Datasheet updated

2024-01-11 10:32
(supersedes all previous editions)

Alleima® 8RE18 is an austenitic chromium-nickel steel for high-temperature applications.


  • ASTM: TP309S, TP309H
  • UNS: S30908/S30909
  • EN Number: 1.4833

Chemical composition (nominal)

Chemical composition (nominal) %
C Si Mn P S Cr Ni
0.07 0.5 1.7 ≤0.035 ≤0.015 22.5 14

Mechanical properties

At 20oC (68oF)

Proof strength Tensile strength Elong.
Rp0.21) Rm A2)
MPa ksi MPa ksi %
≥205 ≥30 >515 >75 ≥35

1 MPa = N/mm2
1) Rp0.2 0 corresponds to 0.2% offset yield strength.
2) Based on L0 = 5.65 √S0 where L0 is the original gauge length and S0 the original cross-section area.


The weldability of Alleima® 8RE18 is good. Welding must be carried out without preheating and subsequent heat treatment is normally not required. Suitable methods of fusion welding are manual metal-arc welding (MMA/SMAW) and gas-shielded arc welding, with the TIG/GTAW method as first choice.

For Alleima® 8RE18, heat input of <2.0 kJ/mm and interpass temperature of <150°C (300°F) are recommended.

Recommended filler metals

TIG/GTAW or MIG/GMAW welding

ISO 14343 S 22 12 H / AWS A5.9 ER309Si (e.g. Exaton 24.13.Si)

MMA/SMAW welding

ISO 3581 E 22 12 R / AWS A5.4 E309-17

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.