NACE 25.6 – Treatment and Coating of Metals; Machining | Public Tenders

Definition: NACE 25.6 covers surface treatment (electroplating, powder coating, galvanising, anodising), heat treatment (hardening, annealing, tempering) and machining (turning, milling, grinding) as subcontract manufacturing for other industries.

Legal basis: NACE Rev. 2 (Regulation (EC) No 1893/2006) · Last updated: January 2026

What does NACE 25.6 cover?

NACE 25.6 (Surface treatment, heat treatment, machining) classifies specialised contract service providers for metal finishing — essential partners for public construction and procurement projects involving metal components.

Electroplated coatings (galvanising, chrome plating, nickel plating), powder coating for façade elements, hot-dip galvanising of steel components and machining of precision parts are typical services in this group.

Public tenders: surface-treatment tenders

Services from NACE 25.6 are an integral part of many public contracts — as sub-services in construction and supply contracts or as standalone service tenders.

Typical contract types

• Hot-dip galvanising of steel components: railings, masts, bridge parts and noise barriers are hot-dip galvanised for corrosion protection
• Powder coating of public infrastructure: road signs, street furniture, fences and gates in municipal colours
• Electroplated coatings for precision parts: coating services for measuring devices, fittings and precision mechanics
• Heat treatment for tools and machine parts: hardening services for public workshops and maintenance operations
• CNC machining services: subcontract manufacture of spare parts for public installations and vehicles

Relevant CPV codes

Contracting authorities and bidders

Public contracting authorities

Civil-engineering and building departments that require corrosion protection for steel components, municipal workshops and depots, the armed forces (maintenance of vehicles and equipment) and rail-infrastructure operators are typical contracting authorities. Services from NACE 25.6 are frequently awarded as sub-services to construction companies.

Bidders and eligibility requirements

• Quality standards: ISO 1461 for hot-dip galvanising, EN ISO 12944 for corrosion-protection coatings
• Environmental certifications: electroplating operations are subject to strict water-protection permits; ISO 14001 is frequently required
• ECHA compliance: REACH-compliant coating materials, exclusion of RoHS-relevant substances
• Process certifications: Nadcap certification for aerospace coatings

Frequently asked questions on NACE 25.6 and public tenders

Are surface-treatment services awarded as supply or service contracts? Subcontract coating and machining without a substantial material component are service contracts. As soon as the coated or machined product predominates, a supply contract may apply. The classification influences the applicable threshold.

What corrosion-protection classes are typically required for public construction? Under EN ISO 12944, corrosivity categories C3 to C5 (outdoor, industry, marine climate) are prescribed depending on the environment. Public contracting authorities frequently reference ZTV-Kor (Additional Technical Contract Conditions for Corrosion Protection) for steel structures.

• NACE C – Manufacturing: parent section
• NACE 25 – Fabricated metal products: parent division
• NACE 25.5 – Forgings: upstream manufacture
• NACE 25.9 – Other fabricated metal products: further metal products

Last updated: January 2026 All information provided without warranty. For legally binding advice, please consult a law firm specialising in public procurement.