ER318 is a molybdenum-alloyed and niobium-stabilized stainless steel welding rod classified under AWS A5.9-2022. It is primarily selected for welding compatible stabilized Cr-Ni-Mo stainless steels when the welding procedure requires a stabilized filler metal.
What Makes ER318 Different?
ER318 combines chromium, nickel, molybdenum, and niobium in one filler-metal composition. Its principal composition ranges include:
- 18.0–20.0% chromium
- 11.0–14.0% nickel
- 2.0–3.0% molybdenum
- Controlled niobium related to carbon content
- Maximum 0.08% carbon
Chromium and nickel support the stainless-steel weld structure, while molybdenum contributes to performance in applications where a Mo-alloyed weld deposit is specified. Niobium serves as a stabilizing element.
Typical ER318 Applications
ER318 may be considered for:
- Compatible niobium-stabilized stainless steels
- Cr-Ni-Mo stainless-steel components
- Chemical-processing equipment
- Stainless piping and vessels
- Heat-exposed stainless-steel assemblies
- Maintenance of matching stabilized alloys
The exact application must be confirmed against the base-metal grade, service environment, construction code, and approved welding procedure.
Mechanical Performance
ER318 weld metal has a minimum tensile-strength requirement of 550 MPa and a minimum elongation requirement of 25%. Typical results may reach 592 MPa tensile strength and 42% elongation, indicating a useful combination of strength and ductility.
Selecting ER318 Correctly
ER318 should not be selected solely because an application involves stainless steel. Before ordering, buyers should provide the base-metal grade, required standard, welding process, service temperature, corrosive medium, diameter, and quantity.
Dayang Welding supplies ER318 stainless steel welding rods for global industrial applications and supports customers with product selection and technical documentation.
