Short answer: The defensible verification route combines purchase-document traceability with chemical analysis. XRF can rapidly identify molybdenum-bearing 316 and many alloy families; OES can measure light elements such as carbon more effectively. A magnet, spark or color check is only a screening tool.
This guide is written for stainless steel buyers, sourcing teams, engineers and product manufacturers. The purpose is not to declare one universal winner, but to turn a broad material question into a specification that a mill or service center can quote, process and inspect consistently.
Quick Comparison
| Option | Key point | Typical use or decision |
|---|---|---|
| MTC and heat number | Document and physical traceability | First control for every shipment |
| Handheld XRF | Fast alloy chemistry screening | Useful for separating 304 and 316 |
| OES laboratory test | Broader chemistry including carbon | Useful for L-grade confirmation |
| Magnet | Microstructure screening only | Cannot prove 304 or 316 |
The table is a starting point. Actual performance depends on the governing standard, delivered condition, dimensions, surface finish, fabrication route and service environment. Commercial names should never replace a complete purchase specification.
What Buyers Should Evaluate
- Match heat numbers on material, labels and certificate.
- Calibrate instruments and document the test locations.
- Use an agreed sampling plan for coils or sheet packs.
For production orders, share the end use rather than requesting a grade or finish in isolation. A supplier can then review corrosion exposure, forming severity, welding, visual requirements and packing before material is cut. This early review is usually less expensive than correcting a rejected shipment or unstable production trial.
Common Purchasing Mistakes
- Accepting an unrelated certificate
- Using XRF alone to certify low carbon
- Believing a magnet can separate 304 from all alternatives
These mistakes are avoidable when drawings, approved samples, inspection methods and certificate requirements are agreed before production. For visual products, retain a signed master sample. For functional dimensions, define where and how measurements will be taken.
Recommended RFQ Wording
Require EN 10204 3.1 where appropriate, heat-number marking, no mixed heats without approval, and PMI sampling with acceptance chemistry tied to the named standard.
Also include order quantity, acceptable quantity variation, destination, required delivery date and whether partial shipments are allowed. If a requirement is critical, make it measurable and place it on the purchase order rather than only in an email conversation.
How Still Steel Supports the Project
Still Steel supplies stainless steel coil, strip and sheet and provides slitting, cut-to-length, brushing, polishing and protective-film services. We can compare available mill material with your drawing, prepare trial quantities and preserve heat-number traceability through service-center processing.
Send the grade, dimensions, annual volume and application to vip@still-steel.com, or discuss the requirement on WhatsApp.
Frequently Asked Questions
Can XRF distinguish 304 from 316?
Usually yes because 316 contains molybdenum, but calibration and test procedure still matter.
Can XRF confirm 304L?
Not reliably by carbon content. OES or laboratory chemistry is normally needed for low-carbon verification.
Is a magnet test useful?
It can screen magnetic ferritic or martensitic grades, but cannot conclusively authenticate 304 or 316.
Technical References
Reference documents support general selection and fabrication principles. The final material decision must follow the applicable contract, standard, regulation and engineering review for the specific product.