding is a known problem in offshore steels. Acicular ferrite (AF) in the HAZ is generally considered beneficial regarding the toughness. Three experimental steels were studied in order to find optimal conditions for the AF formation in the coarse-grained heat-affected zone (CGHAZ). One of the steels was Al-deoxidized, while the other two were Ti-deoxidized. The main focus was to distinguish whether the deoxidation practice affected the AF formation in the simulated CGHAZ. First, two different peak temperatures and prolonged annealing were used to study the prior austenite grain coarsening. Then, the effect of welding heat input was studied by applying three cooling times from 800 °C to 500 °C in a Gleeble thermomechanical simulator. The materials were characterized using electron microscopy, energy-dispersive X-ray spectrometry, and electron backscatter diffraction. The Mn depletion along the matrix-particle interface was modelled and measured. It was found that AF formed in the simulated CGHAZ of one of the Ti-deoxidized steels and its fraction increased with increasing cooling time. In this steel, the inclusions consisted mainly of small (1–4 μm) TiOx-MnS, and the tendency for prior austenite grain coarsening was the highest.

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Physically based modeling, characterization and design of an induction hardening process for a new slurry pipeline steel

Cited by 42 publications

References 20 publications

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Semi-Automatic Optimization of Steel Heat Treatments for Achieving Desired Microstructure

Characterization of Coarse-Grained Heat-Affected Zones in Al and Ti-Deoxidized Offshore Steels

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