Grain-growth Control in Repeated Anneals
反复退火的晶粒长大控制配方
标签：晶粒度, 退火温度, 时间控制, 防粗晶
折叠成型常需 5–10 次退火，累计高温会令晶粒长大、表面出现橘皮。控制配方：铜 450–480 ℃/15 min 保温后空冷（而非 600 ℃ 以上），黄铜 430–450 ℃；晶粒度可稳定在 0.03–0.05 mm。厚件或多次成形件改用 400 ℃ × 25 min 的低温多次方案。橘皮已出现时，最后道次前重新冷轧 8–10% 再退火可细化表面晶粒。
Fold forming needs 5–10 anneals; cumulative heat coarsens grains and gives orange-peel surface. Recipe: copper at 450–480 °C for 15 min then air cool (not above 600 °C), brass at 430–450 °C, holding grain size at 0.03–0.05 mm. For heavy or long runs, use 400 °C × 25 min low-temp multiple anneals. If orange peel appears, cold-roll 8–10% before the final anneal to refine the surface grains. ---