Stainless Steels Screw is a general referral of the type of material that is used to manufacture the fastener. Generally, carbon steel is not strong enough to withstand long period of harsh weather conditions without any coating.
However, even with a good amount of coating, carbon steel fasteners might still rust in some parts.
That’s the reason why some people require Stainless Steel Screws to properly resist harsher weather conditions.
However, there are some drawbacks to Stainless Steel Screws.
First, the price of stainless cost far more than the usual carbon steel.Although it might help resist rust for a greater period, some places, such as a non-permanent structure, do not need the screws to last as long because it might be torn down within a year.
Second, stainless steel materials are softer than normal carbon steels so it might not be able to penetrate thick metal plates.
This is why Bi-Metal Screws are created to provide it with a carbon steel point to drill through metal, and stainless steel body to withstand harsh weathers.
Stainless Steel Screws are not superior to carbon steel fasteners because they also have it up and downs.