Overview
EN ISO 6158:2018 - "Metallic and other inorganic coatings - Electrodeposited coatings of chromium for engineering purposes" (ISO 6158:2018) is a CEN-adopted international standard that specifies requirements for electroplated metallic chromium coatings, with or without undercoats, on ferrous and non‑ferrous metals. The standard provides a coating designation system (including thickness and surface quality) and describes required tests, sampling and documentation needed when specifying chromium plating for engineering applications.
Key topics and technical requirements
- Scope and designation: Guidance for specifying chromium coating type and thickness appropriate for engineering uses (Clauses 1 and 5). Designation covers basis metal, heat treatment, coating type and final surface roughness.
- Information from purchaser: Clause 4 lists the information a purchaser must supply (functional and surface engineering requirements) so processors can meet application needs.
- Performance requirements (Clause 6):
- Appearance, surface finish and roughness - final texture and roughness quality requirements, with classifications (Clause 6.2–6.4, 6.14; Annex D).
- Thickness measurement - methods and tolerance requirements (Clause 6.4; Annex B).
- Mechanical and integrity checks - hardness, adhesion, porosity, and crack/void assessment (Clauses 6.5–6.7; Annex C).
- Thermal treatments and embrittlement control - stress‑relief and hydrogen‑embrittlement‑relief heat treatments before/after plating (Clauses 6.8–6.9).
- Pre‑ and post‑treatment processes - peening, use of undercoats (e.g., nickel for corrosion protection), stripping and multilayer strategies for corrosion resistance (Clauses 6.10–6.13).
- Sampling and test specimens: Requirements for representative testing (Clause 7; Annex A lists typical thicknesses used in engineering).
Applications and who uses this standard
EN ISO 6158:2018 is used where durable functional chromium plating is required:
- OEM design and specification teams (automotive, aerospace, hydraulics, tooling)
- Surface‑treatment and electroplating processors
- Quality assurance and testing laboratories
- Procurement and maintenance engineers specifying wear, friction, fretting or corrosion resistance
- Standards writers and regulatory compliance officers
Practical benefits include consistent coating performance, verifiable thickness and adhesion, and reduced risk of hydrogen embrittlement or premature failure.
Related standards
Relevant normative references cited in EN ISO 6158:2018 include:
- ISO 1463 - coating thickness measurement (microscopical)
- ISO 2064 - measurement definitions and conventions
- ISO 2080 - surface treatment vocabulary
- ISO 3497 - metallic coatings thickness measurement
For implementation details, safety and environmental controls (hexavalent chromium handling), consult the full EN ISO 6158:2018 text and local regulations before application.