EXPOSITTON OF THE STRAIN-AGE-HARDENING PROBLEM OF THE MILD STEEL (I)

The strain-age-hardening problem of the mild steel is as important in practice as in laboratory. The yield-point-jog appears in ordinary mild steel, its disappearance of after cold work and its reappearance on aging after cold work are the typical characters of this problem. Therefore, a great deal has been investigated on this problem and recently interest has been increased by the confirmations that the both C-& N-atoms in the mild steel play a leading role in this phenomena and aging effects can be minimized by a drastic deoxidation. In this paper, the author will try to introduce the representative three theories about the problem, that is, the skelton theory, the transformation theory and the dislocation theory.