Part of the problem with stainless steel is that it’s not a singular material. It’s an entire galaxy of alloys with a huge range of properties, and some are more corrosion resistant than others. It is certainly possible to concoct some alloy that is for all intents and purposes absolutely rustproof but it’s unlikely to have the other mechanical properties you need for whatever it is you’re doing.
If you’re looking at any object (probably a knife, or maybe a sink or faucet fixture) that simply declares itself “stainless steel” but the manufacturer refuses to admit which alloy even if you press them in a vise, that does indeed usually mean you’re looking at some junk. Low chromium and low nickel stainless alloys are the least corrosion resistant but all other things being equal are also typically the easiest to cut, machine, stamp, or otherwise work into shape.
Part of the problem with stainless steel is that it’s not a singular material. It’s an entire galaxy of alloys with a huge range of properties, and some are more corrosion resistant than others. It is certainly possible to concoct some alloy that is for all intents and purposes absolutely rustproof but it’s unlikely to have the other mechanical properties you need for whatever it is you’re doing.
If you’re looking at any object (probably a knife, or maybe a sink or faucet fixture) that simply declares itself “stainless steel” but the manufacturer refuses to admit which alloy even if you press them in a vise, that does indeed usually mean you’re looking at some junk. Low chromium and low nickel stainless alloys are the least corrosion resistant but all other things being equal are also typically the easiest to cut, machine, stamp, or otherwise work into shape.