Sales-zoid horse pucky!
Stainless steel commercial and residential plumbing components are made of 300 series stainless which is called 18/8 outside the US. That means 18% chrome and 8% nickel with a low carbon content (0.15% down to 0.1%).
The corrosion resistance comes mostly from the chrome content with nickel adding some additional benefits.
The percentages of alloy vary depending on the specific grade of 300 SS from 16%-21% Cr and 6%-10% Ni nominal. Plumbing fixtures are usually made of plain vanilla 302 or 303 SS because they are easy to form and offer adequate corrosion resistance to all but the strongest chemicals.
These kinds of stainless steels can only be hardened through cold working - rolling, drawing, forming etc.
There are other "families" of stainless steel that can have higher carbon content but they are not used in the plumbing industry.
Chas. Colerich Oakland, CA USA
Carlos Ovalle wrote:
> When I was on the market for stainless-steel kitchen accessories for a commercial project, a sales representative explained that the higher the carbon content, the stronger but less rust-resistant stainless steel becomes. He also said something about the content of nickel in the mix, where nickel will make the stainless steel more stainless but more expensive.
> Carlos Ovalle
> Long Beach, California, USA