# Metal Part Inspection Report Explained > Learn to review a metal part quality certificate: traceability, chemistry, porosity, CAD deviation, mechanical and thermal results, and conformance. Canonical: https://mesh2metal.com/guides/reading-a-metal-part-quality-certificate A metal part quality certificate is easiest to review as seven checks: identity, chemistry, porosity, CAD deviation, mechanical properties, thermal properties, and conformance. For each check, compare the reported value with a stated requirement, such as ±0.10 mm, rather than accepting a generic “pass” label. ## What should identification and traceability show? Identification and traceability establish exactly which part the certificate covers. Look for part number, drawing revision, material grade, finish condition, quantity, lot or batch identifier, order reference, inspection date, and document revision. Names should match the purchase order and drawing; the right grade with the wrong revision is not enough. Traceability should connect every result to the same lot. Confirm any serial or lot range, sample scope, and listed exceptions. If one certificate covers several items, check how each item is distinguished and retain the certificate with the drawing revision used for acceptance. ## How should chemical composition be compared with a material specification? Chemical composition should be compared element by element with the specified grade. Compare lower and upper bounds using the same units and basis, often weight percent. A value inside every range supports grade identity, but does not by itself prove suitability for service. Check alloy designation, condition, specification revision, inequality symbols, significant digits, and whether an element is reported as a balance. Do not judge from one headline element. Silicon may be in range while magnesium or iron is outside. Treat an omitted element as an open question, not an assumed pass. ## What do porosity and defect maps tell you? Porosity and defect map data describe void size, amount, and location. A pore-size value usually means the diameter or longest dimension of one void. Volume fraction means total void volume divided by evaluated material volume, expressed as a percentage. Many small pores can have low individual size but meaningful total fraction; one larger pore can control acceptance. A porosity report for additive parts should also identify depth, clustering, distance from critical surfaces, and any defined exclusion zones. No universal limit applies. Use the drawing, customer specification, or purchase-order requirement: a limit may set maximum pore size, maximum volume fraction, minimum ligament, or prohibited regions. Compare the map with those criteria, not with a color legend alone. ## How do you read 3D deviation from CAD? 3D deviation from CAD shows signed difference between evaluated surface and nominal geometry. Confirm alignment method, datums, excluded regions, and units before reading the color map. A tolerance band of ±0.10 mm means values from -0.10 to +0.10 mm meet that band; colors outside the legend need location-specific review. Mean deviation summarizes average bias, not worst case. Review maximum positive and negative values separately, along with the fraction of area outside tolerance and any functional surfaces. An acceptable mean can hide a local 0.30 mm excursion. ## Which mechanical properties belong on the certificate? Mechanical properties usually include tensile strength, yield strength, elongation, and hardness. Tensile strength is peak stress before fracture; yield strength marks a specified permanent-deformation threshold; elongation indicates ductility; hardness provides a localized resistance value. Check required minimum or range, units, material condition, test temperature, and specimen direction when relevant. Tensile testing is commonly reported to ASTM E8/E8M or ISO 6892-1\. Hardness needs a named scale, such as Rockwell B or C, Brinell HBW, or Vickers HV; a bare number is incomplete. Compare like with like: MPa and ksi are not interchangeable, and hardness scales need a stated conversion basis. ## What should thermal properties mean? Thermal properties commonly include conductivity and coefficient of expansion. Conductivity, reported in W/m·K, indicates how readily heat moves through the material. Expansion, often reported in µm/m·K or 1/K, indicates dimensional change with temperature. Check temperature range, direction, material condition, and test method when the design depends on a narrow operating window. Compare values with your design allowance, not a generic material chart. Expansion matters at interfaces and over long dimensions; conductivity matters in heat paths and steady-state thermal calculations. ## What does a certificate of conformance confirm? A certificate of conformance is the supplier’s formal statement that identified metal parts meet the purchase order, drawing, specification, and listed exceptions. Check issuing authority, date, part and revision, quantity, lot, governing requirements, and disposition of deviations. A signature without scope is weak evidence. Conformance does not replace underlying results. Chemistry, maps, dimensional summaries, property data, and traceability should support the statement. If the document says “conforms except,” read every exception and obtain written approval before acceptance. ## Example: how can a reviewer summarize the evidence? The following table is a fictional example only. Values are illustrative and must be replaced with the requirements for the actual part. | Section | Example reported result | Example requirement | Reviewer reading | | ---------------- | ------------------------------------------------------------------------ | ------------------------------ | ----------------------- | | Identification | Part MP-EX-042, drawing Rev C, lot EX-001 | Purchase order lists the same | Identity matches | | Composition | Si 11.7 wt%; Mg 0.3 wt% | Si 10.0–13.0 wt%; Mg ≤0.5 wt% | Shown ranges pass | | Porosity and map | Largest pore 0.18 mm; volume fraction 0.06%; no critical-zone indication | ≤0.25 mm; ≤0.10%; none in zone | Meets example criteria | | CAD deviation | Mean +0.03 mm; maximum +0.09/-0.08 mm | Tolerance band ±0.10 mm | Extrema are inside | | Tensile | 320 MPa tensile; 180 MPa yield; 4.5% elongation | ≥300; ≥160; ≥3.0% | Listed minima pass | | Hardness | 92 HBW | 80–105 HBW | Scale and range present | | Thermal | Conductivity 150 W/m·K; expansion 22 µm/m·K | ≥140; 20–24 | Example limits pass | | Conformance | Signed for Rev C and lot EX-001 | Statement required | Scope is complete | When a result is outside a requirement, pause acceptance. Check transcription, units, revision, test scope, and whether the limit applies to the whole part or a defined region. Then request a corrected certificate, formal deviation disposition, or reinspection as appropriate. Record the decision and approver; do not turn an exception into a pass by averaging unrelated results. Strong review connects three records: the purchase order or drawing, the certificate, and any approved deviation. That chain gives design, quality, and procurement a shared acceptance record and makes future lot review faster. For an overview of the records Mesh2Metal includes, see [quality documentation](https://mesh2metal.com/quality). ## Questions Can one certificate cover several identical parts? Yes, when the document clearly identifies the lot or quantity covered and the applicable drawing revision. Request separate identification when parts have different revisions or requirements. What if my drawing has no porosity limit? Ask the responsible design or quality authority to define an acceptance rule before release. A general certificate statement cannot create a limit that the drawing does not state. Should the certificate list the drawing revision? Yes. The revision ties the acceptance decision to the requirements used for review. Request a correction if the revision is missing or conflicts with the drawing. Are hardness values interchangeable across scales? No. Rockwell, Brinell, and Vickers use different scales. Require the named scale and a documented conversion when comparison is necessary. Sources (3) 1. \[1\] [ Porosity ](https://en.wikipedia.org/wiki/Porosity) , Wikipedia 2. \[2\] [ Certificate of conformance ](https://en.wikipedia.org/wiki/Certificate%5Fof%5Fconformity) , Wikipedia 3. \[3\] [ Geometric dimensioning and tolerancing ](https://en.wikipedia.org/wiki/Geometric%5Fdimensioning%5Fand%5Ftolerancing) , Wikipedia ## Check your part now. 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