T 1600 1538℃-------- 1500 1400 1324℃-⑧-Fe_ 1300 1200 Y-Fe 1100 出 912℃ a-Fe cooling curve if pure ironcooling curve if pure iron 1394℃ 1538℃ 1000 600 800 1200 t 1600 1500 500 700 900 1100 1300 1400 912℃ δ - Fe α - Fe γ - Fe T