Fe is the basis.
According to GOST 4832-95, cast iron is divided into four groups according to the content of manganese: I group ≤0.30%, II group 0.30-0.90%, III group 0.50-0.90%, IV group 0.90- 1.50%; by the content of phosphorus is divided into 5 classes: class A ≤0,080%, class B ≤0,12%, class B≤0,30%, class G 0,30-0,70%, class D 0,70-1,20 %; for sulfur content is divided into 4 categories: 1 category ≤0,020%, 2 category ≤0,030%, 3 category ≤0,040%, 4 category ≤0,050%. With a mass fraction of chromium of not more than 0.050%, foundry iron is used for the production of castings of cast iron with nodular graphite, with a mass fraction of chromium of not more than 0.040% - for castings of malleable cast iron and with a mass fraction of chromium of not more than 0.10% for castings from gray cast iron. In cast iron smelted from copper-bearing ores, the mass fraction of copper is additionally determined and is indicated in the quality document.