I dismantled a retractable dog leash for repair. The spring at the centre was a ribbon of metal, tightly wound (against its “natural” direction) into a coil.
The appearance of the material surprised me; I had expected stainless steel, but it had a distinctive “brassy” yellow surface, highly lustrous and reflective with no trace of tarnish at all, despite being in use for over a year in various conditions.
Is there a steel that looks like this? Or is it possible that the spring is actually a kind of brass?
Another question - is it possible that the alloy includes some beryllium? Or is this only used in tiny springs like watch springs? I was concerned about this because I had heard that if you cut yourself with a beryllium spring, the injury will be very difficult to heal.
In the end (not on the first attempt!) I managed to rewind the spring and reassemble the mechanism without cutting my fingers or putting my eye out.
That makes sense. I guess it is some kind of mild (not stainless) steel.
As for the coating, I’ve looked at cadmium plating on Google Images and it’s about the right colour (although the surface of the spring in question was much more highly polished than the images I saw).
Chromate conversion coating also seems to give a yellow colour, and based on some of the images online, takes a high polish similar to what I saw on the spring.
