DIN 128A Saddle Spring Washers – High Strength Anti-Loosening Washers for Bolted Connections

DIN 128A Saddle Spring Washers: Reliable Elastic Locking Solution for Bolted Assemblies

What Are DIN 128A Saddle Spring Washers?

DIN 128A saddle spring washers are curved spring washers designed to provide elastic preload, vibration resistance, and fastening stability in bolted connections.

The washer features a saddle-shaped curved profile, allowing it to compress during tightening and generate elastic restoring force. This stored energy helps maintain bolt tension and reduces the risk of fastener loosening during operation.

DIN128 spring washers are widely used in mechanical assemblies where vibration, impact loads, or dynamic forces may cause bolts and nuts to loosen.

Typical industries using DIN128A washers include:

• mechanical manufacturing

• automotive industry

• aerospace engineering

• industrial equipment

• heavy machinery

According to the DIN 128 standard, saddle spring washers are classified into:

• Type A (DIN128A) – standard curved      spring washer

• Type B (DIN128B) – modified      structure for different installation requirements

These washers are commonly used for bolts with strength class 8.8 or lower.

Structure and Working Principle of DIN128A Saddle Spring Washers

The DIN128A saddle spring washer features a curved elastic structure, consisting of:

• inner curved surface

• outer curved surface

• intermediate saddle-shaped profile

When the bolt is tightened, the washer compresses and stores elastic potential energy.

During operation:

1. External loads or vibration may reduce bolt tension.

2. The compressed washer attempts to return to its original shape.

3. This elastic recovery force helps maintain the bolt preload.

4. Increased friction between contact surfaces reduces loosening.

This design provides basic anti-loosening capability and vibration damping, improving the stability of the fastener assembly.

However, in extremely high vibration environments, additional locking solutions may be required.

Key Features of DIN128A Saddle Spring Washers

Stable Elastic Spring Force

The saddle-shaped structure provides a stable and consistent spring force, helping maintain clamping pressure in bolted joints.

Excellent Fatigue Resistance

DIN128A washers are manufactured from high-strength spring steel or stainless steel, providing excellent fatigue resistance under repeated loading cycles.

Impact and Vibration Damping

The elastic deformation of the washer helps absorb mechanical shock and vibration, protecting fastener assemblies from loosening or damage.

Long Service Life

Due to their high fatigue strength and durable materials, DIN128A washers offer long-term reliability in mechanical applications.

Simple Installation

DIN128A spring washers can be easily installed with standard bolts and nuts without requiring special tools or installation procedures.

Materials for DIN128A Saddle Spring Washers

DIN128A washers are available in several materials depending on application requirements.

Carbon Spring Steel

Common grades include:

• 65Mn spring steel

• 70# carbon steel

These materials provide high strength, excellent fatigue resistance, and strong elastic recovery.

Stainless Steel

Common stainless steel options include:

• SUS304 (A2)

• SUS316 (A4)

Stainless steel washers provide superior corrosion resistance, making them suitable for humid or chemically aggressive environments.

Hardness Grades

DIN128A washers are available in multiple hardness levels, including:

• 100HV

• 140HV

• 200HV

• 300HV

Different hardness grades are selected according to the strength requirements of the bolted joint.

Surface Treatments

To improve corrosion resistance and durability, DIN128A washers may undergo various surface treatments.

Common finishes include:

• blue-white zinc plating

• yellow zinc plating

• hot-dip galvanizing

• environmentally friendly zinc plating

• Dacromet coating

These coatings improve corrosion resistance and extend service life in demanding environments.

Corrosion Resistance Performance

Surface-treated washers can achieve various neutral salt spray test performance levels, such as:

• 72 hours

• 96 hours

• 120 hours

• 300 hours

• 360 hours

• 720 hours

This ensures reliable performance in outdoor or corrosive environments.

Industrial Applications of DIN128A Saddle Spring Washers

DIN128A washers are widely used across multiple industries where secure and stable bolted connections are required.

Mechanical Equipment Manufacturing

DIN128A washers are commonly used in mechanical assemblies including:

• industrial machinery

• production equipment

• structural fasteners

• machine components

They help maintain stable bolt preload and reduce vibration effects.

Automotive Industry

In vehicle manufacturing, saddle spring washers are used in:

• engine components

• chassis assemblies

• suspension systems

• mechanical fastening structures

They help maintain fastening reliability under continuous vibration.

Aerospace Engineering

In aerospace applications, fasteners must withstand extreme conditions and repeated loads.

DIN128A washers can be used in aircraft structures, aerospace equipment, and mechanical fastening systems where fatigue resistance is essential.

Industrial Equipment and Heavy Machinery

Heavy-duty equipment such as:

• construction machinery

• mining equipment

• manufacturing machines

often rely on DIN128A washers to provide stable fastening performance under mechanical stress.

Selection Guidelines for DIN128A Saddle Spring Washers

When selecting DIN128A washers, engineers should consider the following factors.

Working Environment

Choose stainless steel washers for corrosive environments such as marine or chemical conditions.

Load and Pressure Requirements

Select washers with appropriate hardness and strength based on the load conditions of the fastener assembly.

Bolt Size Compatibility

Ensure the washer size matches the bolt or nut dimension to achieve proper load distribution.

Quality Requirements

High-quality washers manufactured according to DIN128A standards provide more reliable performance and longer service life.

Advantages of DIN128A Saddle Spring Washers

DIN128A washers provide several benefits for mechanical fastening systems:

• maintain bolt preload

• reduce loosening caused by vibration

• improve fatigue resistance

• absorb shock and impact loads

• extend service life of fastener assemblies

These advantages make them a widely used spring washer solution in industrial fastening applications.

 If you are looking for high-quality DIN128 spring washers, lock washers, or custom fastener solutions, our engineering team can provide professional technical support.

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