MTR and Compliance Documentation
The paperwork that turns a piece of steel into a documented compliant product. Mill test reports, manufacturer certifications, and compliance letters explained.
What Is a Mill Test Report
A mill test report (MTR), also called a mill certificate, is the document the steel mill issues with each heat lot. It shows the chemistry analysis (carbon, manganese, silicon, sulfur, phosphorus, plus alloying elements), the mechanical properties (yield strength, tensile strength, elongation, reduction of area), the heat treatment record, and any supplementary test results like charpy impact, NDE, or hardness. The MTR is keyed to the heat number, which is the unique identifier for that pour of steel.
EN 10204 3.1 vs 3.2
EN 10204 is the European standard that classifies inspection documents. A 3.1 certificate is issued by the manufacturer's own quality department, certifying that the product meets the order requirements with reference to test results performed on the actual material. A 3.2 certificate adds independent verification by either a customer-designated representative or a third-party inspector. 3.2 is required on some critical service applications. 3.1 covers the majority of industrial pressure service.
Domestic Melt Traceability
For BABA and AIS compliance, the MTR must show that the heat was melted at a domestic mill. This means the MTR carries the mill name and location, the heat number, and the date of pour. We pull from confirmed domestic-melt heat lots for BABA and AIS orders and the documentation chain stays intact through final fabrication.
Manufacturer Certification
A manufacturer certification (also called a certificate of compliance or COC) is a written statement from the manufacturer that the product was made in accordance with the order requirements. For BAA compliance, the manufacturer certifies domestic manufacture. For BABA and AIS, the manufacturer certifies that all manufacturing processes including the initial melt occurred in the United States.
Project-Specific Compliance Letters
For federal projects, the documentation package typically includes a project-specific compliance letter. The letter references the funding source (BAA, BABA, AIS, or ARRA), the specific contract or project number, and certifies that the supplied product meets the applicable domestic content standard. The letter is drafted to fit the project office submittal format.