The monograph contains information about the global trends in improving the properties of Ni-Hard cast iron. The influence of alloying elements on the main consumer properties of nihards is considered. The results of research on improving the properties of nihards by changing the composition and structure are presented. The composition of HS for casting parts of their nihards is proposed, which ensures high quality of the mold and casting.The monograph is intended for scientific and engineering workers in the metallurgical and engineering industries, doctoral students, undergraduates and university students.This research is funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08855477 Developing and implementing the technology of producing the Nihard class cast irons with increased operational properties for mining and processing quipment parts).