| 1. |
- Ekengård, Johan, 1976-
(författare)
-
Slag/Metal Metallurgy in Iron and Steel Melts
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this work, the metal and slag phase mixing in three steps of a ladle refining operation of steel melts and for an oxygen balance during cooling of cast iron melts have been studied at two Swedish steel plants and at two Swedish cast iron foundries, respectively. In order to predict the oxygen activity in the steel bulk in equilibrium with the top slag as well as in metal droplets in the top slag in equilibrium with the top slag, three slag models were used. In addition, the assumptions of a sulphur-oxygen equilibrium between steel and slag and the dilute solution model for the liquid steel phase were utilized in the calculations. Measured oxygen activities in steel bulk, which varied between 3.5-6 ppm, were compared to predicted oxygen activities. The differences between the predicted and measured oxygen activities were found to be significant (0-500%) and the reasons for the differences are discussed in the thesis. Slag samples have been evaluated to determine the distribution of the metal droplets. The results show that the relatively largest numbers of metal droplets are present in the slag samples taken before vacuum degassing. Also, the projected interfacial area between steel bulk and top slag has been compared to the interfacial area between the metal droplets and slag.The results show that the droplet-slag interfacial area is 3 to 14 times larger than the flat projected interfacial area between the steel and top slag. Furthermore, the effect of the reactions between top slag and steel and the slag viscosity on the metal droplet formation is discussed. The results show significant differences between the steel bulk and steel droplet compositions and the reasons for the differences are discussed in the thesis. The oxygen activity in different cast irons was studied. Plant trials were performed at three occasions for lamellar, compacted and nodular iron melts. The results show that at temperatures close to the liquidus temperature the oxygen activities were 0.03-0.1 ppm for LGI, around 0.02 ppm for CGI, and 0.001ppm for SGI. In addition, it was found that as the oxygen activities increased with time after an Mg treatment, the ability to form a compact graphite or a nodular graphite in Mg-treated iron melts was decreased. Also, extrapolated oxygen activity differences up to 0.07 ppm were found for different hypoeutectic iron compositions for lamellar graphite iron at the liquidus temperature. Overall, the observed differences in the dissolved oxygen levels were believed to influence how graphite particles are incorporated into the austenite matrix and how the graphite morphology will be in the cast product.
|
|
| 2. |
- Magnelöv, Marianne, et al.
(författare)
-
Investigation of iron losses during desulphurisation of hot metal utilising nepheline syenite
- 2013
-
Ingår i: Ironmaking & steelmaking. - 0301-9233 .- 1743-2812. ; 40:6, s. 436-442
-
Tidskriftsartikel (refereegranskat)abstract
- Iron losses during calcium carbide based hot metal desulphurisation have been studied via large scale investigations of slag from the slag pit as well as slag sampling during desulphurisation at SSAB EMEA in Luleå. The desulphurisation slag, after injection of calcium carbide, is normally solid and contains large amounts of iron. An alkali containing mineral, nepheline syenite, was mixed together with the calcium carbide to form a more fluid slag as the iron losses originate from enclosed metal droplets in the slag as well as drawn off hot metal during slag skimming. The slag amount after slag skimming decreased from 28.1 to 25.1 kg t-21 hot metal with addition of 5 wt-% nepheline syenite to the calcium carbide, and the magnetic fraction of the slag from the slag pit decreased from 2.5 to 1.9%. Finally, no negative effect on the reagent efficiency was observed during the trials with addition of nepheline syenite.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Beskow, Kristina, et al.
(författare)
-
A new approach for the study of slag-metal interface in steelmaking
- 2006
-
Ingår i: Ironmaking & steelmaking. - : Informa UK Limited. - 0301-9233 .- 1743-2812. ; 33:1, s. 74-80
-
Tidskriftsartikel (refereegranskat)abstract
- The main focus of the present work was to develop a sampler to obtain the physical description of the slag-metal interface in the presence of bulk flow. Industrial trial experiments were carried out in the ladles at Uddeholm Tooling, Hagfors, Sweden using the designed sampler. Samples of the slag-metal interface were successfully taken in both gas stirring and induction stirring modes. The similarities of the appearance as well as the micrographs of the samples suggested that the slag-metal interfaces in the two stirring modes were very similar except in the open eye area. In the case of both stirring modes, metal droplets were found in the slag bulk. On the other hand, no appreciable amount of slag was detected in the metal bulk. Further systematic investigation using a large number of samples is required to obtain a quantitative description of the interface.
|
|
| 6. |
- Beskow, Kristina, et al.
(författare)
-
A new approach for the study of slag-metal interface in steelmaking
- 2006
-
Ingår i: Ironmaking & steelmaking. - 0301-9233 .- 1743-2812. ; 33:1, s. 74-80
-
Tidskriftsartikel (refereegranskat)abstract
- The main focus of the present work was to develop a sampler to obtain the physical description of the slag-metal interface in the presence of bulk flow. Industrial trial experiments were carried out in the ladles at Uddeholm Tooling, Hagfors, Sweden using the designed sampler. Samples of the slag-metal interface were successfully taken in both gas stirring and induction stirring modes. The similarities of the appearance as well as the micrographs of the samples suggested that the slag-metal interfaces in the two stirring modes were very similar except in the open eye area. In the case of both stirring modes, metal droplets were found in the slag bulk. On the other hand, no appreciable amount of slag was detected in the metal bulk. Further systematic investigation using a large number of samples is required to obtain a quantitative description of the interface. © 2006 Institute of Materials, Minerals and Mining.
|
|
| 7. |
- Björkvall, Ander, et al.
(författare)
-
Slutrapport Anslagstavlan - Forskarfredags massexperiment 2016 : VA-RAPPORT 2017:1
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vad används anslagstavlor till nuförtiden? Detta vet vi mycket lite om, framför allt för att det är så svårt att samla in informationen. För att kunna forska om anslagstavlor tog vi därför hjälp av 46 skolklasser i ForskarFredags massexperiment. Med en mobil- app samlade eleverna in text och fotografier från anslagstavlor i hela landet! Efter att ha gallrat bort bilder som var alltför suddiga eller inte var tagna på rätt sätt hade vi sammanlagt 1 340 bilder som gick att använda i vår forskning. De flesta anslagen har satts upp av föreningar. Därefter kommer företag. På tredje plats kommer privatpersoner. Endast en liten andel av de insamlade anslagen (6 procent) innehåller text som skrivits för hand med penna, resten är gjorda med dator. Mer än en tredjedel av anslagen är inbjudningar (37 procent). Det kan till exempel handla om konserter, möten, föredrag och firanden. Lika vanligt är det med köp- och säljannonser av varor och tjänster. Bland de insamlade anslagen finns fem cykelan- nonser. Alla dessa är korthuggna och opersonliga. Bostadsannonserna, däremot, är mer personliga och detaljrika. Anslag som handlar om lärande och utbildning gäller ofta lokala platser. Lärandet äger alltså rum i närområdet snarare än på ställen dit deltagaren måste resa långt, gå ut på internet eller till och med flytta för att kunna delta. Trots att det finns väldigt många människor med utländsk bakgrund i Sverige är näs tan alla anslag på svenska. Bara knappt 5 procent har skrivits helt eller delvis på andra språk. Men vi kan ändå se att engelska har en viktig roll i texter i vår omgivning.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
