Abstract
Five case-hardening steel bars with banded structure were normalized or annealed, from which two kinds of specimens were taken in perpendicular (transverse) and parallel (longitudinal) direction to that of rolling and the directional effect on quenching-deformation of these specimens was studied by means of Carl Zeiss universal-measuring-microscope,and Leitz dilatometer as well as by other metallographic methods. The results obtaind are:—When the annealed specimens were heated at about 900° and quenched in water, the difference of length are markedly observed in two specimens, transverse and longitudinal, while in normalized specimens in which no banded structure is seen,the difference is hardly observable by the same treatment. Such a directional difference in length-change in these test specimens is to some extent reduced in magnitude by slow heating or by preheating prior to quenching. From the result of measurement,it was shown that the directional difference in these specimens depends principally upon the behavior of the change of length in transformation at heating of steels.
