Search for dissertations about: "carburization"

Showing result 6 - 10 of 16 swedish dissertations containing the word carburization.

2. 6. Critical Aspects of Delubrication and Sintering of Chromium-alloyed Powder Metallurgy Steels

   Author : Seshendra Karamchedu; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; delubrication; oxide reduction; surface oxide; carbon control; sintering atmosphere; chromium-alloyed sintered steels;

   Abstract : The cost efficiency and performance of Powder Metallurgy (PM) steels can be improved by replacing conventionally used alloying elements such as copper and nickel with chromium. Utilizing chromium imposes a challenge in terms of processing due to its effect on powder compressibility and high oxygen affinity, the latter of which, to a certain extent, is dealt with by introducing chromium in prealloyed form that decreases its activity. READ MORE

4. 7. Processing of Nanostructured WC-Co Powders and Sintered Steels

   Author : Zongyin Zhang; KTH; []
   Keywords : Nanostructured powder; Chemical synthesis; Fe-Mn-Si steel; Fe-Cu swelling; Mechanical properties; Sintering parameters;

   Abstract : Processing of nanostructured WC-Co and W-Co powders,modelling of Fe-Mn-Si alloy, swelling of Fe-Cu alloy, andmechanical properties and sintering of Fe-Mn-Si steels havebeen studied in the present thesis.W-Co precursors made by chemical synthesis were used toproduce nanostructured WCCo and W-Co powders by calcination,reduction and carburization. READ MORE

5. 8. Fundamental studies on the high temperature corrosion mechanisms of a 22Cr austenitic stainless steel in environments related to oxy-fuel combustion

   Author : Luciana Intiso; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; EDX; TEM; KCl; Na2SO4; SEM; FIB; high temperature oxidation; sulphur dioxide; carbon dioxide; GI-XRD; stainless steels; water vapour; GDOES; t-EBSD;

   Abstract : This thesis concern the high temperature corrosion mechanisms of stainless steels, with focus on a 22 wt.% Cr FeNiCr alloy (Sanicro 25), in environments related to oxy-fuel combustion, which is a promising technology that can provide enhanced CO2 recovery and sequestration from power plants by using post-combustion capture. READ MORE

6. 9. Degradation Mechanisms of Heat Resistant Steel at Elevated Temperatures : In an Iron Ore Pelletizing Industry

   Author : Erik A. A. Nilsson; Marta-Lena Antti; Ragnar Tegman; Jan-Erik Svensson; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; stainless steel; Grate-Kiln; microstructure; corrosion; as-casted; thermal cycling; erosion; deposition; Engineering Materials; Materialteknik;

   Abstract : This thesis focuses on the different degradation mechanisms of the stainless steel in a travelling grate in a Grate-Kiln iron ore pellet indurator. The travelling grate is a conveyor belt that transports green-body pellets to a rotary kiln while the pellets are being dried and pre-heated to a temperature of 900-1100 °C by recycled hot air. READ MORE

7. 10. Some aspects of convection as well as graphite and carbide formations during casting

   Author : Fareed Ashraf Khan; Michael Vynnycky; Pär Jönsson; Bo Rogberg; Hasse Fredriksson; Jessica Elfsberg; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; carbides; heat treatment; cast iron; ball bearing steel; casting; cooling rate; structure analysis; nodule distribution; melt stirring; nuclei; karbider; värmebehanding; gjutjärn; kullagerstål; gjutning; kylningshastighet; strukturanalys; nodulefördelning; smältrörelse; kärnor.; Metallurgical process science; Metallurgisk processvetenskap;

   Abstract : It is an established fact that segregation during casting affects the physical properties of carbon-based ferro alloys; this motivates the study of the segregation behaviour of carbon and carbide-forming solute elements. In this context, this thesis investigates two different situations: the effects of cooling rate and turbulence on the precipitation behaviour of the graphite nodules in nodular cast iron; the nature of carbide precipitation in a bearing steel grade and the effects of subsequent soaking on these carbides. READ MORE