ISO 6935-1:2007

Overview

ISO 6935-1:2007 - Steel for the reinforcement of concrete - Part 1: Plain bars defines technical requirements for plain (smooth) steel bars used as reinforcement in concrete. The standard covers nine non‑weldable grades (B240A‑P to B420D‑P) and one weldable grade (B420DWP). It applies to straightened products and plain bars supplied in coil form delivered in straight lengths, while bars produced from finished products (e.g., plates or rails) are excluded. ISO 6935-1:2007 sets expectations for dimensions, chemical composition, mechanical performance, testing, marking and conformity.

Key topics and requirements

• Steel grades and designation: Grades are designated per ISO/TS 4949 (e.g., ISO 6935-1 - 12 B240A‑P). The naming reflects intended use (B = reinforcing steel), characteristic yield strength and other attributes.
• Dimensions & mass: Nominal diameters, cross‑sectional areas and permissible deviations are specified; delivery lengths (commonly 6 m or 12 m) are to be agreed.
• Chemical composition: Maximum element contents and carbon‑equivalent (CEV) rules are given; product analysis tolerances relative to cast analysis are specified.
• Mechanical properties: Tensile properties (upper yield, tensile strength, elongation/ductility class) and bending requirements are defined. If no yield point exists, 0.2% proof strength is used.
• Testing methods: Tensile and bend tests referenced to ISO 15630‑1; chemical analysis by spectrometric or referee methods listed in ISO/TR 9769. Gauge lengths and bend mandrel sizes are specified.
• Marking & designation: Each bundle must be labeled with manufacturer, ISO reference, steel grade, diameter, cast or test reference and origin.
• Conformity & certification: Evaluation via certification schemes (ISO 10144) or acceptance testing of specific deliveries; sampling and statistical verification procedures are described.

Applications and practical use

ISO 6935-1:2007 is used to ensure consistent quality and traceability of plain reinforcing bars in:

• Structural concrete elements where plain bars are specified (foundations, slabs, minor reinforcement).
• Supply chain documentation for procurement and inspection of reinforcing steel.
• Factory QA/QC and laboratory testing regimes to verify chemical and mechanical compliance.
• Contract specifications and construction codes referencing international material standards.

Who should use this standard

• Steel manufacturers and mill quality managers
• Reinforcement suppliers and fabricators
• Structural engineers and specifiers
• Construction contractors and site inspectors
• Material testing laboratories and certification bodies

Related standards

• ISO 6935‑2 (Ribbed bars), ISO 6935‑3 (Welded fabric)
• ISO 15630‑1 (test methods for reinforcing bars)
• ISO/TS 4949 (steel names), ISO 10144 (certification scheme)
• ISO 404, ISO 14284, ISO/TR 9769

Keywords: ISO 6935-1:2007, steel for reinforcement of concrete, plain bars, reinforcing steel grades, tensile properties, chemical composition, bend test, certification.