How to Verify Mill Test Certificates (MTCs) for Steel Export Orders

A buyer-side checklist for linking the purchase order, physical steel, laboratory results and shipment documents.A buyer-side checklist for linking the purchase order, physical steel, laboratory results and shipment documents.

What an MTC Is - and What It Is Not

In global steel trade, buyers often refer to a Mill Test Certificate as an MTC, material certificate, mill certificate or inspection certificate. The exact terminology can vary by market and contract. The important point is that the purchase order must state what document is required, who must issue or validate it, and what tests and traceability it must cover. ISO 10474:2013 defines types of inspection documents supplied to a purchaser for steel products in accordance with order requirements.

An MTC is not a substitute for a correct specification. It cannot resolve an order that does not define the steel grade, thickness, governing standard, property requirements, document type or acceptance conditions. It is also not, by itself, proof that every cut part in a shipment remains traceable after processing. That link must be maintained by plate marking, cut-part identification, production controls and shipment records.

Write the Certificate Requirement Into the RFQ Before You Compare Prices

The most effective time to control MTC quality is before the supplier quotes. A late request for "full certificates" can lead to uncertainty over scope, added testing costs, delay or documents that do not match the customer's intended acceptance basis. The RFQ should state the exact material standard and revision, the document class required by the contract, the required test items, the traceability method, and whether third-party witnessing or independent testing is required.

• State the steel grade, standard and latest accepted revision. Avoid generic descriptions such as "wear plate 500 HBW."
• State the ordered dimensions, tolerances, quantities, delivery condition and any processing to be performed after supply.
• State the inspection-document requirement. Where the contract requires EN 10204 Type 3.1 or 3.2, write it explicitly and define the required issuing / witnessing party.
• Define the tests that must be reported: chemistry, tensile properties, hardness, impact properties, ultrasonic testing or other tests only where project requirements justify them.
• Require heat-number traceability from incoming plate through cutting, packing and shipment, especially for fabricated or processed orders.
• Define who pays for retesting, what happens if a result is nonconforming and whether replacement material requires repeat inspection.

The Seven-Point MTC Verification Checklist

1. Confirm the issuer and document identity

Check the mill / manufacturer name, document number, date, product identity and any stated inspection basis. A certificate issued by a trading company may be useful commercially, but it should not be confused with the original mill document unless the contract explicitly allows it.

2. Match the purchase order

Compare grade, standard, thickness, width, length, quantity, delivery condition and ordered product form. A correct certificate for the wrong thickness or standard is not acceptance evidence for your order.

3. Match the heat number to physical material

Verify that the heat number or approved traceability mark on the plate, bundle, tag or label matches the certificate. For cut parts, check the plate-to-part mapping and the packing / mark list.

4. Review chemical composition

Read the reported elements against the applicable specification and the project's fabrication needs. For quenched-and-tempered wear plate, chemistry and carbon-equivalent controls can affect welding and heat-affected-zone risk.

5. Review mechanical and hardness results

Confirm the test result, unit, test standard, specimen direction where relevant and acceptance range. Do not treat "typical" brochure values as certificate results.

6. Check test conditions and scope

Look for thickness range, test location, heat / lot relationship and any stated deviations. A result is meaningful only when it applies to the material actually supplied.

7. Reconcile quantity and shipment traceability

A certificate should logically support the quantity it is being used to certify. Reconcile heat-level tonnage, plate numbers, cut-part mapping and packing-list quantities. Any mismatch should be explained in writing before release.

How to Verify an MTC for NM400 or NM500 Wear Plate

Wear-resistant plate introduces one additional discipline: do not rely on grade name alone. The buyer should confirm the stated hardness range for the supplied thickness, how the hardness was tested, whether the test result is tied to the supplied heat or plate, and what chemical / mechanical values are actually reported. GB/T 24186-2022 is a current Chinese national standard for high-strength abrasion-resistant plate, sheet and strip for construction machinery; it is a useful reference point where it is the contract standard, but the order must still state its own acceptance details.

Red Flags That Need Clarification Before Shipment

• The certificate does not name the mill or manufacturing source, or the identity is inconsistent across pages.
• The grade, standard, thickness or dimensions do not match the purchase order.
• No heat number, lot number or controlled traceability reference is shown.
• The certificate lists results but not test method, unit, acceptance basis or thickness relationship.
• One document appears to be used for a quantity that exceeds the amount it plausibly supports, without a clear lot explanation.
• Physical marking, cutting records, packing marks and MTC heat number do not reconcile.
• The document is revised after inspection without an explanation of what changed and why.
• A supplier offers only marketing data or a general catalogue when the PO requires heat-specific evidence.

When Document Review Is Not Enough

For routine, low-risk orders, document review and controlled traceability may be sufficient. For high-value wear parts, critical infrastructure, tightly controlled welding work or projects with significant replacement cost, buyers may add third-party inspection, witnessed sampling, independent chemical analysis, hardness verification, dimensional checks or ultrasonic testing. The test plan should be tied to the actual risk. More testing is not automatically better- tests that don't address the actual failure mode add cost without reducing risk.

Where inspection is used, arrange the scope before production or cutting begins. The inspector needs access to the relevant heat identification, material documents, physical material and agreed sampling / witness points. A final shipment inspection cannot recreate traceability that was lost during processing.

A Short MTC Clause for an Export Purchase Order

Practical Buyer Workflow

1. Before ordering: build the material and certificate requirements into both the RFQ and the purchase order.
2. Before production: approve the proposed mill source, grade, test plan and traceability approach.
3. Before processing: verify incoming plate heat numbers and MTCs against the order.
4. During processing: maintain controlled marking from plate to cut part, fabrication record and package.
5. Before shipment: reconcile MTC, marking list, dimensional / hardness reports, packing list and inspection report.
6. After shipment: retain the document package in the project file for installation, warranty and future replacement orders.