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
We check the grade of incoming 304, 316 and 316L coil with our own handheld XRF spectrometer (positive material identification, PMI), and can include the reading with your order.
Dimensional inspection
Outer diameter, inner diameter and thickness are measured against the applicable standard — DIN 125 / 9021 / 433 / 436 or ASME B18.21.1 / USS / SAE — with calipers, with first-article checks on new tooling.
Visual & surface check
Parts are inspected for burrs, cracks, deformation, tooling marks and surface consistency. The sawdust tumble-polished surface is checked so the lot looks and behaves uniformly in your assembly.
Hardness check
Sample parts are checked on our own Rockwell hardness tester as a mechanical-property check on the stamped material.
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. Piece count is checked by weight on an electronic scale.
Checked, then shipped
Inspection & documentationInspection results inform the documents you receive — so the report 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. 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. The records below are available on request.
PMI grade reading
The reading from our own handheld XRF spectrometer, confirming 304, 316 or 316L, can be included with your order. We do not issue EN 10204 3.1 mill test certificates: our coil suppliers do not pass on the steel mill’s certificate.
Dimensional inspection report
A measured report of the key dimensions — OD, ID, thickness — against the specified standard or your drawing. Available on request.
Management-system certification
Our quality-management system is certified to ISO 9001:2015. The PMI reading and the dimensional report 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 work, send us your part drawing and the documents your customer requires, and we will tell you plainly what we can and cannot supply.
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 order | Handheld XRF spectrometer (PMI) |
| Outer diameter | OD vs standard / drawing | Caliper |
| Inner diameter | ID & hole fit | Caliper |
| Thickness | Gauge vs standard | Caliper |
| Hardness | Material condition after stamping | Rockwell hardness tester |
| Quantity | Count vs order | Electronic scale |
| Surface / finish | Burrs, marks, finish | Visual inspection |
Tell us the documents your supply chain requires — a PMI reading or a dimensional report — and we will confirm scope and format with your quote. We cannot issue EN 10204 3.1 mill certificates.
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)?
No. Our coil suppliers do not pass on the steel mill’s certificate, so we cannot issue an EN 10204 3.1 mill test certificate. We verify the grade with our own handheld XRF spectrometer (PMI) and can include the reading with your order. If your purchase order requires a 3.1, please check with your quality team before ordering whether a PMI reading meets the requirement.
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 JH21-series 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 make sure the material is full-spec stainless?
We stamp to full thickness from stainless coil — no under-gauge, no recycled substitution. Grade is checked with our own handheld XRF spectrometer (PMI). We supply only 304 (A2), 316 (A4) and 316L (A4L) in one finish, tumble-polished in sawdust — no plating or coating that could hide off-grade base material.
What quality documentation can I request with an order?
Available on request: a PMI (XRF) grade reading from our handheld spectrometer and a dimensional inspection report. We cannot issue EN 10204 3.1 mill certificates. Tell us what your supply chain or goods-in team needs and we will confirm it with your quote.
Tell us what you need.
Send specs or a drawing and we will come back with pricing, lead time and material options. No account needed.
- ✓ 304 / 316 / 316L, DIN & ASME or custom
- ✓ Replies from our sales team, usually within one business day
- ✓ Samples on request, courier freight paid by the buyer