SS 904L is superior grade then other stainless steel grades!
by Dinesh
Posted on October 13, 2017 at 1:00 PM
904L is a non-stabilised low carbon high alloy austenitic stainless steel. Alloy 904L performs better than other austenitic stainless steels due to the higher alloying of nickel and molybdenum. 904L has a greater resistance to precipitation of ferrite and sigma phases on cooling and welding than other stainless steels containing molybdenum such as SMO 254, 253 MA, DUPLEX 2205 and SS 310L.
Chemical Composition of Stainless Steel Grades:
| SS 904L | SMO 254 | 253 MA | DUPLEX 2205 | SS 310L | |
| C | <0.020% | <0.02% | 0.5%-0.10% | <0.03% | <0.25% |
| Cr | 19.0%-23.0% | 19.5%-20.5% | 20%-22% | 21%-23% | 24.00-26.00 |
| Cu | 1.0%-2.0% | 0.5-1.0 | - | - | - |
| Mn | <2% | <1 | <0.8% | <2.00% | <2.00% |
| Mo | 4.0%-5.0% | 6.0%-6.5% | - | 2.50%-3.50% | - |
| Ni | 23.0%-28.0% | 17.5%-18.5% | 10%-12% | 0.8%-020% | 19.00-22.00 |
| P | <0.045% | <0.03% | <0.04% | <0.03% | <0.045% |
| S | <0.0350% | <1.01% | <0.03% | <0.02% | <0.030% |
| Si | <1% | <0.8% | 1.40%-2.0% | <1.00% | <1.50% |
| Fe | - | 55.69% | Balance | 0.03% | - |
| N | - | 0.18%-0.22% | 0.14%-0.20% | 2% | - |
| Ce | - | - | 0.03%-0.08% | - | - |
Mechanical properties of Stainless Steel Grades:
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
| Rockwell B (HR B) | Brinell (HB) | ||||
| SS 904L | 490 | 220 | 35 | 70-90 typical | - |
| SS 310L | 515 | 205 | 40 | 95 | 217 |
| SMO 254 | 680 | 254 | 50 | 87 | 210 |
| 253 MA | 600 | 310 | 40 | 95 | 217 |
| DUPLEX 2205 | 621 | 448 | 25 | 31 | 293 |
Characteristics of Stainless Steel 904L:
904L stainless steels possess excellent resistance to warm seawater and also from chloride attack. The above the normal resistance in grade 904L against stress corrosion cracking is due to the presence of high amounts of nickel. The alloy is less resistant to nitric acid than grades 304L and 310L.
Grade 904L stainless steels also have excellent weldability which can be performed using all conventional methods. This steel does not require pre-heat and post-weld heat treatments.
The steel structure collapses only at a temperature above 400 C.
Hot work should proceed after uniform heating to 2000-2200 F. Doe not work the material at less than 1800 F. Full annealing should follow any hot work to reattain maximum ductility and corrosion resistance.
Although higher forces are required, 904L will respond in a similar fashion to other austenitic stainless steels like 304, 316 or 317. Most common operations can be successfully performed.
1920-1990 F (1050-1090 C), rapid cooling.
This alloy does not respond to heat treatment. It may only be hardened by cold reduction.