Abstract
Permanent deformation of steel under slowly repeated load of comparatively great magnitude was measured and ε-N or γ-N diagrams and σ-ε or τ-γ diagrams were made where ε and γ denote the strain under tension and torsion respectively, N the number of cycles of repeated load, and σ and τ the axial and the shearing stress separately. Creep tests under normal temperature were also made to compare with the results of present tests under repeated load.
Summary of the results is as follows:
(1) Under repeated load, permanent deformation takes place when stress over yield point was repeated.
(2) Permanent deformations under repeated load and static load were compared; the latter is the larger than the former, but after a definite time the former becomes larger than the latter.
