SES N 3125 Metal Coated Steel Plates and Strips

Developed by Suzuki Motor Corporation as part of its standards for cast iron and iron-based materials, the “SES N 3125 Metal-coated steel sheets and strips” standard describes the requirements for coated steel sheets (typically zinc, aluminum, or alloy steel coatings) used in automotive applications.

Metal-coated steel sheets and strips (such as galvanized, galvanneal, or aluminized steels) are widely used in the automotive industry, primarily for corrosion protection, durability, and manufacturability.

Metal-clad steel sheets are steel sheets coated with a thin layer of metal, such as:

• Zinc: galvanized steel
• Zinc-iron alloy: galvanized steel
• Aluminum: aluminized steel

The coating protects the base steel from rust and environmental damage.

The main automotive applications are:

• Body panels (exterior parts):
• Kapilar
• Hoods
• Ceiling panels
• Mudguards

It is used for the following reasons:

• High corrosion resistance (rain, humidity, road salt)
• Smooth surface for painting.
• Long vehicle lifespan
• Structural components:
• Base panels
• Supplements
• Side elements

It is used for the following reasons:

• It maintains its strength while offering resistance to corrosion.
• It improves collision resistance over time.
• Subframe and body parts:
• Chassis components
• Cross elements
• Suspension assembly areas

It is used for the following reasons:

• Excellent protection against mud, salt, and water.
• Exhaust systems (aluminized steel):
• silencers
• exhaust pipes

It is used for the following reasons:

• High heat and oxidation resistance.
• Longer service life at high temperatures.
• Interior panels and hidden parts:
• Door interior panels
• Interior of the luggage compartments

It is used for the following reasons:

• Cost-effective corrosion protection for invisible parts.

The processing methods for metal-coated steel sheets and strips are as follows:

• Forming: Stamping, bending, and deep drawing are used to form body parts. Coatings must be ductile to prevent cracking.
• Source: Spot welding is commonly used. The type of coating affects the welding parameters (e.g., galvanized vs. galvanneal).
• Painting: The surface is pre-treated (phosphating, cleaning). Electroplating (E-coating) further enhances corrosion resistance.

The advantages of using metal-coated steel sheets and strips in the automotive industry are as follows:

• Corrosion resistance: longer vehicle lifespan.
• Lighter compared to thicker uncoated steel.
• Good moldability: complex shapes are possible.
• Cost-effective protection compared to stainless steel.
• Compatibility with coatings and paints

Standards developed for these types of materials define the following:

• Coating thickness (e.g., zinc value in g/m2)
• Mechanical properties (strength, elongation)
• Surface quality (for painting)
• Test methods (corrosion, adhesion)

These standards ensure the following:

• Consistent quality among suppliers.
• Safety and durability of vehicle components.
• Compliance with environmental and warranty requirements.

The Suzuki SES N 3125 standard covers metallic coated steel sheets and strips, such as those listed below:

• Hot-dip galvanized steel (zinc)
• Electrogalvanized steel
• Aluminum-coated or aluminum-silicon-coated steel
• Zinc-aluminum-manganese alloy coatings (advanced corrosion-resistant steels)

These coatings are applied to improve corrosion resistance, durability, and surface performance. In general, coated steels are widely used in the automotive and other industries because they combine the following:

• Basic steel strength
• Corrosion-resistant metallic layer

Metal-clad steel sheets are crucial in the automotive industry because vehicles operate in harsh environments (humidity, salt, temperature variations). Their main benefits include:

• Corrosion resistance: Zinc/aluminum coatings act as a protective layer. They prevent rusting on body panels and structural parts.
• Moldability: Can be stamped into complex shapes (doors, hoods, reinforcements).
• Weldability: Compatible with resistance spot welding used in automotive bodies.
• Surface quality: Suitable for painting (important for visible exterior parts).

SES N 3125 materials are commonly used in the automotive industry in the following areas:

• The fuselage and exterior
• Exterior panels (doors, roof, hood)
• Fenders and side panels
• Structural components
• Base panels
• Supplements
• Cross elements
• Corrosion-susceptible areas
• Wheelbases
• Lower body components
• Fuel system components (with special coatings)

For example, modern coated steels (such as galvanized or galvanized sheet metal) are widely used in vehicles because they provide long-term corrosion protection and good machinability.

In general, the SES N 3125 standard defines the following:

• Material properties:
• Mechanical properties (yield strength, tensile strength)
• Elongation (formability)
• Coating requirements:
• Coating type (zinc, zinc-iron, aluminum-silicon, etc.)
• Coating thickness (g/m2)
• Coating adhesion
• Surface quality
• Surface finish (for painted or exposed parts)
• Error limits
• Corrosion performance
• salt spray resistance
• Environmental durability
• Test methods
• Coating weight tests
• Bending tests
• Adhesion tests
• Corrosion tests

The SES N 3125 standard is considered necessary for the following reasons:

• It ensures corrosion resistance: Vehicles should last 10-15 years without significant rusting problems.
• It guarantees production compatibility:
• Pressing
• Source
• Painting
• It ensures global consistency: Different suppliers offer the same material performance.
• It ensures safety and quality: Structural components must retain their strength even after coating and shaping.
• Complies with environmental regulations: Controls the coating composition (e.g., limits harmful substances)

In short, the SES N 3125 standard was developed for corrosion-resistant coated steel plates used in vehicles. It provides the following:

• Steel does not rust easily.
• The parts can be shaped and welded.
• Suitable for surface painting.
• Quality is consistent among suppliers.

Metal-clad steel sheets are very important in automotive manufacturing because they combine the following properties:

• The strength of steel
• Corrosion resistance of coatings
• Production efficiency

It is used everywhere, from visible body panels to hidden structural components, and helps vehicles last longer while maintaining cost effectiveness.

For many years, our organization, with its competent and experienced team, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the SES N 3125 standard.