The mill test certificate (MTC) is the core document at acceptance of stainless steel. Two common EN 10204 types:

• 3.1 certificate: issued by the manufacturer's inspection department, declaring conformity to the order and including measured chemical composition and mechanical properties. • 3.2 certificate: issued by an inspection body independent of the manufacturer, typically required for pressure, safety or customer-mandated applications.

What to check:

1) Heat/coil number matches the physical label and packaging. 2) Grade and standard match the order (e.g. 316L per ASTM A240 / 1.4404 per EN 10088-2). 3) Measured chemistry is within the standard range, especially Cr/Ni/Mo/C. 4) Mechanical properties (yield, tensile, elongation) meet the standard and any additional customer requirements. 5) Heat treatment/delivery condition and surface code are correct. 6) Signatures, authorised person, date and certificate number are present; a 3.2 certificate must identify the independent body.

Good practice: request traceable heat numbers and third-party retest reports; for critical parts, carry out your own PMI (spectrometer) verification.

Remember: a certificate is a declaration, not proof that the physical goods conform — incoming inspection and PMI remain necessary.