Annealing, Work-hardening and Planishing
退火、加工硬化与打平的关系
标签：加工硬化, 再结晶, 退火温度, 打平窗口, 紫铜
紫铜在锤打下会加工硬化，越打越硬、越易裂，因此打平必须在"软化窗口"内进行。理想状态是：退火后趁软快速打平，硬化到手感发滞就再退火。紫铜再结晶温度约 200–300°C，实际退火加热至暗红（约 500–600°C）后入水或缓冷皆可，关键是消除晶格畸变恢复延展性。
Copper work-hardens under hammering—it gets harder and more brittle—so planishing must occur within a "soft window". Ideally: anneal, planish while soft, then re-anneal once it feels sluggish. Copper recrystallises around 200–300°C; practically heat to a dull red (~500–600°C) and quench or cool slowly—either removes lattice distortion and restores ductility. ---