Valve Quality Inspection in China: ITP and FAT Guide

A factory audit asks whether a supplier has a capable system. Order inspection asks whether the actual valves being manufactured meet the purchase order. This guide focuses on the second task: inspection and test planning from material receipt through final release.

Start with the purchase requirements

Create a controlled list of the valve schedule, data sheets, drawings, standards and editions, approved deviations, material specifications, testing, documentation and delivery requirements. Inspection cannot correct an ambiguous contract.

Build an inspection and test plan

The ITP should list each manufacturing stage, applicable procedure, acceptance criterion, record, responsibility and review, witness or hold point. Include notice periods and define what happens if an inspector cannot attend after proper notification.

Review documents before production

Check drawings, bill of materials, manufacturing route, welding and NDE procedures, heat treatment, coating procedure, pressure-test procedure, traceability plan and document index. Resolve comments before the affected operation begins.

Incoming-material inspection

Verify grade, product form, dimensions, condition, heat number and certificate against the approved bill of materials. Define PMI or additional tests where risk requires them. Quarantine material with missing or conflicting identity.

Traceability control

Sample the link from material certificate to cut piece, machined component, assembly traveler and completed valve tag or serial number. Include subcontracted heat treatment, hardfacing and NDE. Traceability should survive rework and replacement.

In-process dimensional inspection

Inspect critical dimensions at stages where defects can still be corrected: body wall, seat pockets, stem, bore, face-to-face, flange or weld ends, surface finishes and actuator interfaces. Use suitable calibrated equipment and record actual results where required.

Welding and repair

Confirm approved WPS, qualified personnel, filler control, preheat, interpass and postweld heat-treatment requirements. Review repair authorization, defect removal, reinspection and traceability. A repaired casting or overlay needs the specified records.

Nondestructive examination

Verify method, extent, procedure, personnel qualification, calibration, coverage and acceptance criteria. Review original reports and images where required. A statement that material was “UT tested” is incomplete without scope and result.

Assembly inspection

Check cleanliness, component identity, seat and seal condition, lubricant, packing, gasket, bolt tightening, stem movement, cavity-relief direction, actuator mounting and accessories. Confirm the assembled configuration matches the approved drawing.

Pressure and closure testing

Use the governing standard and purchase order for medium, pressure, duration, direction and leakage acceptance. Verify test gauges or transducers have suitable range, resolution and calibration. Record actual values and tie results to each valve.

Functional and actuator testing

Verify travel, direction, torque or thrust settings, limit and torque switches, local and remote controls, failure action, position indication, solenoids, positioners and accessories. Stroke-time tests need defined supply pressure, tubing and load conditions.

Factory acceptance test

A FAT combines agreed inspections and functional demonstrations before release. Prepare a test agenda, approved procedures and prerequisites. Record punch items, responsibility and closure evidence. A FAT should not replace required production inspections.

Coating and preservation

Inspect surface preparation, environmental conditions, batch data, thickness, cure, adhesion or holiday testing where specified, color and repair. Verify internal preservation, end covers, desiccant or wrapping and compatibility with seats and process.

Final documentation review

Confirm material certificates, inspection reports, NDE, heat treatment, pressure and functional tests, calibration records, coating records, nonconformance closure, drawings, manuals and certificates are complete and consistent with the delivered tags.

Pre-shipment inspection

Check quantity, identity, appearance, loose accessories, spares, markings, packaging, lifting points, dimensions and documents. PSI verifies release condition; it does not prove hidden manufacturing stages that were never inspected.

Third-party inspector selection

Select competence by valve type, materials, tests and destination requirements rather than agency name alone. Provide the complete order and ITP, define reporting format and ensure the inspector is independent of sales pressure.

Nonconformance control

Document the requirement, objective evidence, affected items and disposition. Rework or use-as-is decisions need authorized technical approval and reinspection. Extend the investigation to other valves or heats when the cause may be systemic.

Information Wofer needs

Send the approved ITP, inspection agency details, notice period, required procedures, acceptance criteria and report format with the order. Wofer can schedule production and inspection points against the actual scope.