Vertex Alloy
Industrial metal background

254 SMO Stub End (UNS S31254 / EN 1.4547)

Alloy SteelOthers
254smo

Overview

254 SMO stub end is a pipe fitting made from 254 SMO, a high-alloy super-austenitic stainless steel (also known as 6Mo super-austenitic). It is designed for use with lap joint flanges in piping systems requiring exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in severe chloride environments.

Description (English)

254 SMO stub end is a pipe fitting made from 254 SMO, a high-alloy super-austenitic stainless steel (also known as 6Mo super-austenitic). It is designed for use with lap joint flanges in piping systems requiring exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in severe chloride environments.

Size Range

  • 1/2" (DN15) – 24" (DN600)

Grade Specification

SystemValue
🇺🇸 UNSS31254
ASTM / ASMEA182 F44 (forgings), A312 TP31254 (pipe), A403 WP31254 (fittings)
🇪🇺 EN1.4547 (X1CrNiMoCuN20-18-7)
🇪🇺 EN1.4547
🇯🇵 JISSUS31254
🇨🇳 GB015Cr21Ni26Mo5Cu2 (S31254)

Chemical Composition

ElementValue
C≤ 0.020
Si≤ 0.80
Mn≤ 1.00
P≤ 0.030
S≤ 0.010
Cr19.5 – 20.5
Ni17.5 – 18.5
Mo6.0 – 6.5
Cu0.50 – 1.00
N0.18 – 0.22
FeBalance

Mechanical Properties

productCenter.propertyValue
Tensile Strength Rm≥ 650 MPa
Yield Strength Rp0.2≥ 300 MPa
Elongation A (50mm)≥ 35%
Reduction in Area-
Hardness≤ 210 HB
Impact KV2 (room temp)-

Physical Properties

PropertyUnitValue
Densityg/cm³8.00 g/cm³
Melting Point Range°C1,320 – 1,390 °C
Modulus of ElasticityGPa195 GPa
Shear Modulus-74 GPa
Poisson's Ratio-0.30
Thermal Conductivity (20°C)W/m·K14 W/(m·K)
CTE (20–100°C)-16.5 ppm/°C
Specific Heat (20°C)J/kg·K0.50 kJ/(kg·K)
Electrical Resistivity (20°C)μΩ·cm0.85 μΩ·m
Magnetism-Non-magnetic (fully austenitic)

Applications

  • Seawater Systems
  • Oil & Gas / Offshore
  • Chemical Processing
  • Power Generation
  • Desalination
  • Pulp & Paper
  • Pharmaceutical
  • Food / Beverage
  • Marine