DIN 433 Small O.D. Flat Washer — Low Carbon Steel, Black Oxide

FULLERKREG DIN 433 small outer diameter flat washers are manufactured to DIN 433 / ISO 7092 standards in low carbon steel with a black oxide surface treatment. The deep matte-black finish provides a professional aesthetic combined with basic corrosion inhibition, making these washers ideal for precision assemblies, optical equipment, electronics, and applications where a non-reflective, clean appearance is required.

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Product Highlights

• Standard: DIN 433 (equivalent to ISO 7092)
• Material: Low Carbon Steel
• Surface Treatment: Black Oxide (Blackening / Gun-Black)
• Appearance: Uniform matte black, non-reflective finish
• Size Range: M1.6 – M24
• RoHS & REACH Compliant
• Recommended Use: With pan head and cheese head screws (DIN 7985, DIN 84)

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

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	Black Oxide (Chemical Blackening)
Coating Thickness	1 – 3 μm (conversion coating, no dimensional impact)
Corrosion Resistance	Basic — recommended with oil or wax sealant for enhanced protection
Operating Temperature	-40°C to +120°C
RoHS / REACH	Compliant

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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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Black Oxide Surface Treatment — Explained

Black oxide (also known as blackening or gun-black) is a chemical conversion coating applied to steel through an alkaline oxidizing bath. It produces a uniform, matte-black magnetite (Fe₃O₄) layer on the surface. Key characteristics:

• ✅ Non-reflective matte black finish — ideal for optical, electronic, and aesthetic applications
• ✅ Negligible dimensional change — coating thickness only 1–3 μm, no impact on tolerances
• ✅ Reduced light reflection — preferred in camera, sensor, and precision instrument assemblies
• ✅ RoHS compliant — no heavy metals or hazardous substances
• ⚠️ Moderate corrosion resistance — apply oil or wax sealant for outdoor or humid environments
• ✅ Good adhesion base — compatible with supplementary oil, lacquer, or wax coatings

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Application Scenarios

• Used with pan head screws (DIN 7985 / ISO 7045) and cheese head screws (DIN 84 / ISO 1207)
• Optical instruments, camera housings, and sensor assemblies requiring non-reflective hardware
• Electronics enclosures, control panels, and PCB assemblies
• Precision mechanical assemblies where appearance and dimensional accuracy are critical
• Furniture hardware, decorative fixtures, and interior design applications
• Automotive interior trim and dashboard assemblies
• Industrial machinery with aesthetic or low-visibility hardware requirements

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Product Photo Gallery

Real product images — FULLERKREG DIN 433 Small O.D. Flat Washer, Black Oxide 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 Black and DIN 125 Black washers?
A: DIN 433 has a smaller outer diameter than DIN 125, designed specifically for use with pan head and cheese head screws where the washer must fit within the head recess. DIN 125 is the standard flat washer for general-purpose use.

Q: How durable is the black oxide finish?
A: Black oxide provides basic corrosion inhibition. For enhanced protection in humid or outdoor environments, we recommend applying a light oil or wax sealant after installation. The finish is highly durable in dry indoor conditions.

Q: Does black oxide affect the dimensions or tolerances?
A: No. Black oxide is a conversion coating with a thickness of only 1–3 μm, which has no measurable impact on dimensional tolerances. This makes it ideal for precision assemblies.

Q: Are these washers RoHS compliant?
A: Yes. FULLERKREG black oxide washers are fully RoHS and REACH compliant. No hexavalent chromium or other restricted substances are used in the surface treatment process.

Q: Can I order mixed sizes in one shipment?
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 upon request.

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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.