MTR Versus CoC Versus Test Report
The mill test report comes from your steel supplier and describes the heat: chemistry, mechanical properties, and often the melt and manufacturing location. The CoC comes from you and certifies the lot you shipped. A finished-product test report records your own tests on the lot, such as hardness, tensile or proof load, and coating thickness.
Customers differ on which they need. A distributor may want a simple CoC, an automotive customer may want a full PPAP package, and a defense customer may want melt-origin statements with the MTR. Know which documents each customer's purchase order requires and attach them to the customer record so they are not rediscovered each time.
What a Good Fastener CoC Contains
At minimum: your company name and address, customer name and purchase order number, part number and description, quantity shipped, lot number, specification and revision the lot conforms to (for example an ASTM, SAE or customer drawing revision), material and heat number, finish or coating, date, and an authorized signature or electronic equivalent. Add test result summaries if the PO requires them. Certain customers require statements such as country of melt, RoHS or REACH compliance, or that the product is free of mercury and other restricted materials.
Keep statements truthful and specific; a blanket claim your records cannot support is a liability.
- PO number, part number and revision
- Lot number tied to heat number
- Specification, revision and test summary
- Authorized signature and date
Where Cert Packages Go Wrong
The common failures are certs that reference the wrong revision, heat numbers copied incorrectly from a mill cert, a lot that blended two heats with only one named, plating or heat treat vendor certs missing from the package, and missing signatures. Another is quietly re-keying numbers from a mill cert PDF into a spreadsheet: one transposed digit breaks traceability. Customers and auditors catch these, and a rejected package can hold up payment.
The fix is to generate the CoC from stored lot data, with the mill cert and vendor certs attached automatically, instead of retyping.
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Material Certificate of Conformance Template
Generate a material CoC with purchase order, specification, heat lot, test results and a signed statement of conformance.
Generating Certs From Lot Data
If your ERP stores heat number, lot number, test results and customer requirements, a cert can be assembled as a report at shipment. Many ERPs support custom document templates for this. Where certs are scanned PDFs, extracting heat numbers and values with OCR plus a reviewing person works better than manual retyping.
A private AI assistant can read incoming mill certs, extract heat, chemistry and properties into structured fields, compare them against the specification limits, and flag out-of-spec values for a quality manager. The system drafts, a person approves, and nothing writes back to the ERP without that approval.
When This Is Not Worth Automating
If you ship a handful of lots a week with a single customer and a one-page CoC, a clean Word or Excel template is fine. The payoff comes when you ship many lots per week with different customer cert formats, when your quality person spends hours assembling packages, or when cert errors are generating rejections. Measure the hours spent per week on cert assembly and the number of rejected packages in the last year before deciding.
Frequently asked questions
What is the difference between a CoC and a mill cert?
A mill cert (material test report) comes from the steel producer and documents the heat. A certificate of conformance comes from the manufacturer of the finished part and certifies that the shipped lot meets the specification and purchase order.
Do fasteners need a certificate of conformance?
Not always by law, but many customer purchase orders and quality systems require one, and the Fastener Quality Act and aerospace and automotive specs set expectations for lot records. Check each customer's requirements.
Can AI read mill test reports?
Yes, to extract heat numbers and values into structured fields and compare them with specification limits. A person should review exceptions and approve before the data is used in a cert.
Netray can read your mill certs and lot records on your own infrastructure and draft cert packages for quality review, with exceptions flagged before shipment.