| 1. |
- Ericsson, Ola, 1984-
(författare)
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An Experimental Study of Liquid Steel Sampling
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sampling of liquid steel to control the steel making process is very important in the steel industry. However, there are numerous types of disposable samplers and no united standard for sampling. The goal in this study is to investigate the effect of slag protection type and sample geometry on sampling parameters and sample homogeneity. Three sample geometries were selected: i) Björneborg ii) Lollipop with a 6 mm thickness and iii) Lollipop with a 12 mm thickness. These sample geometries have been tested with two types of slag protection: metal-cap-protection and argon-protection. The filling velocity and solidification rate of steel samples have been experimentally measured during plant trials. The sample homogeneity with respect to total oxygen content and inclusion size distribution has been determined in different parts of the samples. The study shows that argon-protected samplers have lower, more even, filling velocities (0.19±0.09 m/s) compared to metal-cap-protected samplers (1.28±2.23 m/s). The solidification rate measurements of the different samplers show that the 6 mm thick Lollipop has the highest solidification rate (99~105 °C/s). Measurements of total oxygen content in argon-protected samples showed little variation between different zones of the samples. However, metal-cap-protected samples contained much higher total oxygen contents. Light optical microscope studies showed that the increase in total oxygen content was probably caused by entrapment of top slag during sampling. Furthermore, it was found that the contamination of top slag in the metal samples increased with a decreased sample weight. Determination of inclusion size distribution in argon-protected Lollipop samples showed that a larger number of primary inclusions are found in the top part compared to the middle and the bottom part of the samples.
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| 2. |
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| 3. |
- Janis, Jesper, et al.
(författare)
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Characteristics of Ti-Ce Complex Deoxidation Products in a Fe-20mass%Cr Alloy
- 2009
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Ingår i: STEEL RES INT. - 1611-3683. ; 80:6, s. 450-456
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Tidskriftsartikel (refereegranskat)abstract
- The particle characteristics such as size distribution, composition and morphology have been studiedin an Fe-20mass%Cr alloy as a function of holding time at 1600°C. The alloy was deoxidised with Tiand Ce, followed by holding at 1600°C and cooling to 1400°C and quenching. The inclusion particleswere investigated on a surface of film filter with an open pore size of 0.05 or 5 μm after electrolyticextraction of the metal samples. Different electric charge and electrolytes (2%TEA and 10%AA) werecompared for extraction of the Fe-20mass%Cr alloy. 300 Coulombs with 10%AA was found mostsuitable for the electrolytic extraction of particles to determine the particle composition and sizedistribution. Most of the particles were found to be complex oxides containing Ti, Ce and Cr.Furthermore, the composition of the particles was found to change from a high Ce-content to a highCr-content with longer holding time at 1600°C.
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| 8. |
- Karasev, Andrey Vladimirovich, et al.
(författare)
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Inhibition of Austenite Grain Growth by Particles and Solute Elements in Fe-0.05% C and Fe-10% Ni Alloys Deoxidized by Mn-Si, Ti, Mg, Zr and Ce
- 2007
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Ingår i: PRICM-6. ; , s. 1055-1058
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Konferensbidrag (refereegranskat)abstract
- The inhibition effect of inclusion particles and soluble elements on the austenite grain growth has been studied in Fe-0.05% C and Fe-10% Ni alloys deoxidized by Mn (1.0%) - Si (0.2%), Ti (0.05%), Mg (0.10%), Zr (0.08%) or Ce (0.12%). It is found experimentally that total surface area of grains per unit volume, which is in inverse proportion to the grain size, increases linearly with increasing the! surface area of particles per unit volume. However, the size of grains in metal with high content of soluble Zr and Ce is significantly smaller than the predicted value from the effect of particle pinning. The additional effect of soluble Zr and Cc on austenite grain growth becomes more significant with an increase of these contents in alloys. An effect of nonrandorn dispersion of particles on grain growth is also estimated and discussed.
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| 9. |
- Karasev, Andrey V., et al.
(författare)
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Nitride Precipitation on Particles in Fe-10 mass % Ni Alloy Deoxidized with Ti, M (M=Mg, Zr and Ce) and Ti/M
- 2009
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 49:2, s. 229-238
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Tidskriftsartikel (refereegranskat)abstract
- The precipitation of nitrides on deoxidation particles in an Fe-10mass%Ni alloy containing 30 similar to 130 ppm O and 14 similar to 22 ppm N has been studied in the experiments where an alloy was deoxidized with Ti, M (M=Mg, Zr and Ce) and Ti/M at 1600 degrees C and then cooled to 1200 degrees C, followed by holding for 0 and 60 min before quenching. The total number of particles above 0.1 mu m remains almost constant except in Ti deoxidation, but the proportion of cubic particles which correspond to nitrides and oxide-nitrides increases during holding at 1200 degrees C in Ti, Zr, Ti/Mg and Ti/Zr deoxidations. In 0.05% (initial amount) Ti deoxidation, the number of TiN and TiN+TiOx particles increases during holding. In 0.03%Ti/0.1%Mg deoxidation, the number of TiOx-TiN particles decreases and the number of MgO-TiN and MgO-Ti(O, N) particles increases during holding due to the reduction of TiOx with soluble Mg. In 0.03%Ti/0.04%Zr deoxidation, the number of ZrO2 particles significantly decreases during holding due to the precipitation of TiN and ZrN on Zr oxides and formation of Zr(O, N)-Ti(O, N) particles. In the cases of Ti/0.08%Zr and Ti/0.12%Ce deoxidations, most of particles at 0 and 60 min of holding are ZrO2 and Zr(O, N) and Ce2O3 oxides, respectively, because the FeO-TiOx oxide in particles is reduced completely by dissolved Zr and Ce.
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| 10. |
- Karasev, Andrey V., et al.
(författare)
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Simultaneous Determination of the Composition and Size of Oxide Particles in Solid Materials by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry
- 2009
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Ingår i: Materials transactions. - 1345-9678 .- 1347-5320. ; 50:2, s. 341-348
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Tidskriftsartikel (refereegranskat)abstract
- Laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used for the determination of the composition and size of oxide particles consisting of SiO2, MnO, Al2O3, MgO and CaO on the surface of a glass or metal sample. The composition and size of multicomponent oxide particles such as MnO-SiO2, CaO-Al2O3 and CaO-Al2O3-MgO evaluated by LA-ICP-MS are compared with those obtained by chemical analysis and by SEM observation. It is confirmed that LA-ICP-MS method has prospects to be applied for quick and simultaneous measurement of the composition and size of particles on the surface of metals in steelmaking industry. The difference between the particle size determined by LA-ICP-MS and that by SEM ranges from 6 to 13% on an average in the range of d(V) = 7 similar to 40 mu m.
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| 11. |
- Sarma, Darbha Subraanranya, et al.
(författare)
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On the Role of Non-metallic Inclusions in the Nucleation of Acicular Ferrite in Steels
- 2009
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 49:7, s. 1063-1074
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Tidskriftsartikel (refereegranskat)abstract
- The effects of non-metallic inclusions in nucleating acicular ferrite in steels during cooling from a weld or cooling from an austenitic temperature are reviewed. The influence of the acicular ferrite (AF) structure on mechanical properties of steels such as strength and toughness is briefly mentioned. The different factors affecting the formation of acicular ferrite, such as the soluble content of alloying elements in steel, cooling rate from austenitizing temperature, austenite grain size and inclusion characteristics in steel, are discussed. The mechanisms of acicular ferrite formation on non-metallic inclusions, such as reduction of interfacial energy, mismatch strain between the inclusion and ferrite/austenite, thermal strains at the inclusions and changes in matrix composition near the inclusions are also discussed. Finally, the effects of inclusion characteristics, such as size, number and composition are described and their effectiveness in nucleating acicular ferrite is discussed.
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| 12. |
- Warne, Mattias, et al.
(författare)
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Size distribution of deoxidation products with Ti, Pr and Ti/Pr in Fe-10mass%Ni alloy
- 2008
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 48:3, s. 310-319
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Tidskriftsartikel (refereegranskat)abstract
- Deoxiclation experiments using Ti, Pr and Ti/Pr have been conducted using a Fe-10mass% alloy at 1 600 degrees C. The purpose of the experiments was to study the change of particle size distribution as functions of holding time, difference between the different deoxidation procedures, and amount of deoxiclant added. The Fe-10%Ni alloy was melted in a induction furnace and Ti, Pr or Ti/Pr were added as deoxidants. Samples were taken at different times after the addition of deoxidants. Thereafter, particles from each sample were extracted using electrolytic extraction. These particles where then examined in a SEM and image analyzer. Results show that the peak height of the size distribution decreases and the modal value increases with an increasing holding time. Furthermore, that the number of particles increases with an increase of deoxidant for a given initial oxygen content and holding time. The size distribution in case of the complex deoxidation using Ti followed by Pr deoxidation was also compared with cleoxiclation using only Pr.
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