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254SMO/6MO

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% of molybdenum and a high level of nitrogen, providing high resistance to pitting and crevice corrosion, combined with high strength, compared with other austenitic stainless steels as 316L, 317L and 904L. These alloys where developed for use in halide containing environments such as brackish water, seawater, hydrochloric acid and sculpture acid. The increased levels of molybdenum combined with chromium and nitrogen provide levels of pitting and crevice corrosion resistance more typically associated with 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) nl
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