Steel Browning & Bluing
钢铁发蓝与发黑
标签：发蓝, 发黑, 钢铁, 教程
钢铁的化学着色为发蓝（bluing）与发黑（browning），生成 Fe₃O₄ 氧化膜，呈深蓝黑至黑色，兼具装饰与防锈。工艺路线：①**碱性发黑**（工业主流）：氢氧化钠+亚硝酸钠高温（135–150℃）煮黑，膜致密耐磨②**常温发蓝**（枪械/小件）：专用发蓝液反复涂擦，色较浅③**热发蓝**：加热钢件至 280–320℃ 后浸入热油或蜡。前处理必须除油除锈（酸洗），后处理必须脱水防锈（浸油或蜡封）。注意亚硝酸盐有毒，须通风与防护。
Steel's chemical coloring is bluing/browning, forming an Fe₃O₄ film from deep blue-black to black — decorative and rust-resistant. Routes: ①**alkaline blackening** (industrial standard): sodium hydroxide + nitrite at 135–150℃, dense and wear-resistant ②**cold bluing** (firearms/small parts): repeated application of bluing solution, lighter color ③**hot bluing**: heat to 280–320℃ then quench in hot oil or wax. Pre-treat by degreasing and pickling; post-treat by dewatering and rust-proofing (oil or wax). Nitrites are toxic — ventilate and use PPE. ---