ER347 MIG / GMAW filler metal is a common starting point for austenitic stainless work where the base metal is 321 or 347 stabilized stainless. The key point is simple: do not treat the filler label as a final approval. Confirm the WPS, code requirements, base metal grade, service conditions, and manufacturer data sheet before ordering wire or striking an arc.
On the Weld Support Parts filler metal page, ER347 is presented as a selection starting point, not a guarantee of procedure acceptance. That matters on stainless jobs because base metal mix-ups, wrong service conditions, and unverified heat input targets can create repair delays or rejection during inspection.
Key Takeaways
- ER347 is a niobium-stabilized stainless filler metal used for 321 and 347 stainless applications.
- Use the filler metal page to narrow the search, then verify against the WPS and the manufacturer data sheet.
- Do not assume ER347 is interchangeable with other stainless wires such as ER308L. Verify the applicable procedure first.
- Wire diameter options listed on the source page include .030 in, .035 in, and .045 in. Confirm the exact size you need on the purchase page and against the wire feed setup. Unknown (Verify) if a specific diameter is acceptable for your procedure.
- For stainless service, verify corrosion exposure, temperature range, and any code or customer restrictions before use.
Selection and Support Checks
If you are supporting a job package or buying for a maintenance crew, use this sequence.
- Check the WPS. Confirm the process is MIG / GMAW and the filler classification is allowed. If the WPS is not available, stop and verify with welding engineering or the responsible supervisor.
- Inspect the base metal stamp or mill cert. Verify whether the part is 321 or 347 stainless, or another grade. Unknown (Verify) if the material ID is unclear.
- Verify service conditions. Stainless filler selection can depend on heat exposure, corrosion environment, and post-weld requirements. Do not assume the wire is correct for all service.
- Match wire size to feed equipment. Check drive rolls, liner condition, gun setup, and contact tip size. A poor feed setup can look like a filler problem when it is actually a delivery problem.
- Confirm shielding gas and parameters. Use the gas and settings called out by the WPS or the manufacturer data sheet. Unknown (Verify) if your shop standard has not been approved for this job.
Troubleshooting and Support
When ER347 wire is being considered for a job and the setup is not performing as expected, work through the problem before changing materials.
Issue: Wire feeding is erratic
- Check the liner for wear or contamination.
- Inspect drive roll tension and groove type.
- Verify the contact tip is sized for the wire diameter.
- Confirm the spool is not damaged or contaminated.
If feed problems continue, review the torch lead length and any tight bends that may be increasing drag. Unknown (Verify) if the issue is electrical, mechanical, or a combination until the feed path is inspected.
Issue: Bead appearance or wetting is inconsistent
- Verify the shielding gas and flow rate against the WPS.
- Check for drafts, nozzle contamination, or spatter buildup.
- Inspect work lead placement and connection quality.
- Review travel speed and stickout against the approved procedure.
Do not change filler metal first. Verify process settings and gas coverage before replacing wire.
Issue: Material designation is uncertain
- Inspect tags, stamps, drawings, and mill paperwork.
- Check whether the job is 321, 347, or another stainless grade.
- Verify whether the customer or code basis allows ER347.
- If uncertain, hold the job and request written clarification.
Unknown (Verify) is the correct status whenever the base metal grade or service requirement cannot be proven from the paperwork and the part itself.
Filler Metal Finder Notes
The Weld Support Parts filler metal finder page is useful as a selection starting point. Use it to narrow the search by process and classification, then validate the result against the WPS and the manufacturer data sheet. It is not a procedure approval tool.
The ER347 page at ER347 MIG / GMAW Filler Metal gives the basic classification and application note for 321 and 347 stabilized stainless. Treat that page as a reference point for procurement and job support. Do not assume it covers every code, every position, or every service condition.
What Buyers and Supervisors Should Verify Before Ordering
- Classification on the WPS: ER347, or another approved filler, Unknown (Verify) if not documented.
- Base metal grade: 321 or 347 stainless, or another stainless grade if the drawing calls for it.
- Wire diameter: .030 in, .035 in, .045 in, or another size if required by the procedure.
- Shielding gas and transfer mode: verify from the approved welding document.
- Packaging and storage needs: confirm dry storage and handling requirements with the supplier data sheet.
For maintenance buyers, the practical risk is simple: a stainless wire can be physically in stock and still be the wrong choice for the job. Confirm the paperwork first, then buy to match the verified requirement.
Safety Notes
- Follow the site hot work permit process before welding.
- Use the approved PPE for stainless welding, including eye, face, hand, and body protection.
- Provide adequate ventilation and fume control.
- Do not weld on unidentified material until it is verified.
- Keep wire, gun, and gas equipment in safe condition before use.
Stainless welding can generate fumes and heat exposure risks. Review the manufacturer safety data and the shop safety rules before use.
FAQ
Is ER347 the same as ER308L?
No. They are different filler classifications. Do not substitute without checking the WPS and the approved procedure. Unknown (Verify) if a substitution is allowed.
Can ER347 be used on any stainless steel part?
No. The source material identifies it for 321 and 347 stabilized stainless applications. Verify the base metal grade and service condition before use.
Should I use the filler metal page as proof of approval?
No. The filler metal page is a starting point for selection. Final approval comes from the WPS, customer requirements, code basis, and manufacturer data.
What wire sizes are listed on the source page?
The source keywords include .030 in, .035 in, and .045 in. Verify the exact size against the job requirements and the product listing before ordering.
Sources Checked
- Weld Support Parts filler metal finder: https://www.weldsupportparts.com/filler-metal-finder.html
- Weld Support Parts ER347 MIG / GMAW filler metal page: https://www.weldsupportparts.com/filler-metal-mig-er347.html
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