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2. Effect of Ti and S content on the properties and machinability of low-carbon ferritic–pearlitic steelBoštjan Arh, Franc Tehovnik, Franci Vode, Bojan Podgornik, 2024, izvirni znanstveni članek Povzetek: This research was focused on the effect of Ti and S content on the formation of non-metallic inclusions and their influence on the mechanical properties and machinability of low-carbon ferritic– pearlitic steels. An analysis and classification of the non-metallic inclusions were carried out. The tensile strength and impact toughness were determined from samples taken in the rolling direction. Machinability investigations were carried out on a CNC turning machine and by analyzing the surface roughness. TiO-TiN inclusions are present in steels with an increased Ti content. In these steels, the hardness, tensile strength, and cutting forces increase with a higher proportion of Ti. In the second group of steels with increased contents of S, Al, and Ca, MnS and CaO-Al2O3-MnS non-metallic inclusions are formed. As the S content increases, the tensile strength and cutting forces decrease, while the impact toughness increases. In steels with added Ti, the This research was focused on the effect of Ti and S content on the formation of non-metallic inclusions and their influence on the mechanical properties and machinability of low-carbon ferritic– pearlitic steels. An analysis and classification of the non-metallic inclusions were carried out. The tensile strength and impact toughness were determined from samples taken in the rolling direction. Machinability investigations were carried out on a CNC turning machine and by analyzing the surface roughness. TiO-TiN inclusions are present in steels with an increased Ti content. In these steels, the hardness, tensile strength, and cutting forces increase with a higher proportion of Ti. In the second group of steels with increased contents of S, Al, and Ca, MnS and CaO-Al2O3-MnS non-metallic inclusions are formed. As the S content increases, the tensile strength and cutting forces decrease, while the impact toughness increases. In steels with added Ti, the machining is more difficult, but a finer surface is achieved after turning, while a higher S content results in an increased fraction of softer sulfide inclusions, which reduce the cutting forces but also result in a reduced surface quality. turning, while a higher S content results in an increased fraction of softer sulfide inclusions, which reduce the cutting forces but also result in a reduced surface quality.
Ključne besede: non-metallic inclusions, mechanical properties, machinability, surface roughness
Objavljeno v DiRROS: 03.09.2024; Ogledov: 420; Prenosov: 525
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3. Raman microspectroscopy of garnets from Sfibulae from the archaeological site Lajh (Slovenia)Saša Kos, Matej Dolenec, Judita Lux, Sabina Dolenec, 2020, izvirni znanstveni članek Povzetek: Garnets (19 pieces) of Late Antique S-fibulae from the archaeological site at Lajh-Kranj (Slovenia) were analysed with Raman microspectroscopy to obtain their mineral characteristic, including inclusion assemblage. Most garnets were determined as almandines Type I of pyralspite solid solution series; however, three garnets showed a higher Mg, Mn and Ca contents and were determined as almandines Type II. Most significant Raman bands were determined in the range of 169–173 cm−1 (T(X2+)), 346–352 cm−1 (R(SiO4)), 557–559 cm−1 (ν2), 633–637 cm−1 (ν4), 917–919 cm−1 (ν1), and 1042–1045 cm−1 (ν3). Shifting of certain Raman bands toward higher frequencies was the result of an increase of the Mg content in the garnet composition, which also indicates the presence of pyrope end member in solid garnet solutions. Inclusions of apatite, quartz, mica, magnetite, ilmenite, as well as inclusions with pleochroic or radiation halo and tension fissures (zircon), were found in most of the garnets. Rutile and sillimanite were found only in garnets with the highest pyrope content. Spherical inclusions were also observed in two garnets, which may indicate the presence of melt or gas residues. The determined inclusion assemblage indicates the formation of garnets during medium- to high-grade metamorphism of amphibolite or granulite facies. According to earlier investigations of the garnets from Late Antique jewellery, the investigated garnets are believed to originate from India.
Ključne besede: garnets, inclusions, Sfibulae, Late Antiquity, provenance, Raman microspectroscopy, XRF spectroscopy
Objavljeno v DiRROS: 20.12.2023; Ogledov: 674; Prenosov: 444
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5. Classification of hot-rolled plates using the Mahalanobis distance of NMIs in Ti-stabilized austenitic stainless-steel produced by secondary metallurgyFranci Vode, Franc Tehovnik, Gorazd Kosec, Darja Steiner Petrovič, 2022, izvirni znanstveni članek Ključne besede: stainless steel, ferrotitanium, impurities, oxygen, nonmetallic inclusions, scrap recycling, automated inclusion analysis, Mahalanobis distance
Objavljeno v DiRROS: 06.05.2022; Ogledov: 955; Prenosov: 323
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