Abstract
High-carbon chromium bearing steel tubes rolled in the cold pilger mill were tested in the thrust type rolling contact fatigue testing machine. Their fatigue lives were evaluated as influenced by cold rolling and also by spheroidization at high temperature heat treatment of sulfides elongated during cold rolling. Life of cold rolled tubes with a regular 70% of reduction in area extended more than three times as long as that of hollows and the same cold rolled ones endured over six times more than hollows when heat treated as high temperatures subsequent to cold rolling. It was revealed that nonmetallic inclusions finely dispersed by cold rolling and sulfides spheroidized by high temperature treatment as well contributed to a remarkable improvement in fatigue life of high-carbon chromium bearing steel.
