ISO 19598:2016

Overview

ISO 19598:2016 specifies requirements for electrodeposited zinc and zinc-alloy coatings on iron or steel with Cr(VI)-free passivation. It covers zinc coatings and zinc-alloy systems containing nickel (ZnNi, 12–16 % Ni) or iron (ZnFe, 0.3–1.0 % Fe). The main objective is to define designation, minimum corrosion resistance, and minimum coating thicknesses for electroplated zinc/zinc-alloy coatings used to protect steel components against corrosion.

Key topics and technical requirements

• Scope and designation: Standardized nomenclature for coatings (e.g., Fe//ZnNi8//Cn//T0) that records base material, alloy type, nominal local thickness and passivation/post-treatment.
• Coating types: Zn (pure zinc), ZnFe (0.3–1.0 % Fe), ZnNi (12–16 % Ni).
• Cr(VI)-free passivation: Passivation types and colour codes - An (transparent), Cn (iridescent/coloured), Fn (black). Passivations may be dyed.
• Post treatments: Definitions and symbols for sealants and top coats (T0, Tx, T2, T7, etc.). Sealants are typically ≤2 µm; top coats are >2 µm and Cr(VI)-free.
• Performance requirements: Minimum corrosion resistance defined via specified accelerated test methods (e.g., salt spray tests per ISO 9227 referenced) and minimum local coating thicknesses for functional surfaces.
• Hydrogen embrittlement: Guidance on pre/post treatments and process controls for high-strength steels (tensile strength ≥ 1 000 N/mm²) to mitigate hydrogen embrittlement.
• Process control and documentation: Requirement to record pre-treatment, bath chemistry, processing parameters, monitoring limits and actions for reproducibility.
• Significant surfaces: How to indicate functional areas that must meet corrosion/thickness criteria on drawings.

Applications and practical value

ISO 19598:2016 is used when specifying durable, Cr(VI)-free corrosion protection for iron and steel components subject to environmental exposure. Typical uses include fasteners, stampings, machined parts and assemblies where zinc or zinc-alloy electroplating is selected for sacrificial and barrier protection. The standard helps purchasers, designers and electroplaters ensure consistent coating performance, traceability and testable acceptance criteria.

Who should use this standard

• Electroplating service providers and process engineers
• Purchasing/specification engineers and OEMs
• Quality managers and test laboratories
• Product designers selecting corrosion protection for steel components

Related standards

Normative references in ISO 19598:2016 include ISO 2080, ISO 3497, ISO 3613, ISO 9227, ISO 9587, ISO 9588 and ISO 27830 - covering vocabulary, thickness measurement, chromate conversion tests, salt spray testing and hydrogen embrittlement controls.