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UNS S31254 Stainless Steel Pipe belongs to the super austenitic stainless steel pipe, which is widely used in many fields due to its excellent corrosion resistance, high strength and good processing performance. Compared with ordinary stainless steel pipe, its chemical composition has been carefully blended, containing a higher proportion of chromium (Cr), nickel (Ni), molybdenum (Mo), nitrogen (N) and other alloying elements, so as to have a more excellent comprehensive performance.
UNS S31254, commonly known as 254 SMO or F44, is a high-performance super austenitic stainless steel developed for extreme environments with high chloride concentrations, such as seawater or corrosive chemical processing, and designed to provide superior performance in extremely harsh corrosive environments. Its uniqueness lies in its high content of chromium, nickel, molybdenum and nitrogen, which work in synergy to give it excellent corrosion resistance and mechanical strength. It is particularly good at resisting pitting, crevice corrosion and stress corrosion cracking. Contact us
· Excellent Pitting Resistance
PREN (Pitting Resistance Equivalent Number) > 42, much higher than 316L or Duplex 2205.
· Superior Crevice Corrosion Resistance
Ideal for stagnant chloride-rich conditions.
· High Strength
Yield strength nearly twice that of 300-series stainless steels.
· Good Weldability
Suitable for TIG, MIG, and manual welding using matching filler metals.
· Non-magnetic
Due to its fully austenitic structure.
Specifications | ASTM A 312 ASME SA 312, ASTM A 213 ASME SA 213, ASTM A269 ASME SA 269 |
Dimensions | ASTM, ASME and API |
Size | 3/4″ – 12″ |
Specialized in | Large Diameter Size |
Thickness | 20 Swg., 18 Swg., 16 Swg., 14 Swg., 12 Swg., 10 Swg., & Sch. 10, Sch. 40, Sch. 80 etc. |
Type | Seamless / ERW / Welded / Fabricated |
End | Plain End, Beveled End, Treaded |
CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu |
SMO 254 | MIN | 17.5 | 19.5 | 6 | 0.18 | 0.5 | |||||
MAX | 0.02 | 1 | 0.03 | 0.01 | 0.8 | 18.5 | 20.5 | 6.5 | 0.25 | 1 |
Density | Melting Point | Yield Strength (0.2%Offset) | Tensile Strength | Elongation |
8.0 g/cm3 | 1320-1390 ℃ | 300 | 650 | 35% |
STANDARD | UNS | WERKSTOFF NR. | AFNOR | EN | JIS | SIS | GOST |
SMO 254 | S31254 | 1.4547 | Z1 CNDU 20.18.06Az | X1CrNiMoCuN20-18-7 | – | 2378 | – |
Pitting resistance：With its high chromium, molybdenum and nitrogen content, UNS S31254 stainless steel pipe has excellent pitting resistance. The pitting corrosion equivalent (PREN) value is usually ≥43, which is much higher than that of common stainless steel (e.g. PREN≈24 for 316L).
Crevice corrosion resistance: in the crevice environment, such as pipe connections, gaskets and pipe contact, etc., due to the stagnant flow of the medium and concentration differences, crevice corrosion is likely to occur.
Stress Corrosion Cracking Resistance: The high nickel, chromium and molybdenum content makes it less sensitive to stress corrosion cracking (SCC) in high temperature chlorinated environments. In the complex stress and corrosive media together, UNS S31254 stainless steel pipe can effectively avoid the occurrence of stress corrosion cracking, to ensure the safe operation of pipeline systems in poor working conditions.
Uniform corrosion resistance: In acidic solutions and some oxidizing halide solutions, UNS S31254 stainless steel pipe shows good uniform corrosion resistance, and its corrosion resistance can be comparable with the strongest corrosion resistance of nickel-based alloys and titanium alloys, and it can maintain stable performance in these harsh corrosive environments.
Welding
Welding of stainless steel grade 254 SMO™ requires filler material without which it results in poor strength properties. Filler metals such as AWS A5.14 ERNiCrMo-3, and alloy 625 are recommended. Electrodes used in the process, have to match with AWS A5.11 ENiCrMo-12.
Annealing
Annealing of this material should be performed at 1149-1204°C (2100-2200°F), which should be followed by a water quench.
Hot Working
Forging, upsetting and other operations relating to this material can be performed at 982 - 1149°C (1800 - 2100°F). It is recommended that temperatures do not exceed this range as it would result in scaling and reduction in the workability of the material. To re-attain maximum corrosion resistant properties, it is advisable to perform post-process annealing.
Cold Working
Cold working can be carried out using all the traditional methods; however the process would be tough due to its high work hardening rate. The result will provide the material with increased strength and toughness.
Hardening
Stainless steel grade 254 SMO™ does not respond to heat treatment. Hardening is possible only through cold reduction.
Nominal Size | OD | Sch5s | Sch10s | Sch40s | Sch80s | |||||
DN | NPS | 0 | T | kg/m | T | kg/m | T | kg/m | T | kg/m |
6 | 1/8 | 10.3 | 1.24 | 0.28 | 1.73 | 0.37 | 2.41 | 0.47 | ||
8 | 1/4 | 13.7 | 1.65 | 0.49 | 2.24 | 0.63 | 3.02 | 0.8 | ||
10 | 3/8 | 17.1 | 1.65 | 0.63 | 2.31 | 0.84 | 3.2 | 1.1 | ||
15 | 1/2 | 21.3 | 1.65 | 0.82 | 2.11 | 1 | 2.77 | 1.27 | 3.73 | 1.62 |
20 | 3/4 | 26.7 | 1.65 | 1.04 | 2.11 | 1.28 | 2.87 | 1.69 | 3.91 | 2.2 |
25 | 1 | 33.4 | 1.65 | 1.33 | 2.77 | 2.09 | 3.38 | 2.5 | 4.55 | 3.24 |
32 | 1 1/4 | 42.2 | 1.65 | 1.68 | 2.77 | 2.7 | 3.56 | 3.39 | 4.85 | 4.47 |
40 | 1 1/2 | 48.3 | 1.65 | 1.95 | 2.77 | 3.11 | 3.68 | 4.05 | 5.08 | 5.41 |
50 | 2 | 60.3 | 1.65 | 2.44 | 2.77 | 3.93 | 3.91 | 5.44 | 5.54 | 7.48 |
65 | 2 1/2 | 73.0 | 2.11 | 3.77 | 3.05 | 5.26 | 5.16 | 8.63 | 7.01 | 11.41 |
80 | 3 | 88.9 | 2.11 | 4.6 | 3.05 | 6.45 | 5.49 | 11.29 | 7.62 | 15.27 |
90 | 31/2 | 101.6 | 2.11 | 5.29 | 3.05 | 7.4 | 5.74 | 13.57 | 8.08 | 18.63 |
100 | 4 | 114.3 | 2.11 | 5.96 | 3.05 | 8.36 | 6.02 | 16.07 | 8.56 | 22.32 |
125 | 5 | 141.3 | 2.77 | 9.67 | 3.4 | 11.57 | 6.55 | 21.77 | 9.53 | 30.97 |
150 | 6 | 168.3 | 2.77 | 11.55 | 3.4 | 13.48 | 7.11 | 28.26 | 10.97 | 42.56 |
200 | 8 | 219.1 | 2.77 | 15.09 | 3.76 | 19.96 | 8.18 | 42.55 | 12.7 | 64.64 |
250 | 10 | 273.1 | 3.4 | 23.08 | 4.19 | 27.78 | 9.27 | 60.31 | 12.7 | 96.01 |
300 | 12 | 323.9 | 3.96 | 31.89 | 4.57 | 36 | 9.53 | 73.88 | 12.7 | 132.08 |
350 | 14 | 355.6 | 3.96 | 35.06 | 4.78 | 41.3 | ||||
400 | 16 | 406.4 | 4.19 | 42.41 | 4.78 | 47.29 | ||||
450 | 18 | 457.2 | 4.19 | 47.77 | 4.78 | 53.26 | ||||
UNS S31254 provides significantly improved resistance to pitting and crevice corrosion in chloride environments compared to common austenitic stainless steels such as 304L and 316L. Compared to duplex stainless steels (e.g., 2205), S31254 performs better in some areas and has superior corrosion resistance in specific high chloride and low pH environments. Compared to super duplex stainless steels (e.g. S32750/S32760), S31254 has comparable resistance to pitting corrosion but relatively low yield strength.
Offshore and marine systems
Desalination plants and water treatment facilities
Chemical and petrochemical industries
Pulp and paper processing equipment
Heat exchangers, condensers, and pressure vessels
-Pipe and Tube (EN 10216-5, ASTM A213, ASTM A249, A312, A790,)
-Forged Fitting and Flange (ASTM A182 , ASTM A105,ASTM B564 )
-Butt Weld Fittings (ASTM A234, ASTM A403,ASTM A815)
-Round bar , Billet (ASTM A276, ASTM A479)
- Plate, Sheet, Strip(ASTM A240, EN 10028-7, A480)
-Bolting, Nuts（ASTM A193, A194, A320）
