Verification of Charpy-V-impact energy minimum values with subsize test pieces

摘要

For the verification of Charpy-V-impact energy values with test pieces less than 10 mm in width different requirements will be specified in the forthcoming European Standards for steel applications from those in the European technical supply conditions for steels. 10 and 5 mm wide longitudinal and transversal test pieces from 24 alloyed and unalloyed ferritic melts were analysed experimentally in order to determine the correlation between test results obtained from standard test pieces and from subsize test pieces. The conditions for impact energy kV5/kVl0 and data of the temperature shift of the impact strength temperature curve for determined K10 values were the main interest of the investigation. The ratio kV5/KV10 required by the European standards can only be met independently of the test piece orientation under certain conditions: the upper shelf energy must exceed a minimum value. The frequency curves of the individual values show that for outage quantiles of 5 percent, still within the range of acceptance, the proportional conversion of the values of notch impact energy in dependence of the test piece width specified in the European technical supply conditions is technically feasible.