Thermodynamic, Kinetic, and Microstructure Data for Modeling Solidification of Fe-Al-Mn-Si-C Alloys

Miettinen, Jyrki; Koskenniska, Sami; Visuri, Ville‐Valtteri; Somani, Mahesh C.; Fabritius, Timo; Kömi, Jukka

doi:10.1007/s11663-020-01973-y

Cited by 22 publications

(26 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For calculations with the aid of IDS, the steel samples were first cooled at 0.5°C/s from 1600°C to 700°C, because any steel must have its as-cast history. The earlier measurements of the secondary dendrite arm spacing for the steels [54] suggest that 0.5°C/s is a realistic estimation for the cooling rate of their solidification. After reaching 700°C, the samples were heated at 10°C/s to 1100°C and then held for 2 minute at that temperature, following the experimental procedure.…”

Section: Experimental Measurements and Validation Of Calculationsmentioning

confidence: 93%

Optimization of the CCT Curves for Steels Containing Al, Cu and B

Miettinen

Koskenniska

Somani

et al. 2021

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

New continuous cooling transformation (CCT) equations have been optimized to calculate the start temperatures and critical cooling rates of phase formations during austenite decomposition in low-alloyed steels. Experimental CCT data from the literature were used for applying the recently developed method of calculating the grain boundary soluble compositions of the steels for optimization. These compositions, which are influenced by solute microsegregation and precipitation depending on the heating/cooling/holding process, are expected to control the start of the austenite decomposition, if initiated at the grain boundaries. The current optimization was carried out rigorously for an extended set of steels than used previously, besides including three new solute elements, Al, Cu and B, in the CCT-equations. The validity of the equations was, therefore, boosted not only due to the inclusion of new elements, but also due to the addition of more low-alloyed steels in the optimization. The final optimization was made with a mini-tab tool, which discarded statistically insignificant parameters from the equations and made them prudently safer to use. Using a thermodynamic-kinetic software, IDS, the new equations were further validated using new experimental CCT data measured in this study. The agreement is good both for the phase transformation start temperatures as well as the final phase fractions. In addition, IDS simulations were carried out to construct the CCT diagrams and the final phase fraction diagrams for 17 steels and two cast irons, in order to outline the influence of solute elements on the calculations and their relationship with literature recommendations.

show abstract

Section: Experimental Measurements and Validation Of Calculationsmentioning

confidence: 93%

Optimization of the CCT Curves for Steels Containing Al, Cu and B

Miettinen

Koskenniska

Somani

et al. 2021

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

show abstract

“…The package has since been validated with extensive data of solidification experiments [19,21,24]. Recently, the IDS database has been extended to enable improved simulations new steel grades [25,26].…”

Section: Ids and Castmanager/tempsimu Toolsmentioning

confidence: 99%

New phenomenological quality criteria for continuous casting of steel based on solidification and microstructure tool IDS

Louhenkilpi

Miettinen

Visuri

et al. 2020

Ironmaking & Steelmaking

Self Cite

View full text Add to dashboard Cite

Although the formation of defects in continuous casting has been studied for several decades, a deeper understanding and improved quality prediction concepts are needed to correlate the defects with the actual steel compositions, machine data and casting parameters. The aim of this work was to derive new quality criteria based on steel composition and cooling pattern for continuous casting and for the subsequent cooling and reheating processes. The criteria were devised based on the outputs of multiphysics simulation tools for online casting applications. The developed criteria were found to be good predictors of whether a steel grade combined with a given cooling pattern is prone to a specific defect. The criteria useful in providing a theoretical justification as to why certain defects form or would form, and can be used for devising practical solutions to avoid them. In practice, the final determination of whether a defect will form depends on the cumulative impact of various single quality criteria combined with the models/data describing the mechanical and thermal stresses forming. The criteria proposed are applicable as part of online quality prediction systems in casting machines. In this paper, new quality criteria were proposed for different kind of cracking-related and gas defects along with case examples. In further work, the criteria will be used to develop rule-based online control systems, in which cumulative effects of individual quality criteria are combined with data from mechanical and thermal stress calculations.

show abstract

“…In this case, computer simulations of the welding process and thermodynamic simulations can be used to predict the HAZ thermal cycles and microstructures under different welding conditions (e.g., IT); this speed up the analysis and makes it less expensive. Computer simulations of welding ( nite element method, FEM) [14][15][16][17][18] and thermodynamics (Calphad method) [12,[19][20] have developed in recent years.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Dornelas

Filho

Oliveira

et al. 2021

Preprint

View full text Add to dashboard Cite

Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness stees, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness, but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

show abstract

Thermodynamic, Kinetic, and Microstructure Data for Modeling Solidification of Fe-Al-Mn-Si-C Alloys

Cited by 22 publications

References 60 publications

Optimization of the CCT Curves for Steels Containing Al, Cu and B

Optimization of the CCT Curves for Steels Containing Al, Cu and B

New phenomenological quality criteria for continuous casting of steel based on solidification and microstructure tool IDS

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Contact Info

Product

Resources

About