Fatigue Strength of Case Hardened Steel Specimens Containing Through-The-Case Cracks

Business machine components made from steel strip often require case hardened surfaces for adequate wear resistance and/or strength. Straightening operations, following the case-hardening heat treatment, may then be required to produce finished components which conform to flatness or straightness requirements. Subsequent magnetic particle examinations may reveal that the majority or all of the components in a particular order of parts contain cracks. This communication reports an investigation of case hardened specimens containing cracks under conditions of dynamic loading. The study was conducted in an attempt to better understand the behavior of cracked production parts.