- document
-
Celada-Casero, Carola (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)There is sufficient experimental evidence to propose that the formation kinetics of athermal martensite directly depends on the austenite grain structure from which the martensite forms. Yet, this dependence is frequently ignored. The present study investigates the role of the prior austenite grain size (PAGS) in the martensitic...journal article 2019
- document
-
Vittorietti, M. (author), Kok, Piet J.J. (author), Sietsma, J. (author), Jongbloed, G. (author)Understanding the intricate and complex materials microstructure and how it is related to materials properties is an important problem in the Materials Science field. For a full comprehension of this relation, it is fundamental to be able to describe the main characteristics of the 3-dimensional microstructure. The most basic model used for...journal article 2019
- document
-
Kumar, A. (author), Agarwal, G. (author), Petrov, R.H. (author), Goto, S. (author), Sietsma, J. (author), Herbig, M. (author)The formation of White (WEL) and Brown Etching Layers (BEL) on rail raceways during service causes the initiation of microcracks which finally leads to failure. Detailed characterization of the WEL and the BEL in a pearlitic rail steel is carried out from micrometer to atomic scale to understand their microstructural evolution. A...journal article 2019
- document
-
Chen, Z. (author), Qu, Ying xia (author), Zeilstra, Christiaan (author), Van Der Stel, Jan (author), Sietsma, J. (author), Yang, Y. (author)HIsarna is a promising ironmaking technology to reduce CO <sub>2</sub> emission. Information of phase transformation is essential for reaction analysis of the cyclone reactor of the HIsarna process. In addition, data of density and volume of the ore particles are necessary for estimation of the residence time of the particles in the cyclone...journal article 2019
- document
-
Goulas, C. (author), Kumar, A. (author), Mecozzi, M.G. (author), Castro-Cerda, Felipe Manuel (author), Herbig, Michael (author), Petrov, R.H. (author), Sietsma, J. (author)Atomic-scale investigation was performed on 51CrV4 steel, isothermally held at different temperatures within the bainitic temperature range. Transmission electron microscopy (TEM) analysis revealed three different morphologies: lower, upper, and inverse bainite. Atom Probe Tomography (APT) analysis of lower bainite revealed cementite...journal article 2019
- document
-
Karewar, S.V. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Molecular dynamics simulations are used to investigate the atomic effects of carbon (C) addition in Fe on the martensitic phase transformation in the presence of pre-existing defects such as stacking faults and twin boundaries. The pre-existing defect structures in Fe-C alloys have the same effect on the atomistic mechanisms of martensitic...journal article 2019
- document
-
Celada-Casero, Carola (author), Kwakernaak, C. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)The influence of the prior austenite grain size (PAGS), varying between 6 and 185 μm, on the microstructural development of a low carbon steel during quenching and partitioning (Q&P) processing is investigated. The effect on the size and morphological aspects of the microconstituents is discussed based on the kinetics of carbon...journal article 2019
- document
-
Gavel, D.J. (author), Adema, A.T. (author), Stel, Jan Van Der (author), Sietsma, J. (author), Boom, R. (author), Yang, Y. (author)One of the primary causes that limit the blast furnace productivity is the resistance exerted to the gas flow in the cohesive zone by the ferrous burden. Use of nut coke (10–40 mm) together with ferrous burden proves beneficial for decreasing this resistance. In present study, effect of nut coke addition on the olivine fluxed iron ore pellet...journal article 2019
- document
-
Kumar, A. (author), Saxena, A. K. (author), Kirchlechner, C. (author), Herbig, M. (author), Brinkmann, S. (author), Petrov, R.H. (author), Sietsma, J. (author)Failure in engineering materials like steels is strongly affected by in-service deleterious alterations in their microstructure. White Etching Layers (WELs) are an example of such in-service alterations in the pearlitic microstructure at the rail surface. Cracks initiate in the rails due to delamination and fracture of these layers and...journal article 2019
- document
-
Ioannidou, C. (author), Arechabaleta Guenechea, Z. (author), Navarro Lopez, A. (author), Rijkenberg, Arjan (author), Dalgliesh, Robert M. (author), Kölling, S. (author), Bliznuk, Vitaliy (author), Pappas, C. (author), Sietsma, J. (author), van Well, A.A. (author), Offerman, S.E. (author)The precipitation kinetics of vanadium carbides and its interaction with the austenite-to-ferrite phase transformation is studied in two micro-alloyed steels that differ in vanadium and carbon concentrations by a factor of two, but have the same vanadium-to-carbon atomic ratio of 1:1. Dilatometry is used for heat-treating the specimens and...journal article 2019
- document
-
Ayenampudi, S. (author), Celada-Casero, Carola (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Medium-Mn Quenching & Partitioning (Q&P) steels have been recently considered as potential candidates for the 3rd generation advanced high-strength steels. The processing of these steels aims to induce the partitioning of substitutional alloying elements from martensite to austenite during an isothermal treatment at high temperature,...journal article 2019
- document
-
Hajizad, O. (author), Kumar, A. (author), Li, Z. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural...journal article 2019
- document
-
Kim Lee, B.N. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)Carbon redistribution is known to occur during room temperature aging of Fe-C martensite. One of the proposed mechanisms in the literature by which carbon redistributes is spinodal decomposition, a thermodynamically driven reaction in which the alloy undergoes separation into carbon-rich and carbon-poor regions, giving rise to modulations in...journal article 2019
- document
-
Gavel, D.J. (author), Adema, A.T. (author), van der Stel, Jan (author), Kwakernaak, C. (author), Sietsma, J. (author), Boom, R. (author), Yang, Y. (author)The melting and dripping behaviour of an iron ore pellet bed mixed with nut coke are investigated through a series of quenching, melting and dripping experiments. In the melting bed of iron ore pellets, nut coke acts as a frame to maintain the passage for the gas flow. The iron carburisation level of the pellet shell is found to control the...journal article 2019
- document
-
Schrama, F.N.H. (author), Beunder, Elisabeth M. (author), Visser, H. (author), Sietsma, J. (author), Boom, R. (author), Yang, Y. (author)Carbon may precipitate during the hot metal desulfurization (HMD) process as a result of carbon oversaturation because of temperature decrease. The precipitated carbon flakes form a layer between hot metal and slag. It is postulated that this carbon layer hampers desulfurization with magnesium by preventing MgS particles from reaching the...journal article 2019
- document
-
Chen, Z. (author), Qu, Yingxia (author), Zeilstra, Christiaan (author), van der Stel, Jan (author), Sietsma, J. (author), Yang, Y. (author)Melting and reduction of fine iron ore particles in the gas environment of a HIsarna smelting cyclone is a critically important topic, but very limited information is currently available except for some experimental data from high temperature drop tube furnace (HTDF). This work discusses the equilibrium state of reacting iron ore in the HTDF...journal article 2018
- document
-
Gavel, D.J. (author), Song, Qingshi (author), Adema, A.T. (author), van der Stel, Jan (author), Sietsma, J. (author), Boom, R. (author), Yang, Y. (author)In the blast furnace, nut coke is utilized in a mixture with the ferrous burden to improve the gas permeability. Although applied in a broad range (10–40 mm, 2–23 wt-%), limited information is available on changed burden behaviour in its presence. In the present study, the detailed characterization was performed on the iron ore pellets quenched...journal article 2018
- document
-
Navarro Lopez, A. (author), Hidalgo Garcia, J. (author), Sietsma, J. (author), Santofimia, Maria Jesus (author)The accelerated formation of bainite in presence of martensite is opening a new processing window for the steel industry. However, for a feasible industrial implementation, it is necessary to determine the mechanical behaviour of the steels developed under such conditions. This study focuses on analysing the effects of the formation of...journal article 2018
- document
-
Venkatesan, P. (author), Sun, Z.H.I. (author), Sietsma, J. (author), Yang, Y. (author)In this manuscript, we demonstrate a room temperature electrochemical process for efficiently recycling NdFeB magnet waste. First, the magnet waste was completely leached with HCl and then, in-situ electrochemical oxidation was performed to selectively oxidize Fe(II) in the leachate to Fe(III). Finally, oxalic acid was added directly to the...journal article 2018
- document
-
Naeimi, M. (author), Li, S. (author), Li, Z. (author), Wu, J. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)This research presents a coupled thermomechanical modelling procedure for the wheel-rail contact problem and computes the flash-temperature and stress-strain responses when thermal effects are present. A three-dimensional elasto-plastic finite element model was built considering the wheel-track interaction. When the wheel is running on rail,...journal article 2018