Advances in Ferrous Metallurgy: On-Demand Oral Presentations
Sponsored by: AIST Metallurgy—Processing, Products and Applications Technology Committee
Program Organizers: Daniel Baker, LIFT; Emmanuel De Moor, Colorado School of Mines; Kishlay Mishra, Nucor Castrip Arkansas LLC; Lijia Zhao, Northeastern University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 8
Location: MS&T On Demand
New Roll Alloys Concepts Using in Finishing Stands of Rebar Rolling: Babak Nazari1; Adel Sheikhhosseini1; Hossein Zakerinia1; 1CSMETAL/Chodan Sazan
Cast iron rolls are defined as nodular irons or Nihard irons. The nodular irons used primarily in bar, rod and structural mills, may have either a pearlitic or acicular matrix and may be either statically or centrifugally cast. Some low alloyed irons are a type of Accicular cast iron rolls because of it has constitutes a much higher production tonnage. This paper describes the principle of the AC+ and ACA-Tech rolls concept and its wide range of usability. The AC+ and ACA-Tech concept provides a solution for rod and bar mills to increase performance and output, even under harsh rolling conditions. The main focus is highly loaded mill stands that require both high wear resistance up to 30-40 % and increasing the resistance against thermal fatigue and crack propagation in dog bone, slitter and Finishing stand with the minimum hardness drop in depth and performance.
Research on the Phosphate Capacity of CaO-FeO-MgO-SiO2-MnO-TiO2-V2O5-P2O5 Slags: Yun Zhou1; Rong Zhu1; Kai Dong1; 1University of Science and Technology Beijing
A thermodynamic model for calculating phosphate capacity of CaO-FeO-MgO-SiO2-MnO-TiO2-V2O5-P2O5 slags has been developed based on the IMCT. In this paper, the effects of slag basicity, (%FeO), (%MgO) (%MnO), (%TiO2) and (%V2O5) on phosphate capacity were studied. The results illustrate that there is a parabola relationship between the calculated lgCP and slag basicity, (%FeO), (%TiO2) and (%V2O5), and the increase of slag basicity and (%FeO) will promote the lgCP, conversely, the increase of (%TiO2) and (%V2O5) will decrease the lgCP. Meanwhile, lgCP has a negative linear relationship with (%MgO) and (%MnO). Moreover, the model can predict not only the total phosphate capacity CP of CaO-FeO-MgO-SiO2-MnO-TiO2-V2O5-P2O5 slags, but also the respective contribution of CP,i of nine dephosphorization products, which the generated 3CaOˇP2O5 accounts for 98.93% of contribution to the total phosphate capacity and 4CaOˇP2O5 for 1.06%, 2CaOˇP2O5 for 0.0016%, respectively, while the other structural units only have a negligible contribution.
Radiative Properties of Al-Si Coated 22MnB5 Steel: Cameron Klassen1; Boxuan Zhao1; Kyle Daun1; 1University of Waterloo
Hot stamping of aluminum-silicon (Al-Si) coated 22MnB5 steel blanks is used to produce light and crashworthy vehicle components. Accurate blank heating models are needed to maximize production rates while ensuring the parts are sufficiently austenitized. The heat absorption of the blanks is governed by their radiative properties, which evolve as the Al-Si coating liquefies and transforms into a rough intermetallic layer. However, the connection between surface morphology and radiative properties is poorly understood. This paper presents in-situ emissivity measurements obtained using a Fourier-transform infrared reflectometer equipped with a heated measurement stage, which are compared to ex-situ reflectometer measurements for samples heated in a muffle furnace and quenched at intermediate times, as well as optical roughness profilometry and scanning electron microscope images. The results elucidate the evolving surface characteristics of the steel and provide valuable insight to hot stamping practitioners.
Studying Processing – Microstructure – Mechanical Property Correlation in a Multi-phase Advanced High Strength Steel: Monowar Hossain1; Sanjeev Sharma2; Yanwen Wang2; Daniel Stephens2; Nilesh Kumar1; 1University of Alabama, Tuscaloosa; 2Nucor Steel Decatur, LLC
New types of advanced high strength steels (AHSS) with advanced properties are being designed and developed through proper choice of chemical compositions and processing innovations. By changing processing parameters, number of phases such as ferrite, cementite, and martensite and their fractions can be controlled, thereby controlling mechanical properties of steels. In this work, to investigate effect of microstructure on mechanical property, a multi-phase steel was subjected to several thermal cycles involving different cooling rates using GleebleŽ that led to the evolution of different combinations of microstructure. The microstructural analysis and mechanical testing were carried out using advanced characterization tools including digital image correlation (DIC), in-situ SEM tensile tester, and electron backscatter diffraction (EBSD) before and after plastic deformation. A detailed analysis of the DIC, in-situ tensile test data, and EBSD is in-progress and will be discussed in this presentation.
Evaluation of Different Austenitization Sub-Models for 22MnB5 Steel Using Bayesian Model Selection Technique: Boxuan Zhao1; Constantin Chiriac2; Kyle Daun1; 1University of Waterloo; 2Ford Motor Company
Ultra-high strength steel (UHSS) alloys such as aluminized 22MnB5 are used to produce automotive parts through hot stamping. A thermal-metallurgical model that predicts the blank heating profile and the austenitization progress inside a roller hearth furnace is needed to improve process efficiency and ensure complete austenitization before forming. This paper evaluates two competing austenitization kinetics models: the Johnson-Mehl-Avrami-Kohnogorov (JMAK) model, and internal state variable (ISV) model as candidate metallurgical sub-models, using dilatometry data and temperature profiles from roller hearth furnace trials. Experimental data is used to calibrate the models. Models are assessed using Bayesian model selection technique, which quantify the trade-off between accuracy and complexity.
Effect of CO2 Injection into Blast Furnace Tuyeres on Smelting Parameters: Juanjuan Jiang1; Rong Zhu1; Shengtao Qiu2; 1University of Science and Technology Beijing; 2Central Iron and Steel Research Institute
CO2 injection into blast furnace tuyeres is a new technology to utilize CO2, aiming at expanding the way of CO2 self-absorption in metallurgical industry. In this paper, a mass and energy balance mathematical model is used to analyze the variation of smelting parameters after CO2 injection. Moreover, an industrial test of injecting CO2 into the blast furnace tuyeres performed in a 1780m3 blast furnace. Theoretical analysis and industrial tests show that this technology is feasible, simultaneously, the hot blast consumption per ton of iron is reduced and the heat value of the gas on the top of the furnace is increased. The endothermic reaction between CO2 and carbon leads to the redistribution of heat in the blast furnace, When the injection rate is more than 1%, marginal gas developed, affecting the smooth operation of the blast furnace.Keywords: blast furnace, CO2, smelting parameters, mathematical model