Home » DIN 137B Spring Washer (Crinkled) – 65Mn Steel Zinc CR3

DIN 137B Spring Washer (Crinkled) – 65Mn Steel Zinc CR3

DIN 137B Crinkled Spring Washer — 65Mn Spring Steel, Zinc Plated CR3

FULLERKREG DIN 137B crinkled spring washers are manufactured to DIN 137 Type B standard in 65Mn high-manganese spring steel (per GB/T 1222) with zinc electroplating and trivalent chromium (CR3) passivation. DIN 137 Type B is a crinkled (wavy) spring washer featuring multiple corrugations around the ring circumference, providing distributed multi-point axial spring force with a larger outer diameter than DIN 128B. 65Mn spring steel achieves 430–510 HV hardness after quench and temper, delivering high spring force and excellent fatigue resistance. The zinc CR3 finish provides enhanced corrosion resistance (≥72h salt spray) with full RoHS compliance — no hexavalent chromium.

Note on hydrogen embrittlement: At 430–510 HV, electroplating introduces hydrogen embrittlement risk during acid pickling. FULLERKREG applies a controlled pre-treatment and mandatory post-plate baking process (per ISO 9587 / GB/T 13912) to drive off absorbed hydrogen, ensuring spring performance is maintained.

Product Highlights

  • Standard: DIN 137 Type B (Crinkled / Wavy Spring Washer)
  • Material: 65Mn Spring Steel (GB/T 1222)
  • Surface Treatment: Zinc Electroplating + CR3 Trivalent Chromium Passivation
  • Corrosion Resistance: ≥72h neutral salt spray (NSS) per ISO 9227
  • Hardness: 430–510 HV (approx. 44–50 HRC) after quench & temper
  • Size Range: M3 – M36
  • Profile: Type B — Crinkled / Wavy (multiple corrugations, larger OD than DIN 128B)
  • RoHS Compliant — CR3 trivalent chromium, no hexavalent chromium (Cr6+)
  • Post-plate baking — hydrogen embrittlement relief per ISO 9587

Dimensional Specifications — DIN 137 Type B (Crinkled), 65Mn Steel Zinc CR3

All dimensions in millimeters (mm). Per DIN 137 Type B.

Nominal Size For Bolt d1 min d2 max h min h max s (thickness)
3 M3 3.2 7.5 0.8 1.2 0.5
4 M4 4.3 9.5 1.0 1.4 0.6
5 M5 5.3 11.5 1.2 1.7 0.8
6 M6 6.4 14.0 1.5 2.1 1.0
8 M8 8.4 18.0 2.0 2.8 1.2
10 M10 10.5 22.0 2.5 3.5 1.5
12 M12 13.0 26.0 3.0 4.2 1.8
14 M14 15.0 30.0 3.5 4.9 2.0
16 M16 17.0 34.0 4.0 5.6 2.5
20 M20 21.0 42.0 5.0 7.0 3.0
24 M24 25.0 50.0 6.0 8.4 3.5
30 M30 31.0 62.0 7.5 10.5 4.0
36 M36 37.0 74.0 9.0 12.6 5.0

All dimensions in mm per DIN 137 Type B. s = material thickness; h = free height (crinkled profile height).

Material Properties — 65Mn Spring Steel (GB/T 1222)

Property Value
Material Grade 65Mn Spring Steel
GB Standard GB/T 1222, GB/T 4354
Heat Treatment Quench & Temper
Hardness 430–510 HV (approx. 44–50 HRC)
Tensile Strength 1275 MPa min. (after HT)
Surface Treatment Zinc Electroplating + CR3 Passivation
Salt Spray Resistance ≥72h NSS per ISO 9227
H2 Embrittlement Relief Post-plate baking per ISO 9587 / GB/T 13912
Operating Temperature -40°C to +120°C
RoHS / REACH Compliant — CR3, no Cr6+

Chemical Composition — 65Mn Spring Steel (GB/T 1222)

Element C Mn Si P max S max Cr max Ni max
Content % 0.62–0.70 0.90–1.20 0.17–0.37 0.035 0.035 0.25 0.25

65Mn has higher manganese (0.90–1.20%) than 70# steel (0.50–0.80%), improving hardenability and toughness for larger cross-sections.

Zinc CR3 vs. Black Oxide — Surface Treatment Comparison

Property Zinc CR3 (this product) Black Oxide
Coating type Electroplated zinc + CR3 passivation Chemical conversion (Fe₃O₄)
Coating thickness 5–12 um 1–3 um
Salt spray resistance ≥72h NSS Basic — indoor / dry only
Corrosion resistance Good — outdoor & humid environments Basic — indoor / dry
Appearance Bright silver with slight blue tint Matte black
RoHS compliant Yes — CR3, no Cr6+ Yes
Best for Outdoor, humid, general industrial Indoor, dry, precision assemblies

Application Scenarios

  • Heavy machinery & industrial equipment — high spring force with outdoor corrosion protection
  • Automotive manufacturing — chassis, underbody, and engine assemblies exposed to moisture
  • Construction & steel structures — sheltered outdoor environments
  • Agricultural & mining equipment — high-vibration, humid conditions
  • Railway & transportation equipment — vibration resistance with corrosion protection
  • Soft material assemblies — crinkled profile distributes load without sharp edge marking
  • General bolted assemblies — where RoHS-compliant zinc finish is required

Product Photo Gallery

FULLERKREG DIN 137B Crinkled Spring Washer, 65Mn Spring Steel, Zinc CR3:

[ 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, salt spray reports, RoHS declarations available
  • ⚡ Fast lead times — standard sizes in stock, ready to ship

Frequently Asked Questions

Q: What is CR3 passivation?
A: CR3 refers to trivalent chromium passivation applied over the zinc electroplating. It provides enhanced corrosion protection and a bright appearance without using hexavalent chromium (Cr6+), making it fully RoHS compliant. CR3 passivation achieves ≥72h neutral salt spray resistance per ISO 9227.

Q: How is hydrogen embrittlement managed for 65Mn spring steel?
A: At 430–510 HV, electroplating introduces hydrogen during acid pickling. FULLERKREG applies mandatory post-plate baking (typically 190–220°C for 4–8 hours per ISO 9587) to drive off absorbed hydrogen before the zinc coating fully seals. This process restores spring properties and eliminates embrittlement risk.

Q: What is DIN 137 Type B?
A: DIN 137 Type B is a crinkled (wavy) spring washer with multiple corrugations around the ring circumference. It generates distributed multi-point axial spring force with a larger outer diameter than DIN 128B, providing higher load capacity and better load distribution without sharp edges.

Q: What is 65Mn spring steel?
A: 65Mn (GB/T 1222) is a high-manganese spring steel with C 0.62–0.70% and Mn 0.90–1.20%. After quench and temper, it achieves 430–510 HV, providing excellent spring force and fatigue resistance.

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

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