Bakin karfe rukuni ne na gami da ferrous wanda ya ƙunshi mafi ƙarancin kusan 11% chromium, abun da ke hana ƙarfen tsatsa kuma yana ba da kaddarorin da ke jure zafi.Daban-daban na bakin karfe sun haɗa da abubuwan carbon (daga 0.03% zuwa sama da 1.00%), nitrogen, aluminum, silicon, sulfur, titanium, nickel, jan karfe, selenium, niobium, da molybdenum.Musamman nau'ikan bakin karfe galibi ana tsara su ta lambar lambobi uku ta AISI, misali, bakin karfe 304.