ɪnstˈɛd ʌv ɪnɪfˈɪʃəntli ˌɪntɹədˈuːsɪŋ kˈɑːɹbən æt ðə sˈɜːfɪs wɪð kˈoʊl, kɹˈʌp ˈɑːɹmɚɹ ɐtʃˈiːvd ɡɹˈeɪɾɚ dˈɛpθ ʌv kˈɑːɹbən sᵻməntˈeɪʃən baɪ ɐplˈaɪɪŋ kˈɑːɹbənbˈɛɹɪŋ ɡˈæsᵻz kˈoʊl ɡˈæs ɔːɹ ɐsˈɛɾəlˌiːn tə ðə hˈiːɾᵻd stˈiːl.
Instead of inefficiently introducing carbon at the surface with coal, Krupp armour achieved greater depth of carbon cementation by applying carbon-bearing gases (coal gas or acetylene) to the heated steel.