It can be tricky to determine which alloy to choose for an outdoor project. You want the assurance that a stainless steel railing will keep its beauty while staying within budget. Stainless steel performance will vary between alloys. When it comes to corrosion resistance, alloys with a high content of chromium and molybdenum, like alloy 316 and alloy 2205, will perform best but also come at a premium price.