Karfe ya kashekarfe ne wanda aka lalata shi gaba daya ta hanyar kari na wani wakili kafin yin simintin ta yadda kusan babu wani juyin halitta na iskar gas a lokacin karfafawa. Yana da alaƙa da babban nau'in nau'in sinadarai da 'yanci daga ƙarancin iskar gas.

Karfe da aka kashe da yawa galibin karfe ne, amma carbon monoxide yana barin nau'in nau'in busawa da aka rarraba a cikin ingot. Porosity yana kawar da bututun da aka samu a cikin ƙarfe da aka kashe kuma yana ƙara yawan amfanin ƙasa zuwa kusan 90% ta nauyi. Karfe da aka kashe da yawa ana amfani da shi don tsarin ƙarfe tare da abun ciki na carbon tsakanin 0.15 zuwa 0.25% carbon, saboda ana birgima, wanda ke rufe porosity.

Karfe mai kauri, wanda kuma aka sani da zana ingancin ƙarfe, ba shi da ɗan ƙarami zuwa wani abin da zai hana fitar da siminti wanda ke sa carbon monoxide ya tashi da sauri daga ingot. Wannan yana haifar da ƙananan ramukan busa a saman waɗanda daga baya aka rufe su a cikin tsarin jujjuyawar zafi. Yawancin rimmed karfe yana da abun ciki na carbon da ke ƙasa 0.25%, abun ciki na manganese da ke ƙasa da 0.6%, kuma ba a haɗa shi da aluminum, silicon, da titanium ba.Saboda rashin daidaituwa na abubuwan haɗin gwiwa ba a ba da shawarar ga aikace-aikacen aiki mai zafi ba.