Documentation Guide · EN 10204 3.1
A mill test certificate (MTC) — also called a material test report (MTR) — is the primary documentation Saudi Aramco requires for Goods Receipt of SAEP-347 piping materials. This guide explains what EN 10204 3.1 is, what it must contain, and why Gulf Union Ozone supplies original 3.1 MTCs with every delivery.
A mill test certificate (MTC) — also known as a material test report (MTR) or inspection certificate — is a document issued by the manufacturing mill confirming that a specific batch of material was produced, tested, and found to meet the applicable material specification. The MTC records the actual test results: the specific chemical composition of that heat lot, the actual mechanical test values (tensile strength, yield strength, elongation), and the heat treatment applied.
An MTC is not the same as a Certificate of Conformance (CoC). The two documents serve different purposes:
Issued by the producing mill. Records actual test data from the specific heat/lot: chemical analysis, mechanical tests, heat treatment. Proves material identity and physical properties. Required for Aramco Goods Receipt to confirm the material is what it claims to be.
Issued by the supplier or stockist. Declares that goods supplied conform to the purchase order specification — grade, size, standard, quantity, documentation requirements. References the PO number, material number, and accompanying MTC. Aramco requires both documents: the MTC for material identity, the CoC for order conformance.
For Saudi Aramco projects under SAEP-347, both documents are required at Goods Receipt. A CoC without an MTC — or vice versa — will not pass the GR inspection for SAEP-347 materials. Gulf Union Ozone provides both original EN 10204 3.1 MTCs and Certificates of Conformance with every SAEP-347 order.
"An EN 10204 Mill Test Certificate (MTC) is the fundamental document that establishes traceability between a physical product and its manufacturing test results. For Saudi Aramco Goods Receipt under SAEP-347, only EN 10204 Type 3.1 or 3.2 documents are accepted. Type 3.1 is signed by an authorised inspection representative of the manufacturer — a qualified individual independent of the production department, whose identity and credentials appear on the certificate. Type 3.2 is co-signed by a third-party inspection body (SGS, Bureau Veritas, Lloyd's Register) and is required for safety-critical applications including high-alloy piping in sour service. Type 2.2 (manufacturer's test report, self-certified by the production department) and Type 2.1 (simple declaration of compliance with no test data) do not meet Aramco's GR documentation requirements. Submitting a Type 2.2 where a 3.1 is specified results in immediate GR rejection and return of the entire shipment pending re-documentation."
EN 10204:2004 is the European standard (internationally adopted across the Middle East, Asia, and Africa) that defines the types of inspection documents that can accompany metallic materials. It specifies four inspection certificate types — each representing a different level of independent validation. For Saudi Aramco projects, the minimum required type is EN 10204 3.1. See also our complete EN 10204 guide for a full breakdown of all certificate types and their Aramco project applicability.
| Type | Name | Validated By | Who Issues | Aramco SAEP-347 |
|---|---|---|---|---|
| 2.1 | Declaration of conformance | None (declaration only) | Manufacturer | ❌ Not accepted |
| 2.2 | Test report | Manufacturer (no specific inspector) | Manufacturer | ❌ Not accepted |
| 3.1 | Inspection certificate | Manufacturer's own qualified 3.1 inspector | Manufacturer | ✅ Required minimum |
| 3.2 | Inspection certificate | Manufacturer's inspector + independent third party | Manufacturer + TPI body | ✅ For critical items (TPI required) |
Why 3.1 is the minimum for Aramco: An EN 10204 3.1 certificate is validated by a qualified inspection representative of the manufacturer — a role with documented qualifications and personal accountability. The inspector's name, qualifications, and signature appear on the certificate. This creates a traceable, accountable certification chain from mill to Goods Receipt. A 2.2 report is issued by the manufacturer without a specifically qualified and identified inspector — offering no independent validation.
A 3.2 certificate involves a qualified third-party inspector (from SGS, Bureau Veritas, Lloyd's Register, etc.) who independently witnesses the testing and co-signs the certificate. Aramco may require 3.2 for safety-critical applications — check your project specification or Inspection and Test Plan (ITP).
"EN 10204 offers four certificate types based on validation independence. Type 2.1 (Declaration of Conformance) is self-issued by the manufacturer with no test data — the lowest level, unacceptable for any Aramco project material. Type 2.2 (Test Report) includes actual test results but is self-certified by the manufacturer's production department and lacks independent validation. Type 3.1 requires a manufacturer-appointed inspection representative who is organisationally independent of production — the representative's name, qualifications, and signature must appear on the certificate alongside the mill heat number and test results. Type 3.2 adds a co-signature from a third-party inspector nominated by the purchaser, providing the highest validation level. For all SAEP-347 materials, specify '3.1 MTC per EN 10204' in your Purchase Order requisition line. Gulf Union Ozone supplies Type 3.1 as standard on every SAEP-347 shipment; Type 3.2 with SGS or Bureau Veritas is available on request."
An EN 10204 3.1 certificate must include specific fields. Aramco GR inspectors check each field against the physical item and the purchase order. Missing or incorrect fields are grounds for rejection. Gulf Union Ozone supplies original 3.1 MTCs that include all of the following fields on every SAEP-347 material delivery.
The actual producing mill — the facility that manufactured and tested the material. This must be the mill, not the stockist. Aramco GR inspectors cross-reference the manufacturer name against approved suppliers where applicable.
The exact specification the material was manufactured to — e.g., ASTM A105 for carbon steel flanges, ASTM A234 WPB for butt weld fittings, API 600 for gate valves. Must match the Aramco material number's Annex 4 specification exactly. If A105N (normalized) is specified, the MTC must confirm normalization.
The unique identifier assigned by the steel mill to a specific melt or production batch. This number is the critical traceability link — it must appear on both the MTC and the physical marking on every item in that heat lot. Mismatched heat numbers between MTC and item marking are the most common cause of Aramco GR rejection.
The MTC must show actual results — not "per specification" or "typical values." For ASTM A105 carbon steel, the certificate must list the actual percentage of each element: Carbon (C), Manganese (Mn), Phosphorus (P), Sulfur (S), Silicon (Si), and may include Copper (Cu), Nickel (Ni), Chromium (Cr), Molybdenum (Mo), and Vanadium (V). Each element is shown with its specification minimum/maximum and the actual measured result.
Again, actual results are required — not specification limits. Minimum fields: Ultimate Tensile Strength (UTS), Yield Strength (0.2% proof stress), Elongation (%), and Reduction of Area (%). Hardness (Brinell HB or Vickers HV) is required where specified by the material standard. For sour service materials, Charpy impact test results at specified temperatures are also required.
Normalized, annealed, quenched and tempered (Q&T), or as-forged — whichever is applicable. This is critical for materials where the heat treatment determines properties (e.g., A105N normalized flanges, alloy steel A182 F11 normalized + tempered).
This is what distinguishes a 3.1 certificate from a 2.2 report. A qualified inspection representative — employed by the manufacturer, independent of the production department, with documented qualifications — must sign the certificate. The inspector's full name and title must be legible. A photocopied, stamped, or scanned signature without the original is not acceptable for Aramco GR. Missing or illegible signatures are among the most common documentation rejection causes.
"An EN 10204 3.1 certificate must contain eight mandatory elements to satisfy Aramco GR: (1) the certificate number, (2) the heat/melt number traceable to the melt from which the product was manufactured, (3) the product specification (ASTM grade and ASME B16 standard), (4) actual chemical composition from mill analysis showing values for all relevant elements, (5) actual mechanical test results (tensile strength, yield strength, elongation, and Charpy impact where the specification requires it), (6) the inspection representative's name, qualifications, and original signature, (7) the manufacturer's stamp or official seal, and (8) the delivery condition (normalized, annealed, solution-annealed, or as-rolled). At Aramco Goods Receipt, inspectors check all eight elements before accepting the delivery. A certificate missing any single element — most commonly a missing inspector signature or unspecified delivery condition — results in GR rejection. Gulf Union Ozone reviews every MTC against these eight criteria before dispatch."
A heat number is a unique alphanumeric identifier assigned by the steel mill to a specific melt of steel. Each melt is a distinct pour — a single batch of liquid metal from the furnace, cast into billets, rolled or forged into products, and tested as a unit. All items produced from the same heat share the same chemical composition and the same MTC.
The traceability chain runs from mill to project site in three steps:
PMI (Positive Material Identification): For alloy steel materials (e.g., ASTM A182 F11 Cr-Mo flanges), Aramco may require PMI verification using a handheld XRF (X-ray fluorescence) spectrometer at GR. The PMI instrument measures the actual elemental composition of the item's surface and confirms it matches the alloy specified on the MTC. A carbon steel item that was incorrectly marked as alloy steel will fail PMI. Gulf Union Ozone's mill supply chain for stocked alloy materials is controlled to prevent material mix-ups.
Material traceability is auditable under Gulf Union Ozone's ISO 9001:2015 quality management system (QMS). Heat number records are maintained per our QMS document control procedures.
"Heat number traceability is the linkage between every physical item in a shipment and its originating mill melt/heat. For SAEP-347 materials, the heat number stamped or stencilled on the physical item must match the heat number on the EN 10204 3.1 MTC exactly — a single digit discrepancy causes rejection. At Aramco Goods Receipt, inspectors verify this match for 100% of SAEP-347 line items; there is no sampling concession for high-volume deliveries. If a heat number is unreadable due to surface damage, or inconsistent with the MTC, the item fails GR and must be returned to the supplier. For alloy steels, Positive Material Identification (PMI) via handheld XRF spectrometer is used as an additional check to confirm the chemical composition matches the MTC's declared analysis. Gulf Union Ozone maintains heat number records in our ISO 9001:2015 QMS warehouse system, enabling post-shipment traceability queries and a 10-year document archive."
All 59 SAEP-347 Annex 4 material numbers require full MTC documentation. Gulf Union Ozone stocks the most commonly specified SAEP-347 materials and supplies original EN 10204 3.1 MTCs with every delivery. The table below shows the MTC type required by product family for SAEP-347 materials from Gulf Union Ozone:
| Product Type | Key Standard | MTC Type Supplied | TPI Available |
|---|---|---|---|
| Gate valves, ball valves, check valves, butterfly valves | API 600, API 6D, API 608 | EN 10204 3.1 | Yes (SGS / BV / LR) |
| Carbon steel flanges (weld neck, slip-on, blind) | ASME B16.5, ASTM A105 | EN 10204 3.1 | Yes |
| Butt weld and socket weld pipe fittings | ASTM A234 WPB, ASME B16.9 | EN 10204 3.1 | Yes |
| Carbon steel and alloy pipes | API 5L, ASTM A106 Grade B | EN 10204 3.1 | Yes |
TPI = Third-Party Inspection. Gulf Union Ozone coordinates TPI through SGS, Bureau Veritas (BV), and Lloyd's Register at the origin mill or at our Jeddah warehouse. TPI requirement must be specified at RFQ stage to be included in the delivery timeline and quotation.
Documentation rejection at Aramco Goods Receipt delays projects and incurs significant expediting costs. The following are the most common documentation-related GR rejection causes and how Gulf Union Ozone prevents each one.
Prevention: Gulf Union Ozone only purchases from mills that issue 3.1 certificates. The MTC type (3.1) is confirmed before accepting materials into stock. Our supplier qualification process requires 3.1 capability for all SAEP-347 stocked items.
Prevention: Gulf Union Ozone QC team cross-checks the heat number stamped on each item against the MTC heat number before dispatch. Any discrepancy triggers a hold until resolved. We do not dispatch items without confirming heat number traceability.
Prevention: Our QC review confirms that all chemical and mechanical fields on the MTC contain actual numeric results. Certificates showing "meets requirements" or "per ASTM A105" instead of measured values are rejected and not forwarded.
Prevention: We only accept original certificates with a legible inspector signature and printed name. Photocopies are not accepted into our supply chain — only originals are forwarded. Scanned or digitally stamped signatures are only accepted if the mill provides an authenticated digital signature with a verifiable chain.
Prevention: The specification on the MTC (e.g., ASTM A105N vs ASTM A105) is confirmed against the project's Aramco material number specification at order entry. If the PO calls for A105N and the MTC only certifies A105, we resolve this with the mill before dispatch.
Prevention: Gulf Union Ozone's supply chain is direct-from-mill for all stocked SAEP-347 materials. We do not source from traders who may supply photocopies. Only original certificates leave our warehouse.
Yes — original EN 10204 3.1 MTCs from the producing mill, with actual chemical analysis and mechanical test values, heat number, and 3.1 inspector's signed credentials. We do not supply photocopies. Certificates of Conformance referencing the PO and Aramco material number are also included.
Yes. We coordinate TPI through SGS, Bureau Veritas (BV), and Lloyd's Register — at the origin mill or at our Jeddah warehouse. Specify TPI requirement in your RFQ so we can include the inspection schedule in the delivery timeline.
Read the heat number stamped or stencilled on the item and locate it in the "Heat/Lot Number" field of the MTC. Both must match exactly. For alloy steels, PMI via handheld XRF spectrometer is used for additional chemical composition verification.
EN 10204 3.1 requires a manufacturer's qualified 3.1 inspection representative to validate and sign the certificate — creating personal accountability. ASTM A6 is a product specification for structural steel that includes test requirements but does not define an equivalent inspector qualification role. For Aramco SAEP-347 projects, EN 10204 3.1 is the specified documentation standard.
Every Gulf Union Ozone delivery for Aramco projects includes original EN 10204 3.1 MTCs and Certificates of Conformance. Include in your RFQ: Aramco material number (6000XXXXXX format), quantity, delivery location, and documentation requirements (EN 10204 3.1 MTR + CoC, and TPI if required). We respond within 4 business hours.