Proposed Changes to Charpy V-Notch Machine Certification Requirements

In 1989 the administration of the Charpy V-Notch Certification Program was assumed by the National Institute of Standards and Technology. The United States Army originated the program to insure the measurement integrity of Charpy V-notch machines across the country. The program has been operated for many years using candidate machine acceptance limits which can possibly be traced to a 1955 paper by Driscoll, however, the original statistical justification for using these acceptance criteria has been lost or never existed. A statistical analysis of recent certification program data indicates that the existing candidate machine acceptance limits should be modified. In this paper, we will discuss and justify potential changes to candidate machine acceptance limits.