Beer kegs have a high amount of steel in them, the reason for this is they are a pressure vessel and if they were made from just stainless and you over loaded them they would shatter but with the steel they just split.
NO
what im saying is that beer kegs have alot more steel in them than other stainless products so if you damage the surface they will rust, because alot of people think that they are bullet proof.
Mate, you sound a bit confused here.
Steel is an alloy of iron with a small amount of carbon.
Stainless steel is steel that has Nickel and Chrome added which forms a tough oxide layer that prevents the iron from rusting. Embed iron in your stainless steel surface and it will start to rust allowing the underlying metal to also rust.
HTH,
David