| 1. Manufacturing Process | Confirm whether the factory produces ERW, HFW, spiral-welded, longitudinally welded, seamless, or galvanized pipe. | Process description, production-line photographs, mill certificates, and factory audit records. | 15% | The process affects dimensional tolerance, pressure capability, wall-thickness consistency, and application suitability. |
| 2. Applicable Product Standards | Check the exact standards supported for each pipe type, grade, size, and end finish. | API 5L for line pipe; ASTM A53 for general-purpose steel pipe; ASTM A106 for seamless carbon-steel pipe at high temperature; EN 10219 for cold-formed welded structural hollow sections. | 15% | Standards define testing, chemical composition, mechanical properties, dimensions, and acceptance requirements. |
| 3. Material Grade Capability | Verify carbon-steel, low-alloy, stainless-steel, or other grades offered for the intended service. | Heat certificates, chemical-analysis reports, tensile-test results, yield-strength results, and impact-test records where required. | 12% | Correct grade selection is essential for pressure, temperature, corrosion, welding, and structural performance. |
| 4. Size and Wall-Thickness Range | Request the actual production range rather than relying on a general catalog. | Approved dimensional tables, calibrated measuring equipment, and sample inspection reports. | 10% | A supplier may stock standard sizes but outsource non-standard diameters, lengths, or wall thicknesses. |
| 5. Quality Management System | Confirm whether the certificate is current and applies to the manufacturing site used for the order. | ISO 9001 quality-management certification issued by an accredited certification body. | 10% | A documented quality system improves traceability, corrective action, process control, and repeat-order consistency. |
| 6. Testing and Inspection | Review the available destructive and non-destructive testing methods. | Hydrostatic testing, ultrasonic testing, eddy-current testing, radiographic testing, dimensional inspection, and visual inspection as specified by the purchase standard. | 12% | Testing capability helps detect weld defects, laminations, leaks, dimensional deviations, and material inconsistencies. |
| 7. OEM Customization | Evaluate custom lengths, beveling, threading, grooving, coating, marking, bundling, and private-label packaging. | Approved drawings, first-article samples, packaging specifications, and signed inspection criteria. | 10% | OEM flexibility reduces downstream processing and allows the product to match project or distributor requirements. |
| 8. Surface Treatment and Coating | Confirm galvanizing, painting, epoxy, polyethylene, or other coating options and the inspection method used. | Coating thickness records, adhesion tests where applicable, surface-preparation procedures, and relevant project specifications. | 8% | Proper surface treatment improves corrosion resistance, storage life, and field performance. |
| 9. Traceability and Documentation | Check whether each bundle or pipe can be linked to a heat number, production batch, test result, and shipping record. | EN 10204 inspection documents, heat numbers, mill test certificates, packing lists, and inspection release notes. | 5% | Traceability supports customs clearance, project acceptance, warranty claims, and quality investigations. |
| 10. Commercial and Export Performance | Compare quotation validity, minimum order quantity, lead time, payment terms, packaging, export documentation, and after-sales response. | Recent shipment records, customer references, pro forma invoices, delivery schedules, and third-party factory-audit reports. | 3% | The lowest unit price may not provide the lowest total cost after inspection, freight, delays, rework, and claims are considered. |