Most incoming MTC reviews at fabrication shops follow the same unwritten shortcut: check that the grade looks right, scan the yield and tensile values to confirm they're above the minimum, and file the cert. If nothing obviously wrong jumps out, the material goes to the floor.
That process catches maybe 40% of the issues that a complete MTC-to-PO validation would catch. The other 60% — wrong heat numbers, grade mismatches between the PO and what was shipped, supplementary requirements that were invoked but not performed, dimensional compliance not documented — clear incoming undetected and surface downstream.
A complete validation isn't more complex than the shortcut. It's a structured checklist, and it takes 8–12 minutes per cert done manually. Done with automated comparison software, it takes under a minute.
The Complete Validation Checklist
1. Product Specification and Grade
The MTC's stated product specification and grade must match the PO. This is the most basic check and still the most commonly missed one in practice. The MTC should show the exact specification (ASTM A572, ASME SA-516, API 5L) and grade (Grade 50, Grade 70, Grade X52). Verify both. A cert that shows A572 Grade 42 against a PO for A572 Grade 50 has a grade mismatch — the material delivered does not meet the minimum yield of the ordered grade.
2. Heat/Melt Number Presence and Format
The MTC must show a heat number (also called melt number, cast number, or charge number depending on the mill). This should be a unique alphanumeric identifier. Verify the field is populated, the format is plausible (not a test entry like "000000" or "N/A"), and the heat number matches any paperwork that arrived with the physical material (bundle tags, packing list, purchase records from the service center).
3. Chemistry Values vs. Specification Limits
For each reported element, the MTC value must fall within the limits specified by the product standard. For A36 plate, check carbon (max 0.25% for plate over 3/4"), manganese (0.80–1.20% for plate over 3/4"), phosphorus (max 0.04%), sulfur (max 0.05%), silicon (0.15–0.40% when controlled). For alloy and high-strength grades, the element list is longer and the limits tighter. Every element should be checked against the applicable table — not just the ones that historically cause problems.
4. Mechanical Properties vs. Specification Limits
Minimum yield strength, minimum tensile strength, and minimum elongation at minimum — all three must meet spec minimums. For some specifications, tensile strength has a maximum as well as a minimum (A36 has a 58–80 ksi tensile range; material above 80 ksi is also nonconforming). Check thickness-dependent requirements: some specifications have reduced yield minimums for material over a certain thickness, and the review needs to apply the correct limit for the actual thickness.
5. Test Method Compliance
The MTC should reference the test method standard used for mechanical testing. For ASTM plate, this is typically ASTM E8 (tension testing) and ASTM E23 (Charpy impact testing, if applicable). For ASME materials, the corresponding ASME test methods. If the cert doesn't reference a test method, the reviewer cannot confirm the tests were performed to the applicable procedure. Some customer quality plans require explicit test method references; others don't. Know which applies to your work.
6. Supplementary Requirements
If your PO invoked supplementary requirements (Charpy impact testing, vacuum treatment, UT examination, product analysis, simulated PWHT, carbon equivalent), every invoked requirement must appear on the MTC with the associated test result or compliance statement. Missing supplementary requirement documentation is a common gap on certs sourced from service center inventory — the material may meet base spec but wasn't ordered or tested to the supplementary requirements.
7. Heat Treatment Condition
When the product specification requires a specific delivery condition (normalized, Q&T, stress relieved, as-rolled when as-rolled is specified), the MTC must document it. For normalized plate, the cert should state the normalizing temperature range and confirm the heat treatment was applied. For Q&T material (A514, A517, A709 HPS grades), the quench-and-temper process should be documented with temperature ranges. When a delivery condition is missing from a cert for a spec that requires it, the material is unacceptable regardless of mechanical values — the values may have been tested in a different condition than the material was actually produced in.
8. Quantity, Dimensions, and Product Form
The MTC should reference the product form (plate, bar, structural shape, pipe, tube) and dimensions that match what was ordered and physically received. Compare plate thickness, width, and length on the cert against the PO and packing list. A cert for 1/2" x 96" x 240" applied to 3/4" x 96" x 240" plate is not valid — the heat number and chemistry may be correct, but the cert doesn't cover the material you received.
Where Manual vs. Software Validation Diverges
A trained quality engineer doing manual validation can execute this checklist in 8–12 minutes per cert. For an operation receiving 50 MTCs per week, that's 7–10 hours of QE time per week. That time isn't available in most shops without dedicated incoming inspection staffing.
In practice, manual validation gets compressed. The chemistry check gets skipped because "the supplier always gets the chemistry right." The supplementary requirements check gets skipped because "we don't usually invoke those." The heat treatment condition check gets skipped because it's a structural grade and heat treatment wasn't specified on the PO.
Automated validation runs the complete checklist on every cert, every time, in under a minute. The software doesn't compress the checklist under schedule pressure. The result is systematic coverage of all eight validation points rather than the three that the manual reviewer remembers to check.
For operations making the transition, a common path is: implement automated validation for the chemistry and mechanical property checks first (highest ROI, most quantifiable catch rate), add PO-to-MTC grade and spec comparison second, then layer in supplementary requirement tracking as the PO data structure supports it.