1987 Volume 73 Issue 16 Pages 2290-2297
In order to clarify the characteristics of Induction Heating Quenching and Induction Heating Tempering (IHQIHT) as heat-treating process, micro-structure and mechanical properties of quenched and tempered Si-Cr spring steel (SUP12) by IHQIHT as well as by conventional Furnace Heating Quenching and Furnace Heating Tempering (FHQFHT) were investigated.
(1) Micro-structure of IHQIHT material shows finer grain and less decarburization than those of FHQFHT material.
(2) Ductility, toughness, fracture toughness, resistivity to delayed fracture, resistivity to permanent deformation, and fatigue life of IHQIHT material are superior to those of FHQFHT material. In case of SUP 6, SUP 7, SWRH62B, and S45C, IHQIHT materials show superior toughness generally.
(3) It is presumed that fine grain and retained austenite of IHQIHT material are effective for the above strengthening and toughening. However, unobvious points are still remained, because the influences of short time austenitizing and tempering are intertwisted mutually.