4 · Society, Civilization, Culture
47 · crafts and industries
47B · handicrafts and industries
47B2 · industries
47B21 · industries ~ metal
47B211 · iron and steel industry
47B211(+1) · iron and steel industry (+ place ~ crafts, industries, agriculture)
47B211(+11) ·
iron and steel industry (+ indoors; in laboratory, factory, barn, etc.)