Indirect Verification of Pendulum Impact Testing Machines: The French Subsidiary from Its Origins to the Present, Changes in Indirect Verification Methods, Effects on Dispersion, and Perspectives

A straightforward method of checking pendulum impact testing machines was developed at the end of the 1970s at the request of French industrialists. This method was based on the use of reference test pieces to compare the energy provided by a reference machine with that of test (or industrial) machines. These principles are outlined in French standard NFA 03-508 and France had a national source of unnotched, reference test pieces. The manufacture of reference test pieces, characterization of calibrated batches and the indirect verification of industrial machinery therefore have been practised for twelve years or so.

Various European studies and changes in standardisation protocols have led to the replacement of unnotched test pieces by Charpy notched test pieces. France developed a source of reference test pieces of this type in the early 1990s. The French system, which is based on a partnership comprising the Fédération Française de l'Acier (French Steel Federation), steelmakers Aubert and Duval, and national laboratories (CTA and LNE), has been in operation since European standard EN 10 045-2 was first applied in 1993. Experience together with discussions between partners and users has led to considerable advances in the processes used to manufacture these test pieces, thus improving the dispersion obtained. The quality situation, especially accreditation procedures implemented by national organisations such as COFRAC (Comité Français d'Accréditation — French Accreditation Comity), has also contributed to advances in perfecting methods and assessing approximations.