For end-users and EPC contractors, a flange’s material test certificate and related reports are its “legal documents” for compliance and quality. However, a complete certificate is far more than stating “ASTM A105” or “SS304.” Understanding how to interpret its key elements is a core skill for incoming inspection and supply chain risk mitigation.
Tier 1: Basic Chemistry and Mechanical Properties:
- Chemical Analysis Report: Must include both ladle analysis (for the melt heat) and product analysis (from the forging or prolongation). Comparing the two verifies if the composition shifted during manufacturing. Pay special attention to harmful elements like S and P content, and for stainless steels, the calculated Pitting Resistance Equivalent Number.
- Mechanical Properties Report: Includes yield strength, tensile strength, elongation, and reduction of area. The report should clearly state the specimen orientation (longitudinal/transverse), location (e.g., flange hub prolongation), and test temperature (ambient, design, or low temperature). For cryogenic flanges, the Charpy Impact Test report must include test temperature, specimen size, absorbed energy, and lateral expansion values.
Tier 2: Manufacturing and Heat Treatment Records:
- Heat Treatment Chart: For flanges undergoing quench & temper or normalizing, the supplier should provide a complete temperature-time chart, proving the process parameters met the specification.
- Proof of Same Heat Treatment Lot for Test Coupons: Mechanical test specimens must have been heat-treated in the same furnace charge as the product itself. This is a prerequisite for the data to genuinely reflect the product’s properties. The certificate should have a clear statement to this effect.
Tier 3: Special Application Certifications:
- NACE MR0175 / ISO 15156 Certification: For sour service (H2S containing). The certificate must prove the material’s chemistry, hardness, and heat-treated condition comply with requirements for Sulfide Stress Cracking resistance.
- PED 2014/68/EU Certification: For pressure equipment in the EU. Confirm that the flange or its manufacturer holds a valid EC Type-Examination Certificate or Module H1 certification covering the product’s specification range.
- Nuclear Grade Certification (e.g., RCC-M, ASME III): Imposes extremely stringent requirements on QA systems, material traceability, procedure qualification, and personnel qualification. Its certificate reflects systemic capability.
Risk Assessment: When a supplier only provides a generic “Certificate of Conformity” instead of detailed test reports tied to specific melt and heat treatment lots, the risk is high. Establish a system for third-party witness testing or verification for flanges in critical services.
Therefore, incorporating the depth of material certificate review into supplier pre-qualification and order technical agreements is the cornerstone of building a reliable supply chain.