ʻO ka mea o ka pā kila kalapona he kila kalapona maʻemaʻe a i ʻole ke kila kalapona, ʻo ia ke kila me ka ʻona kalapona ma lalo o 2.11% a ʻaʻohe mea metala i hoʻohui ʻia.Ma waho aʻe o ke kalapona, loaʻa pū kekahi mea liʻiliʻi o ka sulfur, silicon, phosphorus, manganese a me nā mea ʻē aʻe.Hiki ke hoʻokaʻawale ʻia nā papa kila kalapona i ke kalapona haʻahaʻa, kalapona kalapona a me ke kalapona kiʻekiʻe e like me ka ʻike kalapona;e like me ka noi, hiki iā lākou ke hoʻokaʻawale ʻia i nā mea hana, nā hale, a me ka ʻoki ʻoki manuahi;e like me ke ʻano deoxidation, hiki ke hoʻokaʻawale ʻia i ke kila paila, ke kila semi-kiled, ke kila pepehi ʻia, a me ke kila make kūikawā;Wahi a ke ala o ka hoʻoheheʻe ʻana, hiki ke hoʻokaʻawale ʻia i ke kila converter, open hearth furnace steel a me ka uila uila.Hoʻokomo nui ʻia ka papa carbon Q195, Q215, Q235, Q255, Q275 etc.