ばね鋼の燒入燒もどし, オーステンパーおよびマルテンパーアンドテンパーについて  [in Japanese] Quench & Temper ; Austemper and Martemper & Temper of Spring Steel  [in Japanese]

The authors compared the subject three kinds of heat-treatment on plain carbon spring steel SUP-3,Si-Mn spring steel, and SUP-6 which are commonly used as leaf springs of railway cars and motor vehicles, by measuring hardness, impact strength permanent set due to bending test, and micro-structure, and particularly investigated toughness. They also examined the mechanical properties on the relation between size of specimen and isothermal transformation. By comparing the toughness with notched bar impact Strength and bending Strength with nearly same range of hardness, the best result was obtained with austempering. When Si-Mn spring steel is treated, it is not difficult to get bainite structure, while with plain carbon spring steel, we may be not able to get bainite structure unless the specimen is very thin.