Quality you can document.
We treat a washer as a controlled part, not a commodity — material verified on the way in, dimensions checked against DIN and ASME, surfaces inspected, and the paperwork prepared so your goods-in and compliance teams have what they need to sign it off.
Five control points, from coil to carton.
Quality is checked at the stages where defects actually enter a washer — incoming material, forming dimensions, surface condition and packing. Here is what we look at and how.
Incoming material verification
Every lot of 304, 316 or 316L is received against its mill test certificate and matched to the heat / melt number. Positive material identification (PMI) by handheld XRF is available on request to confirm grade before parts are formed.
Dimensional inspection
Outer diameter, inner diameter, thickness and flatness are measured against the applicable standard — DIN 125 / 9021 / 433 / 127 or ASME B18.21.1 / USS / SAE — using calipers, micrometers, plug and go / no-go gauges, with first-article checks on new tooling.
Visual & surface check
Parts are inspected for burrs, cracks, deformation, tooling marks and finish consistency. Bright or polished surfaces are checked against the agreed condition so the lot looks and behaves uniformly in your assembly.
Salt-spray testing
For coastal-duty parts, neutral salt-spray (NSS) corrosion testing is available on request to verify corrosion performance. Useful when you are choosing between 304 and 316 / 316L for a marine or chemical environment.
Packing & quantity check
Before sealing, lots are verified for count, labeling, grade marking and export packing condition. Cartons and pallets are checked against the packing list and HS-code documentation so the shipment clears and reconciles cleanly at your dock.
Checked, then shipped
Inspection & documentationInspection results inform the documents you receive — so the certificate in the box matches the parts in the box.
We verify the metal, not just the dimensions.
Grade and hardness are checked on our own equipment — so 316 means 316, and the mechanical properties match the mill test certificate. This is how we stand behind genuine, full-specification material instead of asking you to take it on trust.
Documentation you can request.
Distributors and OEM buyers need more than a part — they need the paperwork that lets the part into a regulated supply chain. We prepare the records below; material and test documents are available on request and quoted with the order.
EN 10204 3.1 mill test certificate (MTC)
The 3.1 certificate ties your washers to a specific melt, with the chemical composition and mechanical properties of the stainless. The core traceability document for export and audited supply chains — available on request.
Dimensional inspection report
A measured report of the key dimensions — OD, ID, thickness — against the specified standard or your drawing, with the gauges and instruments used. Available on request, including first-article reports for new or custom tooling.
RoHS / REACH declaration
Material compliance declarations for restricted substances, to support CE-marked assemblies and EU-market shipments. Available on request for the relevant grade.
PPAP for automotive
Production Part Approval Process submission packages for automotive and Tier-1 customers — built around your specific part, level and submission requirements. Available on request; scope agreed at quotation.
Management-system certification
Our quality-management system is certified to ISO 9001:2015. Part-level material certificates (MTC / EN 10204 3.1) and the test reports above are available on request.
Quality management system
Certified to ISO 9001:2015 / GB/T 19001-2016 for the manufacturing and sales of stainless steel washers. Certificate No. 74326Q00174R001, issued by Origin Certification (Shanghai) — CNAS / IAF accredited — valid to 23 Apr 2029.
Automotive & Tier-1 programs
Our active management-system certification is ISO 9001:2015 (we are not IATF 16949 certified). For automotive and Tier-1 work we still support PPAP submission packages and full material / dimensional documentation on request — tell us your part and submission level.
We inspect to the standard you specify.
Tell us the standard — metric DIN or imperial ASME / USS / SAE — and we measure to its dimensions, tolerance class and surface condition. The reference tables we work from are published on our standards pages so you can specify with confidence.
| Inspection point | What we check | Method / tool |
|---|---|---|
| Material grade | 304 / 316 / 316L vs MTC | MTC review · PMI (XRF) on request |
| Outer diameter | OD vs standard / drawing | Caliper · micrometer |
| Inner diameter | ID & hole fit | Caliper · go / no-go gauge |
| Thickness | Gauge vs standard | Micrometer |
| Surface / finish | Burrs · marks · finish | Visual inspection |
| Corrosion resistance | Grade durability | Neutral salt-spray on request |
Tell us the documents your supply chain requires — a 3.1 MTC, a dimensional report, a RoHS / REACH declaration, a PPAP package or a salt-spray result — and we will confirm scope, format and cost with your quote.
Common questions about quality & documentation.
Straight answers to what export buyers and procurement teams ask most often.
Is HUIHUI ISO 9001 certified?
Yes. Certified to ISO 9001:2015 / GB/T 19001-2016 for the manufacturing and sales of stainless steel washers. Certificate No. 74326Q00174R001, issued by Origin Certification (Shanghai) — CNAS / IAF accredited — valid to 23 Apr 2029. The documented, traceable management system covers incoming material, production, inspection and dispatch. Download the certificate
Do you provide mill test certificates (MTC / EN 10204 3.1)?
Yes. Every lot is received against its MTC and matched to the heat/melt number — that traceability runs through to the certificate you receive. EN 10204 3.1 MTCs are available on request, quoted with the order. The certificate in the box corresponds to the parts in the box.
Do you run PMI (positive material identification)?
Yes. PMI by handheld XRF is available on request to confirm grade before parts are formed. Useful when 316 vs 304 verification is required at incoming inspection or for an audited supply chain. Quoted as part of the order.
How do you ensure dimensional consistency across a large production run?
The plant runs high-speed automated YANGLI and SHINGLI coil-fed presses straight off 304/316 stainless coil. High automation means the press sets the stroke — OD, ID and thickness stay consistent run-to-run without depending on operator adjustment. Dimensions are verified against the applicable DIN or ASME tolerance at multiple points, with first-article inspection on new or custom tooling.
How do you guarantee the material is genuine full-spec stainless?
We source from documented melts and stamp to full thickness from stainless coil — no under-gauge, no recycled substitution. Incoming lots are matched to MTCs by heat/melt number; PMI by XRF is available to verify grade independently. We supply only 304 (A2), 316 (A4) and 316L, bright or polished finish — no plating or coating that could mask off-grade base material.
What quality documentation can I request with an order?
Available on request: EN 10204 3.1 MTC, dimensional inspection report, PMI result, RoHS / REACH declaration, neutral salt-spray (NSS) test result, and PPAP packages for automotive / Tier-1 work. Scope and cost are confirmed with your quote — tell us what your supply chain or goods-in team needs.
Tell us what you need.
Send specs or a drawing and we will come back with pricing, lead time and material options. No account, no minimum to ask.
- ✓ 304 / 316 / 316L, DIN & ASME or custom
- ✓ Replies from engineers, typically within one business day
- ✓ Samples and material certificates available