Abstract
The present work has dealt with the torsion creep behavior and the torsion creep strength at moderate temperatures of quenched and tempered hot-work die steel (SKD5), high speed steel (SKH2) and JIS spring steel (SUP6) which were used for high-temperature spring material. Torsion creep test were carried out on 5mmφ solid cylindrical specimen at 15°, 300° and 400°C under a stress of 12∼45% of static torsional strength.
In the case of 150°C of SUP6 and 300°C of SKD5, creeping did not proceed after about 300 hours, but at 300°C of SUP6 and SKH2 and 400°C of SKD5 and SKH2 creeping was continued even after 400 hours with decreasing the creep rate. The torsion creep strength for a strain of 0.03% in 100 hours of 300°C of SKD5 was 28kg/mm2, and for 400°C was 23kg/mm2. For 300°C of SKH2 was 41kg/mm2, and 18kg/mm2 for 400°C. And also, for 150°C and 300°C of SUP6 were 34kg/mm2 and 16kg/mm2, respectively.
