DIN 433 Small O.D. Flat Washer — Low Carbon Steel, Zinc CR3

FULLERKREG DIN 433 small outer diameter flat washers are manufactured to DIN 433 / ISO 1580 standards in low carbon steel with a Zinc CR3 (trivalent chromium) electroplated finish. Designed for use with pan head and cheese head screws where a reduced bearing surface is required, these washers deliver reliable clamping performance in precision assemblies, electronics, and light mechanical applications.

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Product Highlights

• Standard: DIN 433 (equivalent to ISO 7092)
• Material: Low Carbon Steel
• Surface Treatment: Zinc Electroplated, Trivalent Chromium Passivation (CR3 / Blue-White)
• Corrosion Resistance: ≥ 72 hours salt spray (neutral, NSS) per ISO 9227
• RoHS & REACH Compliant
• Size Range: M1.6 – M24
• Finish: Bright zinc, uniform coating, no hydrogen embrittlement risk at standard hardness

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Dimensional Specifications — DIN 433 Small O.D. Flat Washers (Steel, Zinc CR3)

All dimensions in millimeters (mm). Tolerances per DIN 433 / ISO 7092.

Nominal Size (d)	Inner Dia. d1 (min)	Inner Dia. d1 (max)	Outer Dia. d2 (max)	Thickness h (min)	Thickness h (max)
M1.6	1.7	1.84	3.5	0.25	0.35
M2	2.1	2.24	4.5	0.25	0.35
M2.5	2.6	2.74	5.0	0.35	0.45
M3	3.1	3.28	6.0	0.45	0.55
M3.5	3.6	3.78	7.0	0.45	0.55
M4	4.1	4.28	8.0	0.55	0.70
M5	5.1	5.28	9.0	0.55	0.70
M6	6.1	6.28	11.0	0.8	1.0
M8	8.1	8.28	15.0	1.1	1.4
M10	10.1	10.28	18.0	1.6	2.0
M12	12.1	12.28	20.0	1.6	2.0
M14	14.1	14.28	24.0	1.6	2.0
M16	16.1	16.28	28.0	1.6	2.0
M20	20.1	20.28	34.0	2.0	2.5
M24	24.1	24.28	39.0	2.5	3.0

* All dimensions conform to DIN 433 / ISO 7092. Please verify with your engineering team for critical applications.

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Material & Mechanical Properties

Property	Value
Material	Low Carbon Steel (C ≤ 0.20%)
Hardness (HV)	100 – 200 HV
Tensile Strength	≥ 300 MPa
Surface Treatment	Zinc Electroplating + CR3 Trivalent Chromium Passivation
Coating Thickness	5 – 12 μm (typical)
Salt Spray Resistance	≥ 72 hours (ISO 9227 NSS)
Operating Temperature	-40°C to +120°C
RoHS / REACH	Compliant — No hexavalent chromium (Cr6+)

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Chemical Composition — Low Carbon Steel

Element	C	Mn	P (max)	S (max)	Si
Content (%)	≤ 0.20	0.30 – 0.60	0.045	0.045	≤ 0.35

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Surface Treatment — Zinc CR3 Explained

CR3 (trivalent chromium) passivation is the modern, environmentally compliant alternative to traditional hexavalent chromium (CR6) coatings. FULLERKREG Zinc CR3 washers offer:

• ✅ RoHS & ELV compliant — no Cr6+ hazardous substances
• ✅ Blue-white bright appearance — clean, professional finish
• ✅ ≥ 72 hours neutral salt spray resistance (ISO 9227)
• ✅ Uniform coating — consistent thickness across all contact surfaces
• ✅ Suitable for indoor and light outdoor applications

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Application Scenarios

• Used with pan head screws (DIN 7985 / ISO 7045) and cheese head screws (DIN 84 / ISO 1207)
• Electronics enclosures, control panels, and PCB assemblies
• Light machinery, HVAC equipment, and appliance manufacturing
• Furniture hardware and precision instrument assembly
• Automotive interior components and trim assemblies

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Product Photo Gallery

Real product images — FULLERKREG DIN 433 Small O.D. Flat Washer, Zinc CR3 finish:

[ Photo 1 ]

[ Photo 2 ]

[ Photo 3 ]

[ Photo 4 ]

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Packaging & Supply

Size	Standard Pack (pcs)	Bulk Carton (pcs)	Weight per 1000 pcs (approx.)
M3	200	10,000	~0.18 kg
M4	200	5,000	~0.35 kg
M5	100	3,000	~0.55 kg
M6	100	2,000	~1.10 kg
M8	50	1,000	~2.80 kg
M10	50	500	~5.50 kg
M12	25	500	~7.20 kg

Custom packaging and labeling available for OEM / wholesale orders. Contact FULLERKREG for bulk pricing.

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Why Choose FULLERKREG?

• 🏭 Direct manufacturer — factory in China, no middlemen
• 📐 Strict DIN/ISO dimensional control — 100% inspection on critical dimensions
• 🌍 Global export experience — serving distributors in Europe, North America, Southeast Asia
• 📦 Flexible MOQ — small trial orders and large bulk shipments both welcome
• 📋 Full documentation — material certs, RoHS declarations, test reports available
• ⚡ Fast lead times — standard sizes in stock, ready to ship

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Frequently Asked Questions

Q: What is the difference between DIN 433 and DIN 125 washers?
A: DIN 433 has a smaller outer diameter than DIN 125, making it suitable for use with pan head and cheese head screws where the washer must fit within the head recess area. DIN 125 is the standard flat washer for general use.

Q: Is Zinc CR3 the same as galvanized?
A: No. Zinc CR3 refers to electroplated zinc with trivalent chromium passivation — a thin, precise coating (5–12 μm). Hot-dip galvanizing produces a much thicker coating (45–85 μm) and is used for heavy structural applications. CR3 is preferred for precision fasteners where dimensional tolerances are critical.

Q: Are these washers RoHS compliant?
A: Yes. FULLERKREG Zinc CR3 washers use trivalent chromium (Cr3+) passivation only — no hexavalent chromium (Cr6+). Full RoHS and REACH compliance documentation is available upon request.

Q: Can I order mixed sizes?
A: Yes. FULLERKREG supports mixed-size wholesale orders. Please contact us with your size breakdown and quantities for a custom quotation.

Q: Do you provide material test certificates?
A: Yes. Mill certificates, dimensional inspection reports, and surface treatment test reports are available for all orders.

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FULLERKREG Fasteners — Precision DIN Standard Fasteners, Direct from Manufacturer.
For wholesale inquiries, technical questions, or custom orders, please contact our sales team.