ER318 Welding Wire
ER318 welding wire is a niobium-stabilized, molybdenum-bearing austenitic stainless steel filler metal classified under AWS A5.9. It contains chromium, nickel, molybdenum, and niobium, with the niobium addition helping reduce chromium carbide precipitation in the weld metal. Metracore manufactures and supplies ER318 welding wire as COREWELD 318 for compatible stainless steel welding applications in chemical processing, pharmaceutical equipment, food-processing equipment, and related process industries. The product is available in MIG wire and TIG rod forms, subject to the specified product size and certification. Filler metal selection depends on the base stainless steel grade, service conditions, welding process, and approved welding procedure.
ER318 Welding Wire and ER318 Tig & MIG Wire Supplier
Niobium stabilisation defines ER318: AWS A5.9 designates this grade as a molybdenum-bearing austenitic stainless filler metal built around that addition. Niobium is the element that sets it apart: it combines preferentially with carbon during welding, which limits the chromium carbide precipitation that causes intergranular corrosion in unstabilised grades. Chromium, nickel, and molybdenum contribute to the corrosion resistance of the weld deposit, with performance depending on the alloy, environment, and welding procedure. Buyers use it for welding compatible stainless steel grades where that corrosion resistance needs to survive the heat of welding itself. Filler metal selection depends on the stainless steel grade, service conditions, and the approved welding procedure.
Technical Specifications of COREWELD 318
COREWELD 318 ER318 welding wire carries verified AWS A5.9 classification, summarised in the table below.
| Specification | Details |
| Brand | COREWELD 318 |
| Product Name | ER318 Welding Wire |
| AWS Classification | ER318 |
| Material Type | Austenitic Stainless Steel Filler Metal |
| Stabilizing Element | Niobium (Nb/Cb) typically around 0.6% to stabilize against intergranular corrosion/weld decay |
| Welding Processes | GMAW (MIG), GTAW (TIG), and SAW (Submerged Arc) |
| Applicable Standard | Certified to SFA-5.9 / SFA-5.9M (AWS A5.9 / ASME SFA-5.9) |
| Available Wire Diameters | Typically offered in: • GMAW/GTAW: 0.035″, 0.045″, 1/16″, 3/32″, 1/8″, 5/32″ • SAW: 2.50 mm, 3.20 mm, 4.00 mm |
| Rod Lengths | Standard TIG cut lengths are 36″ (914 mm), or customized based on request. |
| Packaging | MIG/TIG: Spools, carrier coils, or standard tubes. SAW: 25 Kg wire in metallic rings packed in corrugated cardboard boxes. |
| Base Material Compatibility | Primarily used for welding titanium or niobium (columbium) stabilized chromium-nickel-molybdenum steels such as AISI 316, 316L, 317, and 318 |
Chemical Composition of ER318 Welding Wire
| Element | Composition |
| Carbon (C) | 0.08% max (typical AWS A5.9 range) |
| Chromium (Cr) | 18.0-20.0% (typical AWS A5.9 range) |
| Nickel (Ni) | 11.0-14.0% (typical AWS A5.9 range) |
| Molybdenum (Mo) | 2.0-3.0% (typical AWS A5.9 range) |
| Niobium (Nb) | 8xC min to 1.00% max (typical stabilisation range) |
| Manganese (Mn) | 1.0-2.5% (typical AWS A5.9 range) |
| Silicon (Si) | 0.30-0.65% (typical AWS A5.9 range) |
| Iron (Fe) | Balance, subject to specification |
Mechanical Properties of ER318 Weld Metal
| Property | Value |
| Tensile Strength | 610 – 650 MPa (Approx. 88,500 – 94,200 psi) |
| Yield Strength | 154 MPa minimum (Standard material) |
| Elongation | 27% to 35% (Minimum 27% with SAW flux; typical up to 35% on standard test) |
| Impact Properties | Charpy V-Notch (Notch impact test) is applicable (tested per Kerbschlagbiegeversuch); tough performance at cryogenic temperatures is documented |
Equivalent Grades of ER318 Welding Wire
| Standard | Designation |
| AWS A5.9 | ER318 |
| ASME SFA-5.9 | ER318 |
| EN ISO 14343 | S 19 12 3 Nb, where applicable |
Applications of ER318 Welding Wire
The following are various industrial applications. ER318 Welding Wire:
- Chemical processing vessels and piping
- Pharmaceutical equipment requiring corrosion-resistant welded joints
- Food-processing equipment where intergranular corrosion resistance matters
- Pressure vessel fabrication in compatible stainless grades
- Pipe spool welding for process industries
- Repair welding of niobium-stabilised stainless components
Manufacturing Process of ER318 Welding Wire
Niobium is introduced during alloying, ahead of the hot working and drawing stages shared with other austenitic wires.
- Alloying with chromium, nickel, molybdenum, and a controlled niobium addition
- Hot rolling of the billet into intermediate rod
- Cold drawing through successive dies to finished wire or rod diameter
- Straightening, cutting, and spooling or cut-length packing
- Chemistry verification to confirm niobium stabilisation against AWS A5.9
Key Benefits of COREWELD 318 Filler Metal
The use of niobium stabilisation and molybdenum addition makes COREWELD 318 filler metal resistant to intergranular corrosion and also pitting in process equipment.
- Niobium stabilisation suppresses chromium carbide precipitation in heat-affected zones by carbon trapping
- Specific resistance against localised pitting and crevice corrosion in chloride media with molybdenum addition
- Toughness and good mechanical strength are present in the austenitic matrix in harsh chemical process environments
- Controlled ferrite levels to reduce susceptibility to micro-cracking in multi-pass welding on thick plate sections
- Smooth arc characteristics for good radiography-grade welds and simple detachability of the slag in all places
Why Choose COREWELD 318 Welding Wire?
COREWELD 318 carries verified AWS A5.9 classification, with wire diameters, packaging, and technical support confirmed on the official datasheet rather than left to assumption. Buyers evaluating this filler metal for a chemical, pharmaceutical, or food-processing application should review the datasheet for technical details before selecting it. Documentation for the niobium-stabilised classification is available alongside the standard product paperwork. No claims are made regarding certifications, quality guarantees, or manufacturing capabilities beyond what is documented for this specific product.
ER318 Welding Wire Supply and Technical Support
Enquiries cover confirmed wire diameters, TIG rod sizes, packaging, and bulk requirements once the base stainless grade is known. Share the base stainless steel grade, welding process, and required dimensions when requesting product information. Stock availability, delivery timelines, and export coverage are mentioned only once verified.
Products
FAQ's
What is ER318 welding wire used for?
It welds compatible stainless grades in chemical, pharmaceutical, and food-processing equipment needing corrosion-resistant joints.
What is the difference between ER318 TIG wire and MIG welding wire?
ER318 TIG wire is supplied as a cut-length rod for manual TIG welding, while ER318 MIG wire is supplied in continuous lengths for feeding through a GMAW gun. The filler metal classification and chemistry are based on the same ER318 designation, while the product form and diameter depend on the welding process.
Which stainless steel grades are compatible with ER318 filler metal?
Compatible molybdenum-bearing austenitic grades, subject to confirmation against the welding procedure specification.
What is the role of niobium in ER318 welding wire?
Niobium combines with carbon during welding, limiting the chromium carbide precipitation that causes intergranular corrosion.
What sizes are available for COREWELD 318?
Confirm wire diameters, rod sizes, and packaging from the current datasheet.
Which standard applies to ER318 welding wire?
AWS A5.9 / ASME SFA-5.9, subject to certification on the product datasheet.