Ihe nkedo itinye ego n'ígwè isi awọ bụ ngwaahịa nkedo nke usoro ntinye ntinye ego na-efunahụ wụsara n'ebe a na-emepụta ọla. Iron isi awọ (ma ọ bụ nkedo isi awọ) bụ ụdị ígwè-carbon alloy (ma ọ bụ Ferrum-Carbon Alloy) nke nwere microstructure graphite. A na-akpọ ya aha n'ihi agba isi awọ nke mgbaji ọ na-etolite. 
