Abstract
In the present paper, the microstructure of recently developed non-magnetic austenitic spring steels of high strength is described and correlated to mechanical behaviour.
It is possible to combine a high strength with a low magnetic permeability. This is achieved by a balanced alloying with strong austenite forming elements such as Ni, Mn and N.
Further strengthening occurs as a result of precipitation hardening during tempering. The strong tempering response in Si-rich alloys is ascribed to enhanced precipitation, which is in part explicable by the ability of Si to increase the activity of C. In V-rich steels, the strong tempering effect is most likely caused by VN precipitation.
A low magnetic permeability is achieved essentially by alloying with the strong austenite stabilizing elements Ni, Mn and N. Owing to the suppression of magnetic α-martensite a low magnetic permeability is maintained even after severe cold working.
