EN ISO 2081 Metallic and other inorganic coatings - Zinc coatings with additional treatments on iron or steel, a European standard subsequently published by the International Organization for Standardization (ISO), specifies the requirements for electrolytic coating of zinc coatings with additional treatments on iron or steel. This standard includes the information to be provided by the purchaser to the electrolytic applicator and the requirements for pre- and post-electrolytic heat treatment.
This standard does not apply to the following coatings:
This standard does not specify the surface condition requirements of the base metal before electroplating with zinc. However, imperfections on the surface of the base metal can adversely affect the appearance and performance of the coating. The coating thickness that can be applied to threaded components may be limited by dimensional requirements, including grade or fit.
Zinc coatings are applied to iron or steel articles for protective and decorative purposes by electroplating with acidic zinc chloride, alkaline non-cyanide zinc, and alkaline zinc cyanide solutions. Bright zinc coatings by electroplating are popular, and bright zinc coating preparation processes are widely used.
The ability of a zinc coating to prevent corrosion depends on its thickness and the type of service conditions it is exposed to. For example, the corrosion rate of zinc is generally higher in industrial environments than in rural areas. Therefore, the type of service conditions should be taken into account when determining the minimum coating thickness. Trivalent chromate conversion coatings and other finishing treatments applied after electroplating enhance the corrosion resistance of electroplated zinc coatings.
Because the appearance and usability of zinc coatings depend on the surface condition of the base metal, agreement must be reached between the parties involved that the surface quality of the base metal is sufficient for electroplating. Trivalent chromate conversion coatings are removed or replaced with other conversion coatings at the specific request of the purchaser. This standard provides codes for all types of chromate conversion and other complementary coatings.
For conversion coatings that do not contain hexavalent chromium, ISO 19598 applies. This standard applies only to zinc, zinc-iron, and zinc-nickel coatings where trivalent systems are required.
Due to REACH regulations, the use of hexavalent chromium compounds is prohibited in Europe except where specifically authorized. Alternative conversion coatings or substitutes may be used and must meet the corrosion requirements specified in this standard.
Corrosion is a persistent problem in the manufacturing and construction industries, particularly for iron and steel products exposed to harsh environmental conditions. One widely used method for improving corrosion resistance is zinc electroplating. The EN ISO 2081 standard provides a comprehensive framework for applying electroplated zinc coatings to iron and steel, ensuring consistency, quality, and performance across various industries.
This standard specifies requirements for zinc coatings applied by electroplating to iron or steel objects, including fasteners, automotive components, and construction hardware. It also covers finishing processes, such as chromate conversion coatings, that improve corrosion resistance and appearance.
The EN ISO 2081 standard defines minimum coating thicknesses depending on environmental exposure and required durability. Typical classes are:
Thicker coatings provide greater corrosion resistance but may be less suitable for precision-fit components.
This standard allows different surface treatments, including:
Appearance is not necessarily related to corrosion protection, which is determined primarily by coating thickness and finish.
To improve corrosion resistance, the standard specifies optional chromate conversion coatings (passivation) treatments, including:
These processes may involve trivalent chromium or hexavalent chromium. Due to environmental and health concerns, hexavalent chromium processes are heavily restricted in European Union countries under REACH regulations.
EN ISO 2081 addresses the issue of hydrogen embrittlement, which is particularly critical for high-strength steels. It recommends post-coating baking treatments to reduce hydrogen-induced cracking in susceptible materials.
Common test methods specified in this standard are:
The EN ISO 2081 standard is widely applied in the following industries where iron or steel components require corrosion-resistant protection:
With the increasing emphasis on sustainable production, the use of hexavalent chromium is being phased out in many applications. The EN ISO 2081 standard allows for more environmentally friendly alternative passivation systems that meet corrosion resistance requirements.
As a result, EN ISO 2081 is a fundamental standard for manufacturers and engineers involved in the surface treatment of steel components. By providing a standardized approach to zinc electroplating, it enhances the reliability, appearance, and service life of metal parts in a variety of environments. As global industries strive for more sustainable practices, compliance with this standard, particularly for environmentally friendly passivation methods, has become more important than ever.
Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the EN ISO 2081 "Metallic and other inorganic coatings - Zinc coatings with additional treatments on iron or steel" standard.
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