Material test certificates from Chinese mills are, in the majority of cases, accurate and traceable. The problem is not the mills. The problem is what happens between the mill gate and the factory floor.

The case

A pressure piping order for an offshore platform. Specified material: ASTM A333 Grade 6 seamless pipe, low-temperature service, impact tested to minus 45 degrees Celsius.

The factory submitted MTCs that showed heat numbers, chemical analysis, mechanical properties, and impact test results. Documentation looked complete.

What the spectrometer found

At a routine third-party PMI check during fabrication — not a specific hold point, just a spot check we include in all pipe fabrication scopes — the XRF spectrometer flagged two spools with a carbon content and manganese ratio inconsistent with A333 Gr.6. The readings were consistent with standard A53 Grade B.

A53 Grade B is a perfectly good pipe material. It is not rated for minus 45 degrees service. It does not meet the Charpy impact requirements for the low-temperature scope.

The factory's explanation

The pipe was mislabelled at the stock warehouse, not a deliberate substitution. That may well have been true. The outcome was the same: two spools rejected, replacement pipe required, three-week delay. The MTCs for the rejected spools were genuine documents — for different material.

Why PMI is not optional

On any scope where material grade has direct safety or performance implications — low-temperature piping, high-temperature service, sour service, rotating equipment shafts, pressure boundary forgings — PMI is a basic line item. The cost of a portable XRF unit and an inspection day is negligible against the cost of a discovery on the receiving wharf.

What we do

Meritus Technology includes PMI requirements in every RFQ for pressure piping, pressure vessels, and rotating equipment shafts. We can help you build it into yours.

Contact: sales@meritustech.com · +86 134 8206 1802 · www.meritustech.com