Precipitation of copper particles during pearlite transformation

Masahiro Murakami, Youhei Takanaga, Nobuo Nakada, Toshihiro Tuchiyama, Setsuo Takaki

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    It is known that e-Cu phase precipitates within fcrrite phase independently on ccmcntitc phase in steel. Therefore, Cu addition should be effective for strengthening carbon steels. In this study, Cu was added to Fc-0.8%C eutcctoid alloy up to 2mass% in order to obtain high strength pcarlitic steel. The effect of Cu on pearlitic transformation behavior and the detail of pcarlitic structure were also investigated. First of all, isothermal heat treatment was performed after austenitizing in the Cu bearing eutectoid steels to form pearlitic structure. Microstructural observations revealed that the pcarlitic transformation is significantly retarded by the addition of Cu, while the morphology of pearlite, such as lamellar spacing and block size, arc hardly influenced by the Cu addition. As a result of chemical analysis for the ccmcntitc phase, it was found that the short range redistribution of Cu atoms had been occurred from ccmcntitc to fcrrite through the intcrfacial diffusion at (pearlite / austcnitc) interface during the pcarlitic transformation. The Cu precipitated at the (fcrrite / austcnite) interfaces during pcarlitic transformation as well as within the ferrite phase after the transformation. This resulted in the age hardening during isothermal heat treatment in the eutectoid steel containing 2mass% Cu. The yield strength and tensile strength of the pearlite of Cu bearing eutectoid steels depended on not only lamellar spacing but also the dispersion of Cu particles precipitated in the ferrite phase. The 0.2% proof stress was given by the addition of precipitation strengthening in fcrrite phase to the strength of Cu-free pearlite. For example, the 2mass% Cu addition increases the 0.2% proof stress of pearlitic steel by approximately 250MPa at a maximum.

    Original languageEnglish
    Title of host publicationProceedings of the 17th IFHTSE Congress
    PublisherThe Japan Society for Heat Treatment (JSHT)
    Pages588-591
    Number of pages4
    Volume2
    ISBN (Electronic)9780000000002
    Publication statusPublished - Jan 1 2008
    Event17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008 - Kobe, Japan
    Duration: Oct 26 2008Oct 28 2008

    Other

    Other17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008
    CountryJapan
    CityKobe
    Period10/26/0810/28/08

    All Science Journal Classification (ASJC) codes

    • Surfaces, Coatings and Films
    • Condensed Matter Physics
    • Mechanics of Materials

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