How to Audit a Valve Factory in China: Buyer Checklist

A useful valve-factory audit verifies whether the organization, people, equipment and records can consistently deliver the valves in your specification. It should test real traceability and process control, not merely tour a clean workshop or collect certificate copies.

Define the audit scope

State the valve types, materials, sizes, pressure classes, manufacturing processes, standards, project risks and expected order volume. Decide whether the audit covers quality-system capability, technical capability, social compliance, cybersecurity, finance or a specific production order.

Prepare an evidence request

Request the business identity, organization chart, quality manual, process map, current certificates, product licenses where applicable, approved supplier list, equipment list, calibration status, welding qualifications, NDE qualifications, recent nonconformances and sample order records.

Verify certificates independently

Check certificate number, legal entity, site address, scope, issue and expiry status with the certification or licensing body. A valid ISO 9001 certificate does not prove a particular valve meets API, CE or project requirements, and one site’s certificate may not cover another factory.

Confirm what is made in-house

Map casting or forging, heat treatment, machining, hardfacing, assembly, pressure testing, coating and packing. Identify subcontracted processes and inspect how suppliers are approved, purchase requirements are transmitted and incoming results are verified.

Trace one real valve

Select a finished or in-process valve and trace its tag or serial number backward through test record, assembly traveler, component heat numbers, material certificates, machining and incoming inspection. Then trace one material heat forward to every affected item. This is more revealing than reviewing a prepared sample dossier.

Raw-material control

Inspect segregation, identification, quarantine, preservation and issuance. Review how alloy mix-ups, certificate review and positive material identification are controlled. Confirm cut pieces and remnants retain identity.

Machining and dimensional inspection

Check whether machines, fixtures and measuring equipment can achieve the required dimensions and finishes. Sample a measurement, verify instrument calibration status and observe how inspection results are recorded and out-of-tolerance conditions are handled.

Welding and heat treatment

Compare actual welding with the approved WPS, filler control and welder qualification. Review preheat, interpass and postweld heat-treatment records where required. For outsourced heat treatment, verify load traceability and furnace-calibration or uniformity evidence specified by the project.

Assembly controls

Observe cleanliness, component verification, seat and seal handling, lubricant control, bolt tightening, torque tools, stem and packing assembly, actuator alignment and work instructions. Check whether rejected parts can accidentally return to production.

Pressure and functional testing

Review test procedures, medium, pressure, duration, leakage criterion, safety barriers and data recording. Confirm gauges and transducers have suitable range, resolution and calibration. Witness a real test where possible, but do not treat one successful demonstration as proof of the whole system.

NDE capability

Verify procedures, personnel certification, equipment, consumables, lighting, calibration blocks, report traceability and acceptance criteria. If NDE is subcontracted, review supplier approval and how raw data and reports are controlled.

Nonconformance and corrective action

Sample recent nonconformance reports rather than only asking whether problems occur. Strong systems identify causes, contain affected product, approve disposition, verify rework, assess other lots and test whether corrective action prevented recurrence.

Document control and change management

Check that current drawings, specifications and standards reach production, while obsolete versions are removed. Review how customer changes, approved deviations and supplier changes are authorized and linked to the order.

Capacity and lead-time evidence

Compare quoted output with machine loading, shifts, bottleneck processes, subcontractor capacity, inspection time and current backlog. Ask for a milestone schedule. A large workshop alone does not prove that the promised delivery date is achievable.

Virtual versus on-site audits

A live virtual audit can verify documents and selected processes, but camera control, connectivity and preselected routes limit evidence. Use it for screening or follow-up. Critical or complex orders may justify an on-site or independent third-party assessment.

Audit report and follow-up

Classify findings by risk, cite objective evidence, assign owners and due dates, and require corrective-action evidence before approval where necessary. Supplier approval should be conditional on the products and processes actually assessed, with re-evaluation triggered by major changes or poor performance.

Planning an audit with Wofer

Send the proposed agenda, product scope, document list, auditor names and required evidence in advance. Wofer can confirm access, production availability and any confidentiality or safety arrangements before the audit date.