Search for dissertations about: "Johan Ahlström"

Showing result 11 - 15 of 16 swedish dissertations containing the words Johan Ahlström.

  2. 11. Microstructure analysis of wear and fatigue in austempered high-Si steels

    Author : Alejandro Leiro; Johan Ahlström; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materialteknik; Engineering Materials; Konstruktionsmaterial; Engineering Materials; Centrumbildning - Centrum för högpresterande stål CHS ; Centre - Centre for High Performance Steel CHS ;

    Abstract : Research on austempering of high-Si steels has increased over the last years due to their attractive combination of strength and toughness. The presence of over 1.5% of silicon prevents the precipitation of cementite during austempering and the resulting microstructure consists of bainitic ferrite and retained austenite. READ MORE

  4. 12. A ΔJ approach for nonlinear fatigue crack propagation : Experimental and numerical investigation of a ductile superalloy

    Author : Daniel Nilsson; Per Almroth; Kjell Simonsson; Björn Sjödin; Daniel Leidermark; Sören Sjöström; Fredrik Borén; Johan Ahlström; Linköpings universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ΔJ; Cyclic J-integral; Fatigue testing; Nickel-based superalloy; Thermo-mechanical fatigue; Elasto-plastic fracture mechanics;

    Abstract : This dissertation is a product of an academic-industrial collaboration between the Division of Solid Mechanics at Linköping University and Siemens Energy AB. The focus is on enhancing the design optimisation procedures for high-temperature components in industrial gas turbines (IGT). READ MORE

  5. 13. On deoxidation practice and grain size of austenitic manganese steel

    Author : Dimitrios Siafakas; Anders Jarfors; Taishi Matsushita; Johan Nils Ahlström; Jönköping University; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hadfield steel; deoxidation; grain size; inoculation; particles; carbides; oxides; Hadfield stål; desoxidering; kornstorlek; ympning; partiklar; karbider; oxider;

    Abstract : The exceptional wear resistance and work hardenability, place Hadfield steel as one of themost important materials for manufacturing cast components used in the mining, crashing,drilling, and excavation industries. In all metallic alloys used for component casting, themechanical properties are highly influenced by the microstructure of the material. READ MORE

  6. 14. High-Temperature Corrosion-Fatigue of Cast Alloys for Exhaust Manifolds

    Author : Shengmei Xiang; Joakim Odqvist; Baohua Zhu; Johan Ahlström; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High temperature; corrosion fatigue; low-cycle fatigue; cast alloys; high-temperature oxidation; intermetallic phase; Teknisk materialvetenskap; Materials Science and Engineering;

    Abstract : The introduction of gas-driven Otto engine and the corresponding usage of bio-fuels in heavy-duty engines will render the exhaust atmosphere more corrosive and bring a higher working temperature to exhaust manifolds. The current service material, a ferritic ductile cast iron called SiMo51, will soon meet its upper temperature limit set by the ferrite-austenite transformation at 860ºC. READ MORE

  7. 15. Oxidation, Creep and Fatigue Synergies in Cast Materials for Exhaust Manifolds

    Author : Shengmei Xiang; Joakim Odqvist; Baohua Zhu; Stefan Jonsson; Johan Ahlström; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fatigue; low-cycle fatigue; fatigue in an inert atmosphere; fatigue in a synthetic diesel exhaust atmosphere; corrosion-fatigue; creep-fatigue; high-temperature corrosion; high-temperature fatigue; synergistic effect; corrosion-fatigue synergy; creep-fatigue synergy; high-temperature alloys; fatigue damage; creep-fatigue damage; corrosion-fatigue damage; ductile cast iron; high-alloyed austenitic cast steel; thermal cycling; precipitation; aging.; Teknisk materialvetenskap; Materials Science and Engineering;

    Abstract : The future development of engines of heavy-duty vehicles towards reduced CO2 emission will increase the exhaust gas temperature and render the exhaust atmosphere more corrosive. The current service material of exhaust gas components - a ferritic ductile cast iron called SiMo51 - will soon meet its upper-temperature limit. READ MORE