Sökning: "Hot cracks"

Visar resultat 1 - 5 av 39 avhandlingar innehållade orden Hot cracks.

  1. 1. Closed-die forging and slab hot rolling with focus on material yield : some industrial problems analysed by FEM

    Författare :Esa Ervasti; Ulf Ståhlberg; Hans Keife; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material yield; Closed-die forging; Hot rolling; Cracks; Macro-inclusions; Steel; FEM; Industrial engineering and economy; Industriell teknik och ekonomi;

    Sammanfattning : The thesis is focussed on improving the material yield in closed-die forging and rolling. The former is restricted to the manufacturing of heavy crown wheels and front axle beams and the latter to the hot rolling of steel slabs. To enhance the yield the commercial FE-codes Form2D and Dyna3D are used. LÄS MER

  2. 2. Hot Cracking and Grain Boundary Weaknesses of Nickel - Based Superalloys

    Författare :Joel Håkan Andersson; Chalmers University of Technology; []
    Nyckelord :Hot cracks; Notch rupture testing; Eutectic; Weldability; Varestraint testing; Grain boundary weaknesses; Superalloys;

    Sammanfattning : Abstract Grain boundary weaknesses of nickel-based superalloys not only materialize during service in the hot turbine engine sections but also during the weld manufacturing. The performance, in this respect, of the most commonly used alloys at Volvo Aero Corporation (VAC), 718 and the higher temperature capacity Waspaloy, are therefore the main subjects for this thesis. LÄS MER

  3. 3. On the hot crack formation during solidification of iron-base alloys

    Författare :Karin Hansson; KTH; []
    Nyckelord :hot cracking; hot tearing; cracking fracturing ; tearing; ductility; brittleness; embrittlement; fractures; ductile brittle transition; solidification; iron; copper; nickel; Invar; steels; free machining steels; stainless steels; penetration; crack;

    Sammanfattning : Hot cracking during solidification is a severe problem inmany casting processes, for example in continuous casting.Combinations of low strength and low ductility of the materialat high temperatures and applied tensile stress can cause hotcracking. LÄS MER

  4. 4. Life Prediction and Mechanical Behavior of Thermal Barrier Coatings

    Författare :Yan Liu; Materialteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stress intensity factors; Macro-cracks; Micro-cracks; Mechanical behaviour; Thermal barrier coatings; Life prediction; Material technology; Materiallära; materialteknik;

    Sammanfattning : Delamination and spallation of thermal barrier coating (TBC) systems, used in hot parts of gas turbines, have been studied with respect to thermal fatigue. TBCs with and without pre-existing cracks were investigated. Thermal shock tests were performed until coating spallation. LÄS MER

  5. 5. Continuous Fibre Reinforced Oxide/Oxide Composites

    Författare :Magnus Holmquist; Chalmers University of Technology; []
    Nyckelord :polycrystalline oxide fibre; zirconia; single crystal oxide fibre; hot isostatic pressing; hot pressing; alumina; mullite; sapphire; tape casting; interface; VibroIntrusion; interphase; continuous fibre reinforced ceramic composite; mechanical properties; oxide fibre; ceramic matrix composite;

    Sammanfattning : The appealing properties of ceramics include retention of strength and hardness at high temperatures, chemical inertness and low density. However, monolithic ceramics fail in a brittle, unpredictable manner making them unsuitable for many applications where reliability is a key requirement. LÄS MER