Here are 18 types of stainless steel, how many do you know?

Stainless steel is a group of iron alloys containing at least 11% chromium, which inhibits rusting and provides heat resistance. Different types of stainless steel also include elements like carbon (from 0.03% to over 1.00%), nitrogen, aluminum, silicon, sulfur, titanium, nickel, copper, selenium, niobium, and molybdenum. Specific types of stainless steel are often identified by their three-digit AISI designation, such as 304 stainless steel.

Stainless steel can be rolled into sheets, plates, bars, wires, and tubes. It's an ideal material for many applications due to its strength and chromium's corrosion resistance. It can be used in a variety of applications such as cookware, cutlery, surgical instruments (medical bone plates), major appliances, vehicles, building materials in large structures, industrial purposes, and chemical and food storage tanks and tankers.

Stainless Steel Classifications Stainless steel is usually divided into four different groups:

1. Austenitic Stainless Steel: The most common type of stainless steel. It contains higher amounts of chromium, molybdenum, and nickel compared to other types of stainless steel. Known for its adaptability, strength, and ductility.

2. Ferritic Stainless Steel: Contains 10.5% to 30% chromium and typically less than 0.1% carbon. It is magnetic and is preferred for its resistance to temperature, corrosion, and stress corrosion cracking.

3. Duplex Stainless Steel: Combines austenitic and ferritic structures to produce a stronger metal. This combination provides higher strength and weight reduction, with great corrosion resistance, ideal for marine applications.

4. Martensitic Stainless Steel: Structurally similar to ferritic stainless steel, but with higher carbon content (up to 1.2%) allowing significant hardening. Commonly used in making medical tools and surgical instruments.

Stainless Steel Composition

1. 203S: Iron (67.775 – 71.775%), Chromium (17 – 19%), Nickel (8 – 10%), Manganese (2%), Silicon (1%), Carbon (0.15%), Sulfur (0.03%), Phosphorus (0.045%).

2. 301: Iron (70.675 – 74.675%), Carbon (0.15%), Manganese (2%), Phosphorus (0.045%), Sulfur (0.03%), Silicon (1%), Chromium (16 – 18%), Nickel (6 – 8%), Nitrogen (0.10%).

3. 304: Iron (66.74 – 74.5%), Carbon (0.07%), Manganese (2.0%), Silicon (1.00%), Phosphorus (0.05%), Sulfur (0.03%), Chromium (17.50 – 19.50%), Nickel (8.0 – 10.50%), Nitrogen (0.11).

4. 304L: Iron (66.69 – 74.0%), Carbon (0.03%), Manganese (2.0%), Silicon (1.00%), Phosphorus (0.05%), Sulfur (0.02%), Chromium (17.50 – 19.50%), Nickel (8.0 – 10.50%), Nitrogen (0.11).

5. 303S: Iron (67.44 – 71.44%), Chromium (17 – 19%), Nickel (8 – 10%), Manganese (2%), Silicon (1%), Phosphorus (0.2%), Carbon (0.15%), Selenium (0.15%), Sulfur (0.06%).

6. 303Se: Iron (67.44 – 71.44%), Chromium (17 – 19%), Nickel (8 – 10%), Manganese (2%), Silicon (1%), Phosphorus (0.2%), Carbon (0.15%), Selenium (0.15%), Sulfur (0.06%).

7. 316: Iron (61.995 – 69.095%), Carbon (0.08%), Manganese (2.0%), Silicon (0.75%), Phosphorus (0.045%), Sulfur (0.03%), Chromium (16 – 18%), Molybdenum (2.0 – 3.0%), Nickel (10 – 14%), Nitrogen (0.10%).

8. 316L: Iron (62.045 – 69.145%), Carbon (0.05%), Manganese (2.0%), Silicon (0.75%), Phosphorus (0.045%), Sulfur (0.03%), Chromium (16 – 18%), Molybdenum (2.0 – 3.0%), Nickel (10 – 14%), Nitrogen (0.10%).

9. 321: Iron (65.295 – 70.375%), Carbon (0.08%), Manganese (2.0%), Silicon (0.75%), Phosphorus (0.045%), Sulfur (0.03%), Chromium (17 – 19%), Nickel (9.0 – 12.0%), Nitrogen (0.10%), Ti = 5(C+N 0.70%).

10. 347: Iron (64.995 – 69.075%), Carbon (0.08%), Manganese (2.0%), Silicon (0.75%), Phosphorus (0.045%), Sulfur (0.03%), Chromium (17 – 19%), Nickel (9.0 – 12.0%), Nitrogen (0.10%), Nb = 10(C+N 1.0%).

11. 410: Iron (83.53 – 85.53%), Carbon (0.15%), Manganese (1.0%), Silicon (1.0%), Phosphorus (0.04%), Sulfur (0.03%), Chromium (11.5 – 13.5%), Nickel (0.75%).

12. 416: Iron (82.79 – 87.85%), Carbon (0.15%), Manganese (1.25%), Silicon (1.0%), Phosphorus (0.06%), Sulfur (0.15%), Chromium (12 – 14%), Molybdenum (0 – 0.6%).

13. 418: Iron (82%), Chromium (13%), Tungsten (3%), Nickel (2%).

14. 431: Iron (78.23 – 83.75%), Carbon (0.20%), Manganese (1%), Silicon (1%), Phosphorus (0.04%), Sulfur (0.03%), Chromium (15 – 17%), Nickel (1.25 – 2.50%).

15. 440C: Iron (79.15%), Chromium (17%), Carbon (1.1%), Manganese (1%), Silicon (1%), Molybdenum (0.75%).

16. 13-8 PH VAR: Iron (74.122 – 77.35%), Carbon (0.05%), Manganese (0.10%), Silicon (0.10%), Phosphorus (0.010%), Chromium (12.25 – 13.25%), Nickel (7.5 – 8.5%), Molybdenum (2.00 – 2.50%), Nitrogen (0.010%), Aluminum (0.90 – 1.35%).

17. 15-5 PH VAR: Iron (71.91 – 77.71%), Carbon (0.07%), Manganese (1.0%), Sulfur (0.040%), Silicon (1.0%), Chromium (14.0 – 15.50%), Nickel (3.50 – 5.50%), Copper (2.50 – 4.50%), Nb + Ta (0.15 – 0.45%).

18. 17-4 PH: Iron (73%), Chromium (15.0 – 17.5%), Nickel (3.0 – 5.0%), Copper (3.0 – 5.0%), Manganese (1.0%), Silicon (1.0%), Tantalum (0.45%), Niobium (0.45%), Carbon (0.070%), Phosphorus (0.040%), Sulfur (0.030%).