Stainless Steel Serrated Washer - Grade 202, 304, 316, A2, A2-70

A serrated washer is a type of lock washer designed with ridges or serrations either on one or both surfaces. These serrations bite into the mating surfaces (bolt head/nut and material surface) to prevent loosening due to vibration or torque.

Technical Specifications – Serrated Washers

Here is a technical specification table for Serrated Washers (general dimensions based on DIN 6798 standard):

Nominal Size (M)	Inner Diameter (d₁) mm	Outer Diameter (d₂) mm	Thickness (t)** mm	Type A (Internal Serration)	Type B** (External Serration)
M2	2.2	4.5	0.3	✓	✓
M3	3.2	6.2	0.4	✓	✓
M4	4.3	7.6	0.5	✓	✓
M5	5.3	9.2	0.6	✓	✓
M6	6.4	11.0	0.7	✓	✓
M8	8.4	13.6	0.9	✓	✓
M10	10.5	17.0	1.0	✓	✓
M12	13.0	20.4	1.2	✓	✓
M16	17.0	26.0	1.6	✓	✓

Spring Steel offers the highest clamping force due to elasticity.
SS316 is preferred in corrosive environments and high-humidity areas.
Brass and Bronze are ideal for electrical conductivity and non-magnetic applications.
Aluminium is suitable for weight-sensitive assemblies
Enhanced resistance to vibration and loosening
Maintains consistent torque in bolted joints
Distributes load more evenly than plain washers
Reduces the need for re-tightening in dynamic assemblies
Stainless Steel (SS304, SS316)
Spring Steel
Carbon Steel (with Zinc Plating, Black Oxide, etc.)

Material Comparison Chart – Serrated Washers

Material	Grade/Type	Corrosion Resistance	Mechanical Strength	Temperature Resistance	Surface Finish Options	Common Applications
Carbon Steel	C45 / EN8	Low	High	Moderate	Zinc Plated, Black Oxide	General engineering, machinery
Spring Steel	65Mn / EN42J	Low to Moderate	Very High	Moderate	Phosphated, Blackened	Dynamic joints, automotive, vibration zones
Stainless Steel	SS304	High	Moderate to High	High	Natural (Bright), Passivated	Marine, food industry, outdoor equipment
Stainless Steel	SS316	Very High	High	Very High	Natural (Bright), Passivated	Chemical processing, pharma, coastal use
Brass	CuZn37	Moderate	Low to Moderate	Low	Natural, Polished	Electrical terminals, aesthetic applications
Aluminium	5052 / 6061	Moderate to High	Low to Moderate	High	Anodized	Lightweight assemblies, electronics
Phosphor Bronze	PB1 / PB2	High	Moderate	Moderate	Natural, Tinned	Electrical, marine, anti-sparking environments

Serrated washers, otherwise referred to as shake-proof or toothed lock washers, serve the purpose of preventing bolted joints from loosening as a result of vibration or rotation. Their function is achieved by establishing a high-friction interface between the washer, fastener, and mating surface, ultimately securing the connection in place.

Material

Stainless Steel (304/316)

Inner Diameter (d₁) mm

2.2 - 17.0

Outer Diameter (d₂) mm

4.5 - 26.0

Thickness (t)** mm

0.3 - 1.6

Anti-vibration

The washer's serrations serve to bite into the material and resist any movement, effectively preventing loosening due to vibrations.

Increased friction

By adding serrations to the washer, it increases the amount of friction between the washer and mating surfaces. This ultimately impedes rotation and prevents loosening.

Secure fastening

Serrated washers are essential in maintaining tension within a bolted joint, as they play a crucial role in keeping the connection tight and secure.

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