Home » DIN 128A Lock Washer Spring – A4 Stainless

DIN 128A Lock Washer Spring – A4 Stainless

DIN 128A Curved Spring Lock Washer — A4 Marine Stainless Steel (SUS316), Whitened & Passivated

FULLERKREG DIN 128A curved spring lock washers are manufactured to DIN 128 Type A standard in A4 marine stainless steel (SUS316 / 1.4401 / 06Cr17Ni12Mo2) with a whitened and passivated surface finish. A4 stainless steel contains 2–3% molybdenum, providing superior resistance to chloride corrosion, seawater, and acidic environments compared to A2 (SUS304). DIN 128 Type A is a curved (single-coil) spring washer that generates axial spring force through its curved profile, providing anti-loosening performance without marking or damaging bearing surfaces.

Product Highlights

  • Standard: DIN 128 Type A (Curved Spring Lock Washer)
  • Material: A4 Marine Stainless Steel (SUS316 / 1.4401 / 06Cr17Ni12Mo2)
  • Surface Treatment: Whitened & Passivated
  • Size Range: M2 – M36
  • Profile: Type A — Curved (single-coil, not helical split)
  • Molybdenum content: 2–3% — superior chloride & seawater resistance vs. A2
  • Non-magnetic, non-sparking
  • RoHS & REACH Compliant

Dimensional Specifications — DIN 128 Type A (Curved), A4 Stainless

All dimensions in millimeters (mm). Per DIN 128 Type A.

Nominal Size For Bolt d1 min d2 max h min h max s (thickness) b (width)
2 M2 2.1 4.4 0.70 1.10 0.6 0.9
2.3 M2.3 2.4 4.9 0.90 1.10 0.6 0.9
2.5 M2.5 2.6 5.1 0.90 1.10 0.6 1.0
2.6 M2.6 2.7 5.2 0.90 1.10 0.6 1.0
3 M3 3.1 6.2 1.10 1.30 0.7 1.3
3.5 M3.5 3.6 6.7 1.20 1.30 0.7 1.3
4 M4 4.1 7.6 1.20 1.40 0.8 1.5
5 M5 5.1 9.2 1.50 1.70 1.0 1.8
6 M6 6.1 11.8 2.00 2.20 1.3 2.5
8 M8 8.1 14.8 2.45 2.75 1.6 3.0
10 M10 10.2 18.1 2.85 3.35 1.8 3.5
12 M12 12.2 21.1 3.35 3.65 2.1 4.0
14 M14 14.2 24.1 3.90 4.30 2.4 4.5
16 M16 16.2 27.4 4.50 5.10 2.8 5.0
18 M18 18.2 26.4 4.50 5.10 2.8 5.0
20 M20 20.2 33.6 5.10 5.90 3.2 6.0
22 M22 22.5 35.9 5.10 5.90 3.2 6.0
24 M24 24.5 40.0 6.50 7.50 4.0 7.0
27 M27 27.5 43.0 6.50 7.50 4.0 7.0
30 M30 30.5 48.2 9.50 10.50 5.0 8.0
36 M36 36.5 58.2 10.30 11.30 6.0 10.0

All dimensions in mm per DIN 128 Type A. s = material thickness; b = ring width; h = free height. Same dimensions as A2 grade — material and corrosion resistance differ.

Material & Mechanical Properties — A4 Marine Stainless Steel (SUS316)

Property Value
Material Grade A4 / SUS316 / 1.4401 / 06Cr17Ni12Mo2
Cr Content 16.0 – 18.0%
Ni Content 10.0 – 14.0%
Mo Content 2.0 – 3.0% — key differentiator vs. A2
Surface Treatment Whitened & Passivated
Magnetic Non-magnetic (austenitic)
Operating Temperature -196°C to +300°C
Corrosion Resistance Excellent — seawater, chlorides, acids, marine environments
RoHS / REACH Compliant

A4 vs. A2 Stainless Steel — Key Differences

Property A4 (SUS316) — This Product A2 (SUS304)
Molybdenum (Mo) 2.0 – 3.0% None
Chloride resistance Superior — marine grade Good — general use
Seawater resistance Excellent Limited
Acid resistance Better (Mo addition) Standard
Typical use Marine, offshore, coastal, chemical General outdoor, food, fresh water
Cost Higher Standard

Application Scenarios

  • Marine & offshore structures — seawater splash zones, boat fittings, dock hardware
  • Coastal construction — salt air environments, bridges, coastal infrastructure
  • Chemical processing equipment — resistance to acids and chloride-containing media
  • Food & beverage processing — hygienic, easy to clean, non-toxic
  • Pharmaceutical & medical equipment — non-magnetic, corrosion-free
  • Swimming pools & water treatment — chlorinated water resistance
  • Cheese head & pan head screw assemblies — DIN 84 / DIN 7985 applications

Product Photo Gallery

FULLERKREG DIN 128A Curved Spring Lock Washer, A4 Marine Stainless Steel:

[ Photo 1 ] [ Photo 2 ] [ Photo 3 ] [ Photo 4 ]

Why Choose FULLERKREG?

  • 🏭 Direct manufacturer — factory in China, no middlemen
  • 📐 Strict DIN 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

Frequently Asked Questions

Q: Why choose A4 over A2 for spring lock washers?
A: A4 (SUS316) contains 2-3% molybdenum which significantly improves resistance to chloride pitting and crevice corrosion. In marine, coastal, or chloride-rich environments where A2 (SUS304) may suffer pitting corrosion, A4 is the correct choice.

Q: What is DIN 128 Type A?
A: DIN 128 Type A is a curved spring lock washer. The washer is formed into a single curved arc. When compressed under bolt load, it acts as a spring to maintain axial clamping force and resist loosening. Unlike DIN 127B (helical split), it has no sharp edges and does not mark bearing surfaces.

Q: Which screw types is DIN 128A designed for?
A: DIN 128A is specifically designed for cheese head screws (DIN 84 / ISO 1207) and pan head screws (DIN 7985 / ISO 7045).

Q: Do you provide material test certificates?
A: Yes. Mill certificates, chemical composition reports, and dimensional inspection reports are available upon request.

FULLERKREG Fasteners — Precision DIN Standard Fasteners, Direct from Manufacturer.
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