Iron ƙwanƙwasa sananne ne kuma ana maraba da tsarin simintin gyare-gyaren harsashi. Ƙarfin simintin gyare-gyare yana samun graphite nodular ta hanyar tafiyar matakai na spheroidization da maganin inoculation, wanda ke inganta kayan aikin injiniya yadda ya kamata, musamman filastik da taurin, don samun ƙarfi fiye da carbon karfe. Ƙarfin simintin gyare-gyare shine babban ƙarfin simintin ƙarfe mai ƙarfi tare da cikakkun kaddarorinsa suna kusa da ƙarfe. Dangane da kyawawan kaddarorin sa, an yi amfani da baƙin ƙarfe mai ƙwanƙwasa cikin nasara don jefa sassan runduna masu rikitarwa, ƙarfi, tauri da juriya. Ana amfani da baƙin ƙarfe sau da yawa don samar da sassa na crankshafts da camshafts don motoci, tarakta, da injunan konewa na ciki, da kuma matsakaitan matsa lamba don injuna gabaɗaya.