scope:

The development of the material toughness rules, i.e. required CVN, impact test exemption curves, and the additional reduction in the impact test temperature based on loading condition incorporated into the new ASME Section VIII Division 2, 2007 Edition is covered in this bulletin. Changes to the toughness rules in earlier version of this code were necessitated by increased allowable stresses under that ASME Code and the need for corrections as discovered by a comprehensive review of the past practices and assumptions. A new correlation that determines the required Charpy V-Notch impact energy (CVN) from the fracture toughness is also documented and a methodology to relate this energy to both the dynamic and static fracture toughness using the model is also described