The short answer
Sourcing medium and high pressure valves from China is won not on price pressure but on writing the requirement clearly, verifying the supplier and locking down the documentation. The checklist below covers mandatory RFQ data, supplier evaluation, document verification, common pitfalls and lead times, and can be used as a purchasing template.
1. Mandatory RFQ data (omitting any item can produce a wrong price)
- Valve type: ball / gate / globe / butterfly / check / plug valve, etc.
- Size: DN or inches.
- Pressure class: ASME Class (150/300/600/900/1500/2500/4500) or PN (10/16/40/100/160/250/420).
- End connection: flanged (RF/RTJ/FF), butt weld (BW), socket weld (SW), threaded (NPT or BSP — the two are not interchangeable).
- Material: body (WCB/LCB/CF8M/duplex/WC6/WC9), trim and seating surfaces (Trim number, Stellite 6, PTFE/PEEK).
- Operating conditions: medium, temperature range, pressure, whether solids are present, whether H₂S is present (sour service).
- Operation: manual / pneumatic / electric / hydraulic; actuator voltage, air supply pressure, control signal.
- Standards: product standard (API 6D / API 600 / API 609, etc.) and test standard (API 598 / ISO 5208).
- Leakage class: soft seat Rate A, metal seat Rate C/D.
- Certification and documentation: CE/PED, API Monogram, EN 10204 3.1/3.2, ITP, third-party inspection.
2. Supplier evaluation (first establish factory or trader)
- Whether the business licence scope includes "production/manufacturing"; cross-check on gsxt.gov.cn.
- Key equipment list and calibration records (CMA/CNAS), and qualifications for outsourced casting, forging and heat treatment.
- ISO 9001 / API Q1 certificates must be verifiable on the issuing body's website; for the API 6D monogram, check the certificate number and validity.
- Whether the test bench is dedicated and can record each valve against its serial number.
- Whether PMI (XRF/OES spectroscopy) capability exists, and whether stainless and alloy parts are material-verified batch by batch.
3. Document verification (the biggest risk area)
- Serial number consistent in four places: nameplate, MTC material certificate, pressure test report and packing list.
- Date logic: material date < production date < pressure test date < shipment date.
- Testing body accreditation (CNAS/CMA) and report numbers must be verifiable.
- Beware of "one certificate set for everything"; require heat number (Heat No.) traceability for each batch.
4. Common pitfalls (negative list)
- Relying on a verbal "standard valve" agreement without signing a technical agreement.
- Accepting the lowest price without checking material certificates, so 304 is passed off as 316.
- Pressure test records not tied to serial numbers, making field leakage untraceable.
- Packaging not compliant with ISPM 15, leading to rejection by the destination country.
- Supplier audits performed as a formality, with bulk goods not matching the sample.
5. Purchasing process and lead time
RFQ → quotation and technical clarification → ITP/drawing/datasheet approval → production → third-party inspection (SGS/BV/TUV) → FAT → final documentation → shipment. Standard lead time for medium and high pressure valves is 4–10 weeks, depending on material, certification and pressure test requirements; EPC projects should allow time for document approval.
6. Five trust documents (recommended with every quotation)
Certificates, material certificate MTC (3.1/3.2), pressure test report, ITP (inspection and test plan), and references/case list.
For a fillable RFQ template and supplier evaluation scorecard, contact us for the full procurement checklist.