It doesn't always have to be stainless steel. This is the result of extensive HUMMEL AG salt spray tests. Based on these tests, a surface treatment for circular connectors was developed, which comes properties of stainless steel. Meanwhile, M23 connectors with chromated surfaces are used for connection solutions on construction machinery.
Outdoor applications are exposed to many adversities: vibrations, shocks, heat, cold, sunlight or moisture. Especially the corrosion protection is of particular importance. In connection technology connectors made of stainless steel are often used in such cases. However, the requirements cannot always be met with stainless steel components. Cost aspects or the desire for a special geometry (e.g. a quick-release fastener)
A cost-effective alternative to the stainless steel connector is the variant with a black chromate coating. Extensive tests have shown that this surface coating is far more resistant to corrosion than conventionally nickel-plated surfaces. The chromate coating comes very close to stainless steel and thus becomes an attractive alternative for numerous applications. Another plus point: the black
chromated zinc die-cast connector is also available also available in the quick-lock versions TWILOCK and TWILOCK-S.
Black chromated connectors offer numerous advantages and are an attractive
alternative to stainless steel for many applications.