Corrosion-resistant Materials

Because of their high nickel alloy content, corrosion-resistant materials have an austenitic crystal lattice in their initial state. In other words, they cannot be quenched and tempered martensitically or bainitically as is done with standard materials. In contrast, corrosion-resistant spring steels obtain their strength by mixed crystal formation, cold hardening during rolling (see DIN 17 224) and by precipitation hardening (X 7 CrNiAl 17 7).

A strength sufficient for springs is achieved only after a certain degree of rolling. Consequently, narrow limits are set for the maximum material thickness of the material. Springs made from corrosion-resistant materials can also be used at extremely low temperatures. By contrast, the strength obtained by cold rolling is lost at temperatures above + 200° C.

X 12 CrNi 17 7 (1.4310)

Chrome-nickel alloy X 12 CrNi 17 7 to DIN 17 224 is commonly used for corrosion-resistant disc springs. This material obtains its strength by cold rolling. The maximum material thickness for disc springs is therefore limited to 2.0 mm. Cold hardening causes a more or less pronounced magnetising of the parts.

X 7 CrNiAl 17 7 (1.4568)

According to DIN 17224, X 7 CrNiAl 17 7 is a precipitation-hardened, corrosion-resistant spring steel. It retains its strength both by cold forming and by precipitation hardening. X 7 CrNiAl 17 7 steel is already very magnetic in the soft state. Cold forming makes the parts even more magnetic.

X 5 Cr Ni Mo 18 10 (1.4401)

Its high corrosion resistance and antimagnetic properties distinguish this steel.

The properties of the materials used by Mubea are listed in the following tables, and can be downloaded here: