The influence of strain rate and strain on the behavior of stress relaxation in 980 MPa-grade dual phase steel sheets

Kodai Murasawa, Hayato Komine, Yoshie Otake, Hideyuki Sunaga, Masato Takamura, Yoshimasa Ikeda, Shinsuke Suzuki

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

    2 Citations (Scopus)

    Abstract

    The specimens (980 MPa-grade dual phase steel sheets) were stretched until the pre-defined strain was obtained. Then the specimens were held at the pre-defined strain and measured the change of stress during holding. We investigated the effects of strain rate and strain at the starting time of holding and whether the stress change during holding could be described by Krempl model. The following results were obtained. First, the stress drop increased with increase of strain rate and the holding time. On the other hand, the stress drop was not affected by strain change at the starting time of holding. Second, initial stress relaxation rate increased with increase of strain rate. However, this strain rate dependency to stress relaxation rate diminished as the holding time became long enough roughly more than 100 s. Third, the stress change during holding obtained by Krempl model accurately agreed with experimental result. It was found that the stress change during holding could be well described by using Krempl model. This suggests that dislocation moves viscously. In addition, the strain rate dependency on stress change during holding could be described by change of the parameter A.

    Original languageEnglish
    Title of host publicationMetal Forming 2016
    PublisherTrans Tech Publications Ltd
    Pages948-953
    Number of pages6
    Volume716
    ISBN (Print)9783038357049
    DOIs
    Publication statusPublished - 2016
    Event16th Metal Forming International Conference, 2016 - Krakow, Poland
    Duration: 2016 Sep 182016 Sep 21

    Publication series

    NameKey Engineering Materials
    Volume716
    ISSN (Print)10139826

    Other

    Other16th Metal Forming International Conference, 2016
    CountryPoland
    CityKrakow
    Period16/9/1816/9/21

      Fingerprint

    Keywords

    • High-Strength Steel Sheet
    • Stress Relaxation
    • Stress-strain Relationship
    • Viscoelasticity
    • Viscoplasticity

    ASJC Scopus subject areas

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering

    Cite this

    Murasawa, K., Komine, H., Otake, Y., Sunaga, H., Takamura, M., Ikeda, Y., & Suzuki, S. (2016). The influence of strain rate and strain on the behavior of stress relaxation in 980 MPa-grade dual phase steel sheets. In Metal Forming 2016 (Vol. 716, pp. 948-953). (Key Engineering Materials; Vol. 716). Trans Tech Publications Ltd. https://doi.org/10.4028/www.scientific.net/KEM.716.948