Process-temperature Control Rings as a Tool for Characterizationof the Sintering Process

摘要

Process temperature control rings are recommended for checking the temperature of heatrntreatment processes a posteriori, the temperature reading being obtained from the shrinkagernduring the heat treatment process through data sheets supplied for each batch of rings. Herernit is shown through dilatometric studies that in fact these rings are not indicating the sinteringrntemperature but the ,,sintering intensity“. In addition to the isothermal temperature, also thernsoaking time and the heating/cooling rates play a major role while the atmosphere is lessrnrelevant. The temperature reading agrees with the listed data only at slow heating andrncooling and rather long soaking times, conditions that are common in ceramic firing ratherrnthan in PM. In any case, however, the rings are well suited for checking the reproducibility ofrnthe sintering effect for PM precision parts.