Presented paper deals with the technology of production of ductile iron on industrial scale. Particularly, the material in question is EN-GJS-400-18-LT, which is suitable for castings intended for extreme conditions. Drawing on previous works, most attention has been paid to the implementation of the cored wire technology for modification and primary inoculation. Two technological options were compared, namely modification and primary inoculation by the pour method in the ladle and modification and primary inoculation by the cored wire using a twin-core feeder. Test samples within the inlet system of the moulds were cast during the pouring process to analyse the chemical composition, evaluate the microstructure and perform mechanical tests without interfering with the casting itself. The chemical composition was determined by optical emission spectrometry and combustion analysis. Metallographic analysis and microstructure evaluation were performed by optical microscopy and image analysis. Mechanical properties testing was focused on tensile test, impact test and hardness test. It was demonstrated that the foundry is capable of producing ductile iron of the required quality with the adoption of modern cored wire technology.