Einfluß des Richtens auf das mechanische Verhalten von Federlegierungen

Influence of Levelling Processes on the Mechanical Behaviour of Spring Alloys Levelling processes – that means straightening of wire or level rolling of strip – have an impairing effect on the R_p0,2 and R_p0,1 proof strength of cold worked spring alloys and on the hysteresis behaviour of flat springs respectively. SEM and TEM investigations indicate that recovery is initiated by levelling processes and is intensified by a subsequent age hardening treatment. This may lead to a modification of age hardening behaviour and effectivity for those alloys which show different age hardening mechanisms in the cold worked and recovered state respectively. The detrimental influence of level rolling on the hysteresis behaviour is found to be due to an increased subgrain size after age hardening treatment. The results show that improvement of geometry by levelling processes is only possible at the cost of decreased spring properties.