Characterization of Minerals, Metals and Materials 2021: Metallurgical Process Optimization
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Jian Li, CanmetMATERIALS; Mingming Zhang, Baowu Ouyeel Co. Ltd; Bowen Li, Michigan Technological University; Sergio Monteiro, Instituto Militar de Engenharia; Shadia Ikhmayies; Yunus Kalay, Middle East Technical University; Jiann-Yang Hwang, Michigan Technological University; Juan Escobedo-Diaz, University of New South Wales; John Carpenter, Los Alamos National Laboratory; Andrew Brown, Devcom Arl Army Research Office; Rajiv Soman, Eurofins EAG Materials Science LLC; Alex Moser, Naval Research Laboratory
Thursday 2:00 PM
March 18, 2021
Room: RM 15
Location: TMS2021 Virtual
Session Chair: Rajiv Soman, Eurofins EAG Materials Science LLC; Arnab Baksi, Merichem Company
2:00 PM
Structure and Magnetic Properties of Gas-atomized Maraging Steel Powders for Additive Manufacturing: Ganesh Varma Thotakura1; Alex Paul1; Ramasis Goswami2; Tanjore Jayaraman1; 1University of Michigan-Dearborn; 2Naval Research Laboratory
Maraging steels are traditional ultra-high-strength structural alloys prominent in aerospace and hydrospace applications. We evaluated the structure and magnetic properties of gas-atomized maraging steel powder for additive manufacturing, over a range of temperatures, and compared with commercial magnetic alloys. We characterized the structure by a combination of methods: x-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and the magnetic properties by vibrating sample magnetometry. The powders comprised martensite along with traces of retained-austenite and other intermetallics. The powders exhibited the following magnetic behavior at ambient temperature: coercivity (Hc) ~3 kA/m, magnetic anisotropy (K1) ~1.8 x 10^6 J/m3, magnetic remanence (Mr) ~1 Am2/kg, and magnetic saturation (Ms). The Hc, K1, Mr, and Ms increased at sub-ambient temperatures. The magnetic moment per atom (µh) of the powder was estimated to be ~1.93 µB. With the increase in thermal-treatment temperature, the MS and Hc increased and decreased, respectively.
2:20 PM
Effects of Sinter Feed Size on Productivity and Quality of Iron Ore Sinter: Mingming Zhang1; Marcelo Andrade1; 1ArcelorMittal Global R&D
The quality of sinter depends on its raw material chemistry, size distribution and the sintering process parameters. The flame front speed (bed permeability) has been considered as one of the important operating parameters and it mainly depends on the feed size of the sinter. In present work, pot grate sintering tests and plant trials have been carried out with different size distribution of sinter feed to understand the influence of feed size on productivity, and physical properties of the sinter. Sinter productivity increased with increase in feed mean particle size due to increased flame front speed and improved bed permeability with lower sintering time. With optimized moisture and same granulation condition, sinter with feed mean particle size of 3.2 mm (50 wt% over No. 6 mesh) and less fines (less than 10% below No. 60 mesh) yielded better sinter strength with lower return fines (–1/4 inch).
2:40 PM
Characterization of Brazilian Linz Donawitz-LD Steel Sludges: Mery Gomez Marroquin1; Roberto de Avillez2; Sonia Letichevsky2; Dalia Carbonel-Ramos3; Antoni Quintanilla-Balbuena4; Kenny Salazar-Yantas4; 1APMMM/UNI; 2DEQM PUC-Rio; 3FIA UNI; 4FIGMM UNI
Coarse sludge (sample A) and fine sludge (sample B) from a Brazilian Linz Donawitz - LD steelworks integrated plant was characterized. Chemical analysis determined high level content of iron (51.54 - 77.53%) and lower grades of zinc (0.49 - 1.69%). XRD analysis permitted to observe various mineralogical phases, such as: metallic iron, wustite, franklinite, magnetite, portlandite, periclase, calcite, calcium oxide, silicon, moissanite-2H and srebrodolskite. Microscopic Optical and Scanning Electron Microscopic studies shown morphologies of these residues were made up of globular and skeletal aggregates of metallic iron intergrown with crystals of iron oxides especially wustite and a significant presence of calcite and calcium oxide in spherical nodes having particle sizes between 0.12 and 0.15 mm. Scanning Electron Microscopy - Energy Dispersive X-ray spectroscopy studies denoted significant contain of Fe, O and Ca in both samples. In addition, a thermogravimetric analysis by DTG-DSC-TG at 1000° C exhibited a mass loss of 97.43% for the sample A and 92.57% for the sample B.Keywords: Linz Donawitz-LD, LD converter, BOF converter, Steel sludges, Converter process
3:00 PM
Manufacture of Porous Frit Vents using Space Holder Methodology for Radioisotopic Space Power Systems: Gareth Sheppard1; Karl Tassenburg1; Ramy Mesalam1; Bogdan Nenchev1; Joel Strickland1; Hugo Williams1; 1University of Leicester
Porous pure copper frits were produced by sintering via both pressure-less and space holder methods. Frits function both as a gas pressure release path and radioisotopic fine filter for Radioisotopic Thermoelectric Generators (RTG) and Radioisotopic Heater Units (RHU’s). Highly precise and reproducible flow rates are a fundamental requirement in frit vent design, hence accurate characterisation of their morphological structure is crucial. A novel bulk sample characterisation algorithm “GAKTpore” is applied to Scanning-Election-Microscope (SEM) maps to study and quantify the effects of processing parameters on sample heterogeneity, pore dispersion and pore morphology. The purpose of the investigation is to refine the process-property relationships and achieve manufacturable repeatable homogeneous morphological structures. In this study, copper was used as a surrogate for platinum alloys. All frits were tested via a purpose-built/in-house helium precision-flow rig in order to establish a link between permeability and surface morphology. Frits manufactured via the space holder route displayed great potential for the future development of the manufacture of frit vents for European RTG and RHU development programs.