What is the difference between stainless steel ASTM A403 304 304L 304H?
The stainless steel material ASTM 304 is the most common grade in industry field.In steel piping systems,there are pipes,fittings,flanges and other products are made from ASTM 304 stainless steels.
They are from different material standards,like the ASTM A213,A312,A182 and A403 etc.There are three 304 grades materials in these standards:ASTM A403 WP304,ASTM A403 WP304L,ASTM A403 WP304H,they are looks very familiar,only different from the carbon content in chemical composition.(ASTM A403 WP304H Pipe Fittings)
From followings technical data,we can know the difference between the 3 grades:
| C | Mn | P | S | Si | Cr | Ni | N | |
| 304 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 18.00-20.00 | 8.00-10.50 | 0.1 |
| 304L | 0.03 | 2 | 0.045 | 0.03 | 0.75 | 18.00-20.00 | 8.00-12.00 | 0.10 |
| 304H | 0.04-0.10 | 2 | 0.045 | 0.03 | 0.75 | 18.00-20.00 | 8.00-10.50 |
| T.S（MPa） | Y.S（MPa） | Elongation | Hardness | ||
| % | HB | HR | |||
| 304 | ≥515 | ≥205 | ≥40 | ≥201 | ≥92 |
| 304L | ≥485 | ≥170 | ≥40 | ≥201 | ≥92 |
| 304H | ≥515 | ≥205 | ≥40 | ≥201 | ≥92 |
304L means low carbon,304H means high carbon.Because of the difference of carbon content,the 304H have a better heat and corrosive resistant,and the 304L material has a good welding performance.
This is the most important difference between the three grades.Haihao Group can manufacture the ASTM A403 WP304 pipe fittings,ASTM A403 WP304L pipe fittings and ASTM A403 WP304H pipe fittings in high quality and soon delivery.