Stress relieved grinding rod having hard outer shell

摘要

A grinding rod having a hardened outer shell of tempered martensite is adapted for use in heavy duty grinding environments. The rod is stress relieved to reduce internal compressive stresses in the tempered martensitic shell to less than 60 ksi and greater than 15 ksi. Such stress relieve stabilizes the rod against break-up as caused by the balancing tensile stresses in the pearlitic core exceeding tensile strength of the core.