ER318 is formulated as a Cr-Ni-Mo stainless steel filler metal with niobium stabilization. These alloying elements make it relevant to corrosion-resistant fabrication, but suitability must be evaluated for each specific environment.
Why Is ER318 Considered?
ER318 contains:
- 18.0–20.0% chromium
- 11.0–14.0% nickel
- 2.0–3.0% molybdenum
- Controlled niobium stabilization
Chromium supports the passive surface associated with stainless steel. Molybdenum is included where a Mo-bearing stainless deposit is specified, while niobium stabilizes the weld-metal chemistry in relation to carbon.
What Applications May Use ER318?
Subject to engineering confirmation, ER318 may be considered for:
- Chemical-processing stainless steel equipment
- Matching stabilized Cr-Ni-Mo stainless piping
- Fabrications exposed to suitable corrosive media
- Stainless components experiencing thermal cycles
- Welds requiring an AWS A5.9 stabilized filler
- Repair of compatible stainless steel grades
What Must Be Confirmed First?
Before selecting ER318, engineers should identify:
- Base-metal grade and condition
- Chemical medium and concentration
- Chloride exposure
- Operating and cleaning temperatures
- Design and construction standard
- Welding process and shielding gas
- Heat input and interpass limits
- Post-weld cleaning or passivation
- Required inspection and acceptance criteria
Is ER318 Universally Corrosion-Proof?
No welding consumable is universally corrosion-proof. A correctly classified wire may still produce an unsuitable joint if the base material, heat input, dilution, shielding, or surface treatment is incorrect.
The most reliable approach is to select ER318 through an approved welding procedure and validate the completed joint against the real service conditions.
Dayang Welding supplies ER318 as part of its stainless steel welding consumables range and can coordinate product specifications with the customer's technical requirements.
