ISO 6435:2024

Overview - ISO 6435:2024 (Stainless steel bars for the reinforcement of concrete)

ISO 6435:2024 is the first-edition international standard that specifies technical requirements for hot‑rolled stainless steel plain bars and ribbed bars used as reinforcement in concrete. Published April 2024, the standard covers products delivered as bars, coils and de‑coiled products and clarifies that it does not apply to ribbed bars produced from finished products. The production process is left to the manufacturer’s discretion.

Key SEO terms: ISO 6435:2024, stainless steel bars, reinforcement of concrete, ribbed bars, plain bars, hot rolled.

Key topics and technical requirements

ISO 6435:2024 organizes practical requirements and test methods for stainless steel reinforcing bars. Major topics include:

• Scope and definitions - Defines stainless steel bars (≥ 10.5 % Cr, ≤ 1.2 % C) and product forms (bars, coils, de‑coiled).
• Dimensions and mass per unit length - Nominal diameters, cross‑sectional areas and tables of mass per unit length with permissible deviations for different stainless grades.
• Rib requirements - Minimum rib geometry and distribution requirements for ribbed bars (transverse ribs, at least two rows).
• Chemical composition - Cast‑analysis composition limits and rules for product analysis and permissible deviations.
• Mechanical properties - Requirements for tensile strength, proof strength, elongation, bending, rebending after ageing, and special impact requirements for duplex (austenitic‑ferritic) steels.
• Corrosion resistance & magnetic permeability - Test requirements and acceptance criteria to ensure long‑term performance in concrete.
• Testing, inspection and conformity - Specified tests (tensile, bend, rebend, impact, chemical, magnetic and corrosion tests), evaluation of production conformity and acceptance testing of deliveries.
• Designation, marking and delivery - Marking on bars, bundle identification, delivery lengths and permissible length deviations; options for manufacturer–purchaser agreement are provided.

Practical applications and users

ISO 6435:2024 is intended for anyone specifying, producing or testing stainless steel reinforcing bars for concrete applications:

• Manufacturers and steel producers - to design, manufacture and mark compliant hot‑rolled plain and ribbed bars.
• Rebar suppliers and fabricators - for ordering, identification and acceptance testing of deliveries.
• Structural and civil engineers, specifiers and contractors - to select appropriate stainless rebar grades and ensure compliance for durable reinforced concrete in aggressive or corrosive environments.
• Testing laboratories and inspection bodies - to perform tensile, bend, corrosion and magnetic permeability tests in accordance with the standard.

Typical uses include reinforced concrete for infrastructure, marine structures, bridges, tunnels, chemical plants and buildings where corrosion resistance and long service life are required.

Related standards

ISO 6435 references and complements other standards, including:

• ISO 6935‑1 / ISO 6935‑2 (steel for reinforcement - plain and ribbed bars)
• ISO 15510 (stainless steels - chemical composition)
• ISO 15630‑1 (test methods for reinforcing bars)
• ISO 148‑1 (Charpy impact test)
• EN 196‑1, EN 197‑1 (cement testing and specifications)

For procurement and specification, reference ISO 6435:2024 alongside these complementary standards to ensure complete technical coverage.