Ribbed Safety Lock Washer VS Series - Heavy Duty | A4 Stainless Steel (SUS316)

FULLERKREG Ribbed Safety Lock Washers VS Series (Heavy Duty) in A4 Stainless Steel (SUS316 / 1.4401) conform to DIN 9250 Type VS. Combining the maximum spring force of the VS Heavy Duty profile with the superior corrosion resistance of A4 stainless steel (molybdenum-alloyed), these washers are the premium choice for high-load bolted joints in marine, chemical, offshore, and coastal environments where both vibration resistance and corrosion protection are critical.

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Product Overview

• Standard: DIN 9250 Type VS (Schnorr-type ribbed safety lock washer, Heavy Duty)
• Series: VS - Heavy Duty (increased wall thickness and cone height vs S Series)
• Material: A4 Stainless Steel (SUS316 / 1.4401)
• Surface Treatment: Passivated and Whitened
• Thread Range: M5 - M30
• Serration: Fine radial ribs on both top and bottom faces
• Function: Anti-loosening, maximum vibration resistance, high pre-load retention
• Also known as: Schnorr VS washer, heavy duty conical lock washer, heavy duty Belleville lock washer

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Dimensional Data - DIN 9250 Type VS Heavy Duty (A4 Stainless Steel)

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

Thread Size	Inner Dia. d1	Outer Dia. d2	Thickness s	Height h Min	Height h Max
M5	5.3	9	1	1.2	1.4
M6	6.4	10	1	1.4	1.6
M7	7.4	12	1.2	1.7	2.0
M8	8.4	13	1.2	1.7	2.0
M10	10.5	16	1.5	2.0	2.4
M12	13	18	1.5	2.1	2.4
M14	15	22	2.0	2.7	3.1
M16	17	24	2.0	2.6	3.0
M18	19	27	2.5	3.2	3.7
M20	21	30	2.5	3.3	3.8
M22	23	33	2.5	3.4	3.9
M24	25.6	36	3.0	3.9	4.5
M27	28.6	39	3.0	4.0	4.6
M30	31.6	45	3.5	4.5	5.2

Note: All A4 Stainless Steel fasteners may exhibit slight magnetic properties due to cold forming. Refer to ISO 3506-2 Annex I. For sizes M33 and above, contact FULLERKREG for availability.

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VS Series vs S Series - Key Differences

Property	VS Series - Heavy Duty (This Page)	S Series - Regular Duty
Wall Thickness s	Thicker (1.0-3.5 mm)	Standard (0.3-2.0 mm)
Cone Height h	Greater	Standard
Spring Force	High	Medium
Pre-load Retention	Maximum	Good
Thread Range	M5 - M30	M1.6 - M30
Best For	Heavy machinery, high-torque joints, severe vibration	General industrial, standard bolt loads

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A4 vs A2 - Which Grade Should You Choose?

Property	A4 (SUS316) - This Page	A2 (SUS304)
Base Alloy	16% Cr, 10% Ni, 2% Mo	18% Cr, 8% Ni
Molybdenum Content	2-3% - key for chloride resistance	None
Corrosion Resistance	Excellent - marine, chemical, coastal	Good - indoor / mild outdoor
Chloride Resistance	Superior (pitting and crevice corrosion)	Limited
Recommended Environment	Marine, food processing, chemical plant	General industrial
Price	Premium	Standard

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How It Works - Schnorr Ribbed Safety Lock Washer

The VS Series washer operates on two simultaneous locking mechanisms:

• 🔩 Conical spring action - the increased cone height stores greater elastic energy under bolt load. As the bolt tends to loosen, the washer pushes back with higher force, maintaining clamp load even under severe vibration and thermal cycling.
• 🔒 Radial rib grip - fine ribs on both faces bite into the bolt head/nut bearing surface and the joint surface, creating strong mechanical resistance to rotation in both directions.

Washers can be stacked in the same direction to multiply spring force, or back-to-back to increase deflection range while maintaining locking grip.

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Standard and Compliance

DIN 9250 specifies ribbed safety lock washers (Schnorr-type) in two series:

• Type S - Regular Duty (standard dimensions)
• Type VS - Heavy Duty (increased thickness and cone height, this page)

DIN 9250 is functionally cross-referenced with NFE 25-511 (French standard) and the Schnorr original specification. FULLERKREG washers are manufactured to full DIN 9250 Type VS dimensional compliance. Material certification (EN 10204 3.1) available on request for bulk orders.

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Material and Surface Specification

Property	Specification
Material Grade	A4 Stainless Steel (SUS316 / 1.4401)
Surface Treatment	Passivated and Whitened
Corrosion Resistance	Excellent - suitable for marine, coastal, and chemical environments
Magnetic Properties	Slightly magnetic after cold forming (per ISO 3506-2 Annex I)
Temperature Range	-196 to +300 degrees C (continuous service)
RoHS Compliant	Yes

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Key Features and Technical Advantages

• 🔩 Heavy Duty spring force - thicker wall and greater cone height deliver maximum pre-load retention
• 🔒 Dual locking mechanism - conical spring pre-load + radial rib grip on both faces
• 🌊 Superior corrosion resistance - A4/SUS316 with molybdenum for marine and chemical environments
• 🔄 Reusable - washers retain locking strength if not deformed or damaged during removal
• ⚡ Electrical conductivity - ribs penetrate oxide layers for reliable grounding and bonding
• 🔀 Stackable - same-direction for higher force; back-to-back for greater deflection
• 🏭 Bulk supply ready - available in bags, boxes, and custom packaging for production lines

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Typical Applications

• Marine and offshore structural connections, deck fittings, and hull assemblies
• Coastal and waterfront heavy construction
• Power generation in marine environments - offshore wind turbines, tidal energy
• Chemical plant high-load pipework flanges and pressure vessels
• Food processing and pharmaceutical heavy machinery
• Swimming pool and water treatment structural bolting
• Desalination plant equipment
• High-torque bolted joints in salt-spray zones

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Product Gallery

Ribbed Safety Lock Washer VS Series Heavy Duty - A4 Stainless Steel

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Why Choose FULLERKREG?

🏆 Standard Compliance - Full DIN 9250 Type VS dimensional conformance, with NFE 25-511 cross-reference support
🔬 Material Traceability - EN 10204 3.1 mill certificates available for A4 grade
📦 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, stacking calculations, and custom specifications
⚙️ Broad Range - VS Series and S Series available in A2, A4 stainless steel and 65Mn spring steel grades