| Material Grade and Standard | Confirm that the plate is identified as 316 or 316L stainless steel and that the applicable product standard is clearly stated. | Purchase specification, material certificate, product marking, and applicable standard reference. | Grade designation and product standard must match the purchase order and intended application. | Incorrect alloy chemistry, unsuitable corrosion resistance, or non-compliance with project requirements. | Required |
| Heat Number Traceability | Check whether every plate, bundle, or clearly defined plate group can be traced back to a specific melting heat. | Heat number on plate or tag, packing list, test certificate, and traceability register. | The heat number should remain legible and consistent across the plate, certificate, and shipping documents. | Loss of material identity and inability to link test results to the supplied plate. | Critical |
| Material Test Certificate | Review whether the certificate includes heat number, product dimensions, chemical composition, mechanical properties, delivery condition, and test results. | Manufacturer-issued certificate reviewed against the purchase order and inspection plan. | All mandatory fields are complete, internally consistent, signed or electronically validated, and traceable to the supplied material. | Unverified claims regarding composition, strength, heat treatment, or product conformity. | Critical |
| Chemical Composition | Verify chromium, nickel, molybdenum, carbon, manganese, silicon, phosphorus, sulfur, nitrogen, and iron balance as applicable. | Heat analysis and, where specified, product analysis recorded on the material certificate. | Reported values must fall within the limits of the specified material standard. 316L generally requires low carbon content, commonly not exceeding 0.03% by mass under applicable standards. | Reduced corrosion resistance, sensitization risk after welding, or use of an incorrect alloy. | Critical |
| Positive Material Identification | Determine whether alloy verification is performed using a suitable handheld or laboratory-based method, such as X-ray fluorescence, when required. | PMI procedure, instrument calibration record, test map, and individual or batch test results. | Results should distinguish the specified stainless steel grade from similar grades and be linked to the relevant heat or plate identification. | Mixing of 304, 316, 316L, or other stainless steel grades in the same delivery. | Recommended |
| Mechanical Testing | Review tensile strength, yield strength, elongation, and hardness results where required by the applicable standard or project specification. | Tensile test report, hardness report, specimen orientation, sampling location, and test method. | Results must satisfy the specified standard and should identify the test specimen and associated heat number. | Unexpected forming, welding, or service performance and possible structural non-conformity. | Required by Specification |
| Ultrasonic Examination | Confirm whether internal discontinuity testing is required for the plate thickness, service condition, or project class. | Ultrasonic testing procedure, operator qualification, equipment calibration, scan coverage, and examination report. | Acceptance level, scanning coverage, and reporting method should be defined before testing and applied consistently. | Undetected laminations or internal defects that may affect fabrication and service reliability. | Project-Specific |
| Dimensions and Thickness | Measure thickness, length, width, flatness, squareness, and edge condition using calibrated equipment. | Dimensional inspection report, calibrated gauge records, measurement locations, and approved tolerance reference. | Measurements must comply with the dimensional tolerances stated in the applicable product standard or purchase specification. | Cutting losses, fit-up problems, fabrication delays, or rejection at incoming inspection. | Required |
| Surface Condition | Inspect for corrosion, pitting, cracks, laminations, deep scratches, scale, contamination, and unacceptable grinding marks. | Visual inspection report, photographs, surface finish designation, and non-conformance records if applicable. | Surface condition and finish must match the ordered finish and contain no defects beyond the agreed acceptance criteria. | Reduced corrosion performance, additional finishing work, and premature rejection. | Required |
| Heat Treatment and Delivery Condition | Confirm whether the plate was supplied in the required solution-annealed or other specified condition. | Heat-treatment record, certificate statement, furnace identification, and applicable temperature or process information. | Delivery condition must be stated and consistent with the applicable product standard and purchase requirements. | Unstable microstructure, reduced corrosion resistance, or unsuitable mechanical properties. | Required by Specification |
| Testing Laboratory Competence | Evaluate whether testing is performed by competent personnel using calibrated equipment and recognized test methods. | Laboratory accreditation scope, equipment calibration certificates, personnel qualifications, and test procedures. | The laboratory should be competent for the specific test type, material, and standard cited in the inspection documentation. | Questionable or non-repeatable test results and disputes over product conformity. | Recommended |
| Inspection and Test Plan | Check whether inspection activities, hold points, witness points, responsibilities, and document requirements are defined before production or shipment. | Approved inspection and test plan, quality plan, inspection notification procedure, and signed inspection records. | The plan should cover document review, traceability, testing, dimensions, surface condition, release, and non-conformance handling. | Important inspections may be omitted or performed too late to correct defects economically. | Recommended |
| Sampling and Test Frequency | Verify how samples are selected and whether the sampling frequency is appropriate for the order, heat, plate thickness, and applicable standard. | Sampling plan, heat-based test matrix, specimen records, and test frequency requirements. | Sampling must be defined in advance and must not allow unrelated heats or plates to be represented by one test without authorization. | Non-representative results and undetected variation within the shipment. | Required by Specification |
| Non-Conformance Control | Assess how the supplier identifies, segregates, investigates, and resolves plates that fail inspection or testing. | Non-conformance report, root-cause analysis, corrective action, concession approval, and disposition record. | Non-conforming material must be physically or electronically controlled and cannot be shipped without documented approval. | Accidental delivery of rejected, repaired, downgraded, or mixed material. | Critical |
| Document Consistency | Cross-check heat numbers, plate numbers, dimensions, quantities, grade, finish, and shipping details across all documents. | Purchase order, certificate, packing list, inspection report, invoice, and shipping marks. | No unexplained differences should exist between physical markings and submitted documentation. | Customs delays, receiving disputes, material mix-ups, and traceability gaps. | Required |
| Packaging and Identification | Check whether the plates are protected from contamination, moisture, impact, and loss of identification during handling and transport. | Packaging specification, photographs before dispatch, durable tags, and loading inspection record. | Tags should remain legible, plates should be securely supported, and packaging should be suitable for the transport route and storage conditions. | Surface damage, contamination, corrosion staining, or loss of heat traceability. | Required |
| Pre-Shipment Release | Confirm that shipment is released only after required inspections, testing, document review, and corrective actions are complete. | Release note, final inspection report, approved certificate package, and signed quality release record. | The final documentation package should be complete and approved before dispatch unless a formally documented exception exists. | Receipt of incomplete, unapproved, or technically unverified material. | Critical |
