BS2789 Grade 400-15 is a ferritic spheroidal graphite (SG) ductile iron specified to a minimum tensile strength of 400 MPa and minimum elongation of 15% — the most ductile grade in the BS2789 / EN-GJS series. Nifty Alloys supplies EN-GJS-400-15 as continuous cast round bar, flat bar and hollow bar from stock in Dubai, with EN 10204 3.1 mill test certificates, available for immediate dispatch across UAE, GCC and export markets. Stress relief annealing, bandsaw cutting, and third-party inspection are available on request.

What Is BS2789 Grade 400-15 SG Iron?

BS2789 is the British Standard for spheroidal graphite (SG) cast iron — also called ductile iron or nodular iron. The standard classifies grades by tensile strength and elongation: the designation 400-15 means a minimum tensile strength of 400 MPa and a minimum elongation of 15%. In the current European standard EN 1563, this grade is designated EN-GJS-400-15. Both designations refer to the same material.

The defining characteristic of SG iron — and what separates it from grey cast iron — is the form of graphite in its microstructure. During melting, a small addition of magnesium (typically 0.03–0.06%) causes graphite to solidify as compact spheroids (nodules) rather than the sharp flakes found in grey iron. These rounded nodules do not create internal stress concentration points, which dramatically improves tensile strength, elongation, and impact toughness compared to any grey iron grade.

Grade 400-15 is the most ductile grade in the SG iron family. Its ferritic matrix — with minimal pearlite — delivers the highest elongation values, making it the preferred choice where the material must deform plastically before fracture: safety-critical castings, hydraulic components under shock loading, and structural parts requiring fatigue resistance and toughness.