[f. BLOOM v.2 + -ING1.] The reducing of cast- or pig-iron into ‘blooms.’
1812. Sir H. Davy, Chem. Philos., 392. In the process for reducing cast iron into malleable iron called blooming.
1871. Trans. Amer. Inst. Mining Eng., I. 203. This first reduction or blooming is usually done in this country in a 30-inch 3-high rolling mill.
attrib. 1884. Imp. & Mach. Rev., 1 Dec., 6719/2. Adjacent to this … the roughing mill, together with a … blooming mill.
