Anh
hardness number
hardness numeral
index of hardness
Đức
Härtegrad
Härtezahl
Pháp
indice de dureté
Härtegrad,Härtezahl /TECH/
[DE] Härtegrad; Härtezahl
[EN] hardness number; hardness numeral; index of hardness
[FR] indice de dureté