Browsing by Author "Kilpi, Jaakko"

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  • The effect of post-oxidation on the wear and corrosion resistance of nitrocarburized steel
    (2021-08-24) Kortesmaa, Esa-Pekka
     Kemian tekniikan korkeakoulu | Master's thesis
  • Käyttäjäpersoonien tunnistaminen potilaskeskeisessä sähköisten terveyspalveluiden suunnittelussa
    (2022-09-04) Kilpi, Jaakko
     Perustieteiden korkeakoulu | Bachelor's thesis
  • Typetys vaihtoehtona kovakromaukselle
    (2004) Kilpi, Jaakko
     Helsinki University of Technology | Master's thesis
    The first part of thesis concentrates on the theory behind nitriding and hard chromium plating and their influence on friction, fatigue and corrosion resistance. The nitriding processes used in the experimental part are introduced as well as typical nitriding faults and their prevention through the process control. In the experimental part friction, fatigue and corrosion resistance of nitrided Imanite M and 42CrMo4 steel specimens were compared with hard chromium plated specimens. Corrosion resistance was examined using salt spray tests and a pin-on-disk apparatus was used for friction and fatigue testing. Surface hardness, case and nitriding depths were measured using a Vickers-hardness apparatus. Surface roughness, surface profiles and bearing curves were measured before and after the pin-on-disk tests. Salt spray tests show the influence of base material on the nitriding result and the effect of compound layer porosity on corrosion resistance. The nitriding processes which produce non-porous compound layers had a slightly better corrosion resistance and smaller friction coefficient compared to hard chromium plated specimens. In general differences in friction coefficients between nitrided and hard chromium plated specimens were small.