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Tegman, Ragnar
Publications (7 of 7) Show all publications
Nilsson, E., Tegman, R. & Antti, M.-L. (2017). Thermal cycling of grate-link material for iron ore pelletising process (ed.). Ironmaking & steelmaking, 44(4), 269-280
Open this publication in new window or tab >>Thermal cycling of grate-link material for iron ore pelletising process
2017 (English)In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 44, no 4, p. 269-280Article in journal (Refereed) Published
Abstract [en]

A test-rig for thermal cycling has been developed to investigate the mechanisms behind some of the damages done to a grate-link in a pelletising indurator for iron ore pellets. The results from the test-rig were compared with the degradation of grate-links that had been in service for 8 months in the indurator. The damages on the grate-links induced both in the test-rig and at service were defined as internal oxidation which facilitated propagation of intergranular stress corrosion cracking (IGSCC). Internal oxidation was initiated by spallation or removal of the oxide layers. The test-rig was able to successfully perform a lab-scale simulation of the degradation experienced in the indurator. Thermal cycling was applied to plate-formed specimens by constraining their thermal elongation to form bending and thereby stimulate the mechanisms of spallation and sensibilisation to IGSCC by internal oxidation.

Place, publisher, year, edition, pages
Taylor & Francis, 2017
National Category
Other Materials Engineering
Research subject
Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-8244 (URN)10.1080/03019233.2016.1210404 (DOI)000396722800005 ()2-s2.0-84980010123 (Scopus ID)6b903639-c677-4a13-93f4-39130abbb133 (Local ID)6b903639-c677-4a13-93f4-39130abbb133 (Archive number)6b903639-c677-4a13-93f4-39130abbb133 (OAI)
Note

Validerad; 2017; Nivå 2; 2017-03-22 (rokbeg)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-11-19Bibliographically approved
Escalera, E., Garcia, G., Terán, R., Tegman, R., Antti, M.-L. & Odén, M. (2015). The production of porous brick material from diatomaceous earth and Brazil nut shell ash (ed.). Paper presented at . Construction and Building Materials, 98, 257-264
Open this publication in new window or tab >>The production of porous brick material from diatomaceous earth and Brazil nut shell ash
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2015 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 98, p. 257-264Article in journal (Refereed) Published
Abstract [en]

Diatomaceous earth was mixed with Brazil nut shell ash (BNS ash) in different amounts between 0 and 30 wt% and sintered at temperatures between 750 and 950 °C. The BNS ash contains 33 wt% K2O and 11 wt% CaO mainly in carbonate form. The addition of BNS ash into the diatomaceous earth caused significant changes of the microstructure after sintering. The BNS ash addition produces lightweight porous bricks with acceptable strength at lower sintering temperature. The best combination of strength and porosity was achieved for a mixture of 10 wt% of BNS ash in the diatomaceous earth sintered at 850 °C. The achieved high porosity was 49%, density 1.06 g/cm3, thermal conductivity 0.20 W/(m K) and the compressive strength was 8.5 MPa.

National Category
Chemical Process Engineering Other Materials Engineering
Research subject
Chemical Technology; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-3229 (URN)10.1016/j.conbuildmat.2015.08.003 (DOI)000363069800028 ()2-s2.0-84952660413 (Scopus ID)106cc0c1-d578-4d7c-a985-aa36b10f3495 (Local ID)106cc0c1-d578-4d7c-a985-aa36b10f3495 (Archive number)106cc0c1-d578-4d7c-a985-aa36b10f3495 (OAI)
Note
Validerad; 2015; Nivå 2; 20150825 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Escalera, E., Tegman, R., Antti, M.-L. & Odén, M. (2014). High temperature phase evolution of Bolivian kaolinitic–illitic clays heated to 1250 °C (ed.). Paper presented at . Applied Clay Science, 101, 100-105
Open this publication in new window or tab >>High temperature phase evolution of Bolivian kaolinitic–illitic clays heated to 1250 °C
2014 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 101, p. 100-105Article in journal (Refereed) Published
Abstract [en]

The thermal behaviour of two types of clays collected from different locations in Bolivia has been studied. The clays contain kaolinite, illite, quartz and small amounts of microcline. The phase evolutions have been characterized from room temperature to 1250 °C. For both clays, kaolinite is completely transformed into metakaolinite when heated up to 650 °C. During further heating to 1050 °C, illite undergoes total dehydroxylation. Mullite is formed in the temperature interval of 1050–1150 °C and its formation rate is dependent on the amount of K and Fe present in the clays. The clay with higher amounts of K (3.2 mass %) and Fe (5.6 mass%) has an onset temperature for sintering at about 900 °C and an onset temperature for liquid formation at 1080 °C. This is about 50 °C lower onset temperature for sintering and 94 °C lower onset temperature for liquid formation when compared with the clay with lower amounts of K (2.3 mass %) and Fe (1.6 mass %).

National Category
Other Materials Engineering
Research subject
Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-14275 (URN)10.1016/j.clay.2014.07.024 (DOI)000345807700015 ()2-s2.0-84908364184 (Scopus ID)da144151-a7a1-4e52-b8d8-f82ba4c9a0d0 (Local ID)da144151-a7a1-4e52-b8d8-f82ba4c9a0d0 (Archive number)da144151-a7a1-4e52-b8d8-f82ba4c9a0d0 (OAI)
Note
Validerad; 2014; 20140812 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Antti, M.-L., Kero, I., Cheng, Y.-B. & Tegman, R. (2012). Phase reactions in a hot pressed TiC/Si powder mixture (ed.). Paper presented at . Ceramics International, 38(3), 1999-2003
Open this publication in new window or tab >>Phase reactions in a hot pressed TiC/Si powder mixture
2012 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 38, no 3, p. 1999-2003Article in journal (Refereed) Published
Abstract [en]

This work investigated the possibility of producing dense Ti3SiC2 by hot pressing TiC/Si powders. A hot press with graphite heating elements was used for densification and the phase reactions of some hot pressed samples were further evaluated by pressureless heating in a dilatometer. The density and phase composition of the heat treated samples were evaluated using Archimedes principle and by x-ray diffractometry respectively. Hot pressing resulted in a low Ti3SiC2 yield; the main phases were TiC and TiSi2 regardless of starting powder composition, temperature, holding time or pressure. A second heating without pressure resulted in Ti3SiC2 formation, but only in samples initially hot pressed at 1300 °C or lower. At higher hot pressing temperatures, thin oxide layers on particle surfaces were locked into the structure. Acting as diffusion barriers, they prevented the Ti3SiC2 forming reaction. In hot pressed samples the density was significantly higher than in samples sintered without pressure

National Category
Other Materials Engineering
Research subject
Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-11469 (URN)10.1016/j.ceramint.2011.10.034 (DOI)000301611700033 ()2-s2.0-84857061396 (Scopus ID)a72d3a6a-7534-4cbd-b120-b1f29a325823 (Local ID)a72d3a6a-7534-4cbd-b120-b1f29a325823 (Archive number)a72d3a6a-7534-4cbd-b120-b1f29a325823 (OAI)
Note
Validerad; 2012; 20111021 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Engström, A., Mouzon, J., Córdoba, J., Tegman, R. & Antti, M.-L. (2012). Synthesis of a TiCN – SiC polyhedron and elongated crystals nanopowder at low nitrogen concentration (ed.). Paper presented at . Materials letters (General ed.), 81, 148-150
Open this publication in new window or tab >>Synthesis of a TiCN – SiC polyhedron and elongated crystals nanopowder at low nitrogen concentration
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2012 (English)In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 81, p. 148-150Article in journal (Refereed) Published
Abstract [en]

At room temperature diluted TiCl4 and CCl4 were reduced by sodium particles and mixed with a polycarbomethylsilane (PCS) solution to yield a precursor. It was dried and subsequently annealed at 1300 °C, 1400 °C and 1450 °C in a tube furnace using argon with 10 ppm N2. After the 1450 °C annealing a nanocrystalline powder of TiC0.5 N0.5–SiC polyhedron and elongated crystals was obtained. At the low nitrogen concentration during annealing a gradual nitration is proposed. It is promoted by carbon gaseous species, precursor oxidation, a sufficient temperature and a summarised nitrogen surplus compared to the titanium and carbon amount.

National Category
Chemical Process Engineering Other Materials Engineering
Research subject
Chemical Technology; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-12451 (URN)10.1016/j.matlet.2012.04.071 (DOI)000307483300042 ()2-s2.0-84862175981 (Scopus ID)b9adac5a-9bdd-45e9-8b63-8dfea17b4868 (Local ID)b9adac5a-9bdd-45e9-8b63-8dfea17b4868 (Archive number)b9adac5a-9bdd-45e9-8b63-8dfea17b4868 (OAI)
Note
Validerad; 2012; 20120424 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Kero, I., Tegman, R. & Antti, M.-L. (2011). Phase reactions associated with the formation of Ti3SiC2 from TiC/Si powders (ed.). Paper presented at . Ceramics International, 37(7), 2615-2619
Open this publication in new window or tab >>Phase reactions associated with the formation of Ti3SiC2 from TiC/Si powders
2011 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 37, no 7, p. 2615-2619Article in journal (Refereed) Published
National Category
Other Materials Engineering
Research subject
Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-13725 (URN)10.1016/j.ceramint.2011.04.132 (DOI)000293759300078 ()2-s2.0-79960295290 (Scopus ID)d0199b50-2c27-11df-be83-000ea68e967b (Local ID)d0199b50-2c27-11df-be83-000ea68e967b (Archive number)d0199b50-2c27-11df-be83-000ea68e967b (OAI)
Note
Validerad; 2011; 20100310 (idaker)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Nilsson, E. A. A., Tegman, R. & Antti, M.-L.Deposit-induced accelerated corrosion of as-casted ACI HHII stainless steel in a Grate-Kiln indurator.
Open this publication in new window or tab >>Deposit-induced accelerated corrosion of as-casted ACI HHII stainless steel in a Grate-Kiln indurator
(English)Manuscript (preprint) (Other academic)
National Category
Metallurgy and Metallic Materials
Research subject
Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-62156 (URN)
Funder
Hasselblad Foundation, 22875
Available from: 2017-02-24 Created: 2017-02-24 Last updated: 2018-09-05
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