Helsinki University of Technology Department of Mechanical Engineering Laboratory of Engineering Materials EFFECTS OF NON-METALLIC INCLUSIONS ON FATIGUE PROPERTIES OF CALCIUM TREATED STEELS Pekko Juvonen Dissertation for the degree of Doctor of Science in Technology to be presented with due permission for public examination and debate in Micronova (Large seminar room) at Helsinki University of Technology (Espoo, Finland) on the 10 th of December, 2004, at 12 o’clock noon. Espoo 2004