ISO 27831-1:2008

Overview

ISO 27831-1:2008 - Metallic and other inorganic coatings: Cleaning and preparation of metal surfaces (Part 1: Ferrous metals and alloys) defines standardized processes for cleaning and preparing the surfaces of ferrous metals and alloys prior to further surface treatment. The standard covers removal of unwanted deposits and describes pretreatment methods intended to ensure consistent adhesion, corrosion resistance and quality of subsequent coatings. It applies to non‑corrosion‑resisting steels, cast irons and pure irons, as well as corrosion‑resisting and heat‑resisting steels.

Key topics and technical requirements

• Scope limits: Does not cover heavy removal of oil/grease accumulated during service, welding preparation, or electrical contact cleaning, although methods in the standard may be used at users’ discretion.
• Surface coatings supported: Electrodeposited metals, autocatalytic (chemical) coatings, conversion coatings, hot‑dipped coatings, sprayed metal coatings, diffusion coatings, vitreous enamelling, PVD (Al and Cd), and powder coatings.
• Primary pretreatment processes described:
  • Degreasing (organic‑solvent and alkaline methods)
  • Descaling and descaling by caustic or permanganate
  • Acid pickling and acid dipping (including anodic pickling)
  • De‑rusting (acidic and alkaline de‑rusting)
  • Abrasive cleaning (blasting, tumbling, wire brushing)
  • Chemical smoothing and electropolishing
  • Passivation and contamination tests for stainless and heat‑resisting steels
• Process-to-metal guidance: The standard links cleaning methods and specific preparation sequences to types of ferrous metals and intended coatings (e.g., pretreatment before galvanizing, electroplating, phosphating, metal spraying, enamelling or powder coating).
• Quality and information requirements: Specifies essential information purchasers should supply to processors and includes normative tests and informative annexes on bath maintenance and acidity control.

Applications and who uses it

ISO 27831-1 is used by:

• Coating specifiers and process engineers planning pretreatment workflows
• Electroplaters, galvanizers, metal sprayers and powder coating shops
• Quality managers and inspectors enforcing surface preparation requirements
• OEMs in automotive, aerospace, heavy engineering and construction defining procurement and acceptance criteria

Practical benefits include improved coating adhesion, predictable corrosion performance, reproducible surface cleanliness and clearer supplier/processor communication.

Related standards

• Complements other ISO and industry standards on surface treatment, coating performance and testing. Use ISO 27831‑1 alongside coating‑specific standards and industry best practices when defining pretreatment and inspection requirements.

Keywords: ISO 27831-1:2008, cleaning and preparation of metal surfaces, ferrous metals, degreasing, pickling, descaling, electropolishing, metal surface preparation standard, pretreatment for coatings.