Due to the in-service stress corrosion cracking of some 3-1/2NiCrMoV steam turbine disks, the Charpy V-notch toughness requirements for replacement forgings have dramatically increased in recent years. In response to the new requirements, several avenues for improving the toughness of 3-1/2NiCrMoV steel have been explored and are discussed in this paper. Improvements in forging practice, preliminary heat treatment, final heat treatment and composition are recommended which allow the new requirements to be met.

This content is only available via PDF.
You do not currently have access to this content.