304 Stainless is a low carbon (0.08% max) version of basic 18-8 also known as 302. Type 302 has 18% chromium and 8% nickel. Type 304 has slightly lower strength than 302 due to its lower carbon content. Type 304 finds extensive use in welding applications because the low carbon permits some exposure in the carbide precipitation range of 800°F - 1500°F without the need for post-annealing operations. However, the severity of corrosive environments may necessitate annealing after welding or the use of 304L.
Type 304L has a carbon content of 0.03% or less. This alloy can be used in the as-welded condition without becoming susceptible to intergranular corrosion.
| Chemical Composition | ||||||||
| Grade | C max | Si max | Mn max | P max | S max | Ni | Cr | Mo |
| TP 304 | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 8--11 | 18--20 | |
| TP 304H | 0.04-0.10 | 0.75 | 2 | 0.04 | 0.03 | 8--11 | 18--20 | |
| TP 304L | 0.035 | 0.75 | 2 | 0.04 | 0.03 | 8--13 | 18--20 | |
| TP 309S | 0.08 | 0.75 | 2 | 0.045 | 0.03 | 12--15 | 22--24 | |
| TP 310S | 0.08 | 0.75 | 2 | 0.045 | 0.03 | 19--22 | 24--26 | 0.75 max |
| TP 316 | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 10--15 | 16--18 | 2--3 |
| TP 316L | 0.035 | 0.75 | 2 | 0.04 | 0.03 | 10--15 | 16--18 | 2--3 |
| TP 316Ti | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 11--14 | 16--18 | 2--3 |
| TP 317 | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 11--14 | 18--20 | 3--4 |
| TP 321 | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 9--13 | 17--20 | |
| TP 321H | 0.04-0.10 | 0.75 | 2 | 0.04 | 0.03 | 9--13 | 17--20 | |
| TP 347 | 0.08 | 0.75 | 2 | 0.04 | 0.03 | 9--13 | 17--20 | |
| TP 347H | 0.04-0.10 | 0.75 | 2 | 0.04 | 0.03 | 9--13 | 17--20 | |
