254 SMo/6Mo - 1.4547
Wst. 1.4529/1.4547
UNS N08367/S31254
Stock program: 3 – 38 mm OD / 1/8” – 1.1/2” OD
Specification: ASTM A 269/A 213/A 1016, NACE MR0175, PED 97/23 EC / EN 10216-5 / NORSOK M-650 MDS R18
Maximum exposure temperature: 400°C / 848°F
6Mo/254SMO is a super austenitic stainless steel with a minimum of 6% molybdenum and a high level of nitrogen, providing high resistance to pitting and crevice corrosion combined with high strength compared to other austenitic stainless steels like 316L, 317L and 904L. These alloys were developed for use in halide containing environments such as brackish water, seawater, hydrochloric acid and sulphuric acid. The increased levels of molybdenum combined with chromium and nitrogen provide levels of pitting and crevice corrosion resistance more typically associated with the higher alloy 625 (UNS NO6625).
Characteristics
- High resistance to general corrosion
- Excellent resistance to stress corrosion crashing
- Better strength than conventional austenitic stainless steels
- Good weldability
Market applications:
- Offshore, oil & gas
- Chemical processes
- Seawater systems
- Control and instrumentation
- Desalination plant equipment
- Pulp and paper processing
Technical details
| Technical composition (%) | Fe | Cr | Ni | Mo | Mn | Cu | Si | P | N | C | S | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 254SMO | min | Bal. | 19.5 | 17.5 | 6.0 | - | 0.5 | - | - | 0.18 | - | - |
| max | - | 20.5 | 18.5 | 6.5 | 1.00 | 1.0 | 0.80 | 0.03 | 0.25 | 0.030 | 0.010 | |
| 6MO | min | Bal. | 20.0 | 23.5 | 6.0 | - | - | - | - | 0.18 | - | - |
| max | - | 22.0 | 25.5 | 7.0 | - | 0.75 | 1.00 | 0.04 | 0.25 | 0.040 | 0.030 |
| Mechanical properties | 254SMO | 6MO |
|---|---|---|
| Tensile strenght (mpa, min) | 650 - 850 | 675 - 875 |
| Yield strength (0.2% offset mpa, min) | 300 - 340 | 310 - 350 |
| Elongation (%, min) | 35 | 30 |
| Density / weight (g / cm3 / kg) | 8.05 | 8.05 |