Lissafin ƙari na abubuwan da aka gyara na narkakken ƙarfe a cikin tanderun narkewa:

gt=Gz(Xa-Xb)/Cd(kg)

gt – Ƙara adadin C-ƙara wakili ko wasu gami (kg)

Gz – Jimlar nauyin narkakkar baƙin ƙarfe a cikin tanderu (kg)

Ƙimar Xa-manufa na narkar da baƙin ƙarfe (%)

Xb –Kimar narkakkar ƙarfe a cikin tanderun (%)

Wakilin haɓaka CC ko wani abun ciki na gami (%)

d- Yawan sha na kayan aiki masu aiki (100% shine 1)

Narkar da baƙin ƙarfe C da SI sun zarce abun da aka yi niyya, ƙara tarkace don rage C, lissafin SI gt=Gz(Xb-Xa)/b

b-abun ciki na abin da aka gyara a cikin tarkace

Haƙiƙanin bayanai shine: ƙara 34kg guntun baƙin ƙarfe/t, rage 0.1% C kuma rage 0.05% Si