Stainless Steel Types:
- Type 304: This is the most common grade of stainless steel and is widely used for many applications. Contains approximately 18% chromium and 8% nickel.
- Type 304L: Similar to 304 except that is has very low carbon content (“L” represents low carbon). This improves the corrosion resistance of welds by reducing carbide precipitation during welding.
- Type 316: The addition of 2–3% molybdenum gives 316 better overall corrosion resistance for certain applications compared to 304.
- Type 409: This is a lower-cost stainless with approximately 11% chromium. A light surface rust will form in most atmospheres; this rust retards further corrosion.
Stainless Steel Finishes:
- No. 2B: Also called mill finish, this is the standard cold-rolled finish and is a uniform matte gray in appearance.
- No. 3: This is a ground unidirectional uniform finish obtained with 80–120 grit abrasive. Also called “brushed”.
- No. 4: This is a ground unidirectional finish, similar to a number 3, but using finer 150–180 grit abrasive. Can also be called “brushed” or sometimes “satin”.