ER309LMo

Class: ER309LMo
AWS: A5.9

Conforms to Certification: AWS A5.9 | ASME SFA A5.9

Weld Process Used for Tig: (GTAW)

AWS Chemical Composition Requirements
C = 0.03 max
Cr = 23.0 – 25.0
Ni = 12.0 – 14.0
Mo = 2.0 – 3.0
Mn = 1.0 – 2.5
Si = 0.30 – 0.65
P = 0.03 max
S = 0.03 max
Cu = 0.75 max

Available Sizes
.030 x 36
.035 x 36
.045 x 36
1/16 x 36
3/32 x 36
1/8 x 36
3/16 x 36
5/32 x 36

Application
This classification has a low carbon content of 0.03% max. ER309LMO is usually needed for the first layer to achieve low carbon contents in other layers with ER316L or ER317L.

Deposited Chemical Composition % (Typical)
C = 0.02 Mo = 2.40 P = 0.012
Cr = 23.75 Mn = 1.75 S = 0.010
Ni = 13.10 Si = 0.40
Mechanical Properties (R.T.) 
Yield Strength 58,000 psi
Tensile Strength 85,000 psi
Elongation 36%
Reduction of Area 55%

Deposited All Weld Metal Properties
Data is typical for ER309LMo weld metal deposited by Tig using 100% Argon as the shielding gas.

Recommended Welding Parameters

GTAW “Tig Process”
Wire Diameter Amps DCSP Volts Shielding Gas
.035 60-90 12-15 Argon 100%
.045 80-110 13-16 Argon 100%
1/16 90-130 14-16 Argon 100%
3/32 120-175 15-20 Argon 100%

Note: Parameters for tig welding are dependent upon plate thickness and welding position.
Other shielding Gases may be used for Tig welding. Shielding gases are chosen taking Quality, Cost, and Operability into consideration.