SG Iron (Spheroidal Graphite Iron): Properties, Grades, and Applications 

For demanding industrial applications requiring superior strength and ductility, Spheroidal Graphite Iron, commonly known as SG Iron or Ductile Iron, is an exceptional engineering material. Its unique microstructure delivers performance characteristics far exceeding those of standard grey cast iron, making it a reliable choice for critical components in the automotive, energy, and heavy machinery sectors. 

Nifty Alloys LLC is a premier supplier of high-integrity SG Iron in the UAE and the broader GCC region. We provide a comprehensive stock of SG Iron grades, compliant with international standards like BS2789 and ASTM A536, ensuring your projects are built on a foundation of certified quality and material reliability. 

What is SG Iron?

SG Iron, also referred to as Ductile Iron or Nodular Cast Iron, is a type of cast iron distinguished by the spherical or nodular shape of its graphite content. This is a significant departure from traditional grey cast iron, where the graphite exists as sharp flakes. These flakes create internal stress points, rendering the material brittle and prone to fracture under tension. 

The development of SG Iron in the mid-20th century was a pivotal moment in metallurgy. By introducing a small amount of a nodulizing agent, typically magnesium, into the molten iron just before casting, the graphite precipitates into compact spheroids. This seemingly minor change in the microstructure eliminates the internal stress concentrations, resulting in a material that is not only strong but also remarkably ductile—capable of deforming under load without fracturing. This combination of properties gives SG Iron a unique position between grey cast iron and cast steel.