The making of steel — the whole industrial process of turning iron ore into steel, with all the furnaces, heat and machinery that involves. It is not a company and not a person; it is the activity, and so it is uncountable. You will nearly always see it doing one of two jobs. First, as a plain noun: 'steelmaking uses enormous amounts of energy', 'the history of steelmaking in this valley'. Second, sitting in front of another noun to describe it: steelmaking capacity, a steelmaking plant, the steelmaking industry. This second use is the more common one in the news. The word turns up wherever people discuss heavy industry, jobs in old factory towns, or climate change — steelmaking is one of the largest producers of carbon dioxide on earth, so it appears constantly in that conversation. It is neutral and technical, at home in reports and articles rather than in talk.

煉鋼（這個產業活動、製程）。不是公司也不是人，是「做鋼這件事」；常見於「煉鋼廠 a steelmaking plant」「煉鋼產能 steelmaking capacity」這類搭配。