1.Tool karfe wani nau'i ne na kayan aiki na karfe wanda aka tsara don amfani da kayan aiki da kayan aiki da kayan aiki.An tsara abun da ke ciki don samar da haɗin kai, ƙarfi, da juriya.Karfe na kayan aiki yawanci ya ƙunshi babban adadin carbon (0.5% zuwa 1.5%) da sauran abubuwa masu haɗawa kamar chromium, tungsten, molybdenum, vanadium, da manganese.Dangane da aikace-aikacen, karafa na kayan aiki na iya ƙunsar wasu abubuwa iri-iri, kamar nickel, cobalt, da silicon.
2.Haɗin ƙayyadaddun abubuwan haɗin da aka yi amfani da su don ƙirƙirar ƙarfe na kayan aiki zai bambanta dangane da abubuwan da ake so da aikace-aikacen.Karfe na kayan aiki da aka fi amfani da shi ana rarraba su azaman ƙarfe mai sauri, ƙarfe mai aikin sanyi, da ƙarfe mai zafi.”