All access covers and frames which are manufactured from spheroidal graphite cast iron are in accordance with ISO 1083 (GRADE GJS 500-7) and EN 1563. This material has an outstanding performance.
The spheroidal structure is achieved by adding the magnesium at the molten stage, which transforms the flakes of graphite.
Spheroidal graphite, or ductile iron, is a unique form of iron which, prior to the casting process, receives a treatment with magnesium or cerium to produce an exceptionally strong, durable and impact resistant metal.
Grey iron is named after presence of carbon, resulting in a composition of thin graphite flakes which are distributed heterogeneously.
Ductile iron's high strength to weight ratio allows for the production of light weight castings that offer up to a 50% weight saving over the traditional grey iron equivalent. It minimises the risk of failure during installation as well as reducing the likelihood of breakage under traffic pressure.
Ductile iron's inherent properties of high tensile strength and resistance to impact allows the waterway area of gully grates to be evenly distributed over the surface of the grating without losing structural strength.