短语词组短语hot -rolling billet 热轧坯料continuous -casting -rolling of sheet billet 薄板坯连铸连轧welding multi billet rolling 焊接小方坯轧制shaped billet rolling machine 异性坯辊道billet rolling train 小胚辊轧系列whole billet rolling 整坯轧制 返回 rolling billet