Home » DIN 128B Lock Washer Spring – 70# Steel Black

DIN 128B Lock Washer Spring – 70# Steel Black

DIN 128B Wavy Spring Lock Washer — 70# Spring Steel, Black Oxide

FULLERKREG DIN 128B wavy spring lock washers are manufactured to DIN 128 Type B standard in 70# high-carbon spring steel (Grade 70, per GB/T 699) with a black oxide surface treatment. DIN 128 Type B features a wavy (corrugated) profile with multiple waves around the ring circumference, generating distributed axial spring force with multi-point contact. The 70# spring steel achieves 40–50 HRC hardness after quench and temper. Black oxide is the preferred surface treatment for high-hardness spring steel — it produces a uniform Fe₃O₄ conversion coating with no hydrogen introduction, eliminating the embrittlement risk associated with electroplating at this hardness level.

Product Highlights

  • Standard: DIN 128 Type B (Wavy Spring Lock Washer)
  • Material: 70# Spring Steel (Grade 70, GB/T 699)
  • Surface Treatment: Black Oxide (Chemical Blackening / Fe₃O₄)
  • Appearance: Uniform matte black, non-reflective finish
  • Hardness: 40–50 HRC (392–513 HV) after quench & temper
  • Size Range: M2 – M36
  • Profile: Type B — Wavy / corrugated (multiple waves)
  • No hydrogen embrittlement risk — safe for high-hardness spring steel
  • RoHS & REACH Compliant

Dimensional Specifications — DIN 128 Type B (Wavy), 70# Steel Black

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

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 B. s = material thickness; b = ring width; h = free height (wavy profile height). Black oxide coating 1–3 um — negligible dimensional impact.

Material Properties — 70# Spring Steel (GB/T 699)

Property Value
Material Grade 70# Spring Steel (Grade 70)
GB Standard GB/T 699, GB/T 4354
C Content 0.67 – 0.75%
Mn Content 0.50 – 0.80%
Heat Treatment Quench & Temper
Hardness 40 – 50 HRC (392 – 513 HV)
Tensile Strength 1275 MPa min.
Surface Treatment Black Oxide (Chemical Blackening / Fe₃O₄)
Coating Thickness 1 – 3 um (conversion coating, negligible dimensional impact)
Operating Temperature -40°C to +120°C
RoHS / REACH Compliant

Chemical Composition — 70# Spring Steel (GB/T 699)

Element C Mn Si P max S max Cr max Ni max
Content % 0.67–0.75 0.50–0.80 0.17–0.37 0.035 0.035 0.25 0.25

Note: 70# steel (GB/T 699) is distinct from 65Mn spring steel (GB/T 1222). 70# has higher carbon (0.67–0.75%) and lower manganese (0.50–0.80%).

Black Oxide vs. Zinc — Surface Treatment Comparison

Property Black Oxide Zinc (Mechanical)
Coating thickness 1–3 um 8–25 um
Corrosion resistance Basic — indoor / dry Good — light outdoor & humid
H2 embrittlement risk None None (mechanical process)
Appearance Matte black Bright silver-grey
Dimensional impact Negligible 8–25 um added
Best for Indoor, dry, precision assemblies Outdoor, humid, general industrial

Application Scenarios

  • Heavy machinery & industrial equipment — indoor or dry environments, high spring force
  • Automotive manufacturing — engine, chassis, and drivetrain assemblies in dry environments
  • Electrical enclosures & control panels — matte black finish, non-reflective, professional appearance
  • Precision mechanical assemblies — 1–3 um coating preserves dimensional tolerances
  • Soft material assemblies — wavy profile distributes load without sharp edge marking
  • Railway & transportation equipment — sheltered environments requiring high spring force
  • DIN-standard bolt assemblies — anti-loosening in indoor industrial applications

Product Photo Gallery

FULLERKREG DIN 128B Wavy Spring Lock Washer, 70# Spring Steel, Black Oxide:

[ 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 and hardness
  • 🌍 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, hardness reports, RoHS declarations available
  • ⚡ Fast lead times — standard sizes in stock, ready to ship

Frequently Asked Questions

Q: What is DIN 128 Type B?
A: DIN 128 Type B is a wavy (corrugated) spring lock washer with multiple waves around the ring circumference. It generates distributed axial spring force with multi-point contact, providing anti-loosening performance without sharp edges or surface marking.

Q: Why black oxide for 70# spring steel?
A: At 40–50 HRC, electroplating introduces hydrogen embrittlement risk. Black oxide is a chemical conversion coating (Fe₃O₄) applied without acid pickling or electrical current, eliminating this risk. It is the preferred finish for high-hardness spring steel in indoor/dry environments.

Q: Black oxide vs. zinc — which to choose?
A: Black oxide (1–3 um) is ideal for indoor, dry, or precision applications where minimal coating thickness is critical. Choose zinc plating (8–25 um) for outdoor or humid environments requiring better corrosion protection.

Q: What is 70# spring steel?
A: Grade 70 per GB/T 699, C 0.67–0.75%, achieving 40–50 HRC after quench and temper. Superior spring force and fatigue resistance vs. standard carbon steel. Distinct from 65Mn spring steel.

Q: Do you provide material test certificates?
A: Yes. Mill certificates, hardness reports, chemical composition reports, and RoHS declarations available upon request.

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