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Ribbed Safety Lock Washer S Series Regular Duty 65Mn Black

Ribbed Safety Lock Washer S Series - Regular Duty | 65Mn Spring Steel | Black Oxide

FULLERKREG Ribbed Safety Lock Washers S Series (Regular Duty) in 65Mn Spring Steel with Black Oxide surface treatment conform to DIN 9250 Type S. The high hardness (420-500 HV) of 65Mn spring steel delivers strong conical spring-back force and superior pre-load retention, while the black oxide finish provides a clean, professional appearance with basic corrosion protection for dry and indoor environments.

Product Overview

  • Standard: DIN 9250 Type S (Schnorr-type ribbed safety lock washer, Regular Duty)
  • Series: S - Regular Duty
  • Material: 65Mn Spring Steel
  • Surface Treatment: Black Oxide (Blackening)
  • Thread Range: M1.6 - M30
  • Serration: Fine radial ribs on both top and bottom faces
  • Function: Anti-loosening, vibration resistance, elastic pre-load retention
  • Also known as: Schnorr washer, conical spring washer, Belleville lock washer

Dimensional Data - DIN 9250 Type S Regular Duty (65Mn Black)

All dimensions in mm. Data per DIN 9250 Type S standard.

Thread Size Inner Dia. d1 Outer Dia. d2 Thickness s Height h Min Height h Max
M1.6 1.7 3.2 0.3 0.5 0.6
M2 2.2 4 0.35 0.5 0.6
M2.5 2.7 4.8 0.45 0.6 0.8
M3 3.2 5.5 0.45 0.8 0.9
M3.5 3.7 6 0.45 0.8 0.9
M4 4.3 7 0.5 0.9 1.0
M5 5.3 9 0.6 1.0 1.1
M6 6.4 10 0.7 1.1 1.2
M6.35 6.7 9.5 0.7 1.1 1.2
M7 7.4 12 0.7 1.2 1.3
M8 8.4 13 0.8 1.3 1.4
M10 10.5 16 1.0 1.5 1.6
M11 11.6 15.5 1.0 1.5 1.6
M12 13 18 1.1 1.6 1.7
M12.7 13.7 19 1.1 1.7 1.8
M14 15 22 1.2 1.9 2.0
M16 17 24 1.3 2.0 2.1
M18 19 27 1.5 2.2 2.3
M20 21 30 1.5 2.3 2.4
M22 23 33 1.5 2.4 2.5
M24 25.6 36 1.8 2.6 2.7
M25.4 27 38 2.0 2.7 2.8
M27 28.6 39 2.0 2.8 2.9
M30 31.6 45 2.0 3.1 3.2

Note: Black oxide finish provides minimal corrosion protection. For outdoor or humid environments, consider Zinc Cr3 or Zinc Yellow variants. For sizes M33 and above, contact FULLERKREG for availability.

Surface Treatment - Black Oxide Explained

Black Oxide (blackening / alkaline black finish) is a chemical conversion coating. Key characteristics:

  • ⬛ Appearance - uniform matte black finish; professional and aesthetically clean
  • 📐 Dimensional stability - coating 1-2 microns thick; negligible effect on dimensions
  • 🛡️ Corrosion resistance - basic protection for dry indoor use only
  • ⚡ Electrical conductivity - maintains good conductivity for grounding applications
  • ♻️ RoHS compliant - no hazardous substances

Material Grade Comparison - 65Mn vs Stainless Steel

Property 65Mn Black (This Page) A2 Stainless A4 Stainless
Hardness 420-500 HV ~200-300 HV ~200-300 HV
Spring-back Force High Medium Medium
Pre-load Retention Excellent Good Good
Corrosion Resistance Basic (dry indoor) Good Excellent
Appearance Matte black Silver/white Silver/white
RoHS Compliant Yes Yes Yes

Selection Guide - S Series vs VS Series

Series Duty Wall Thickness Cone Height Spring Force Best For
S (this page) Regular Duty Standard Standard Medium-High General industrial, standard bolt loads
VS Heavy Duty Thicker Higher High Heavy machinery, high pre-load, severe vibration

How It Works

The S Series washer operates on two simultaneous locking mechanisms:

  • 🔩 Conical spring action - cone profile stores elastic energy under bolt load, pushing back to maintain clamp force as the bolt tends to loosen.
  • 🔒 Radial rib grip - fine ribs on both faces bite into mating surfaces, creating mechanical resistance to rotation in both directions.

Stack in the same direction to multiply spring force, or back-to-back to increase deflection range.

Standard and Compliance

DIN 9250 Type S (Regular Duty) cross-referenced with NFE 25-511 and Schnorr original specification. FULLERKREG washers are manufactured to full DIN 9250 Type S dimensional compliance.

Material and Surface Specification

Property Specification
Material 65Mn Spring Steel
Hardness 420-500 HV
Surface Treatment Black Oxide (Blackening)
Coating Thickness 1-2 microns
Corrosion Resistance Basic - dry indoor environments only
Temperature Range -40 to +120 degrees C
RoHS Compliant Yes

Key Features

  • 🔩 High hardness 420-500 HV - superior spring-back force vs stainless steel
  • 🔒 Dual locking mechanism - conical spring + radial rib grip
  • ⬛ Matte black finish - professional appearance for visible assemblies
  • 📐 Dimensionally stable - 1-2 micron coating, no impact on fit
  • 🔄 Reusable - retains locking strength if undamaged
  • 🔀 Stackable - same-direction for higher force; back-to-back for deflection
  • 🏭 Bulk supply ready - bags, boxes, custom packaging available

Typical Applications

  • Precision instruments, optical equipment, and camera mounts
  • Electronics enclosures and PCB mounting hardware
  • Automotive interior and underhood assemblies (dry zones)
  • Industrial machinery in dry indoor environments
  • Furniture and architectural metalwork requiring black finish
  • Electrical cabinets and control panels (indoor)

Product Gallery

Ribbed Safety Lock Washer S Series Regular Duty - 65Mn Spring Steel / Black Oxide

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Why Choose FULLERKREG?

🏆 Standard Compliance - Full DIN 9250 Type S conformance, NFE 25-511 cross-reference support
🔬 Material Traceability - 65Mn spring steel mill certificates available on request
📦 Flexible MOQ - Small batch samples to full production quantities; custom packaging available
🌍 Global Shipping - Reliable export logistics to Europe, North America, Southeast Asia, and beyond
💬 Technical Support - Engineering team available for selection guidance and stacking calculations
⚙️ Broad Range - S and VS Series in A2, A4 stainless steel and 65Mn spring steel grades

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