Overview
ISO 4960:2019 specifies minimum requirements for cold‑reduced carbon steel strip with a mass fraction of carbon over 0.25%, supplied in coils or cut lengths. The standard targets products used for highly stressed parts where close dimensional tolerances and controlled surface finishes are critical. It covers grades (CS30–CS95), chemical composition and limits, production and ordering conditions, surface finishes, tests, inspection and marking. The document excludes alloy steels and stainless steels.
Key topics and requirements
- Grades and chemistry: Defines grades CS30 through CS95 with carbon ranges (approximately 0.28% up to 1.03%) and specified limits for Mn, P, S, Si and additional elements (Cu, Ni, Cr, Mo, Nb, V, Ti). Sum limits (e.g., Cu+Ni+Cr+Mo ≤ 0.50% on heat analysis) are included unless otherwise agreed.
- Dimensions and form: Typical thicknesses are 6 mm and under, widths up to 600 mm, available as coils or cut lengths. Wider widths may be agreed between purchaser and producer.
- Surface finishes and roughness: Standardizes finishes - matte, regular bright, plating bright, and best bright - with typical Ra ranges (matte ~0.5–2.0 µm; regular bright ~0.5 µm; plating bright ≤0.25 µm; best bright ≤0.10 µm).
- Manufacture and ordering conditions: Allows for manufacturer discretion in steelmaking unless specified; ordering options include full‑hard, spheroidized annealed, and other conditions (e.g., quenched as specified).
- Mechanical requirements & testing: Specifies hardness (HRBW) and tensile testing requirements, with referenced test methods (Vickers, Rockwell, tensile at room temperature).
- Quality control: Includes heat analysis, optional purchaser product analysis, sampling, decarburization limits, retests, inspection and acceptance criteria, coil size, oiling and marking.
Applications and users
ISO 4960:2019 is intended for:
- Steel producers and strip mills manufacturing cold‑reduced carbon strip
- Purchasing and specification engineers who select materials for highly stressed components
- Quality and metallurgical inspectors performing heat/product analysis, hardness and tensile testing
- Converters, stampers and finishers requiring controlled surface finish for painting, plating or subsequent forming
Typical practical uses include precision parts where tight thickness tolerances, controlled surface roughness and defined mechanical properties are required.
Related standards
Normative references cited in ISO 4960:2019 include:
For procurement, design and quality control, reference ISO 4960:2019 when specifying cold‑reduced steel strip (carbon >0.25%) to ensure consistent chemistry, surface finish and mechanical performance.
