Abstract
This experiment is also the continuation of former report (V, VI). The results are summerized as follows:
(1) If the heat-treated carbon steel with various C content be pickled, we can find the flakelike or fish-eye-like defects on the fracture of tensile test pieces as the variation of heat treatment.
(2) When high C steel is quenched in water, the flake-like defects are appeared during the pickling, and the appearance is just same as the defect of special steel. But when it is quenched in oil, no defects are appeared during the pickling.
(3) As the tempering temperature of quenched steel become higher, the appearance of defects vary from flake-like to fish-eye-like through cup-like appearance.
