粗鋼 is read as そこう (sokou) and means crude steel.
そこう
sokou
そまつ
crude
そだい
coarse
あらい
あらすじ
outline
そしな
gift given out by companies to customers as a token of gratitude
そあく
そや
rustic
そぼう
rough (behaviour, temperament, etc.)
あらけずり
rough-hewn
そざつ
そだいうんどう
gross motor skill
そほうのうぎょう
extensive agriculture