Both grades look identical on day one. Here is how corrosion, cost and finish differ once the keyboard is in the field.两种材质出厂时外观相同，但投入现场后在耐腐蚀性、成本与表面处理上差异明显。
Most metal keyboards use 304 stainless steel, which offers excellent strength and corrosion resistance for indoor and sheltered outdoor use.
When to upgrade to 316
316 contains molybdenum, which greatly improves resistance to chlorides. Specify 316 for coastal kiosks, ships, swimming pools and food plants using chlorine-based cleaners.
Surface finish matters too
A bead-blasted finish hides scratches and fingerprints; a brushed finish looks premium but shows wear sooner. Passivation after machining restores the protective oxide layer on both grades.
大多数金属键盘采用 304 不锈钢，在室内及有遮蔽的户外环境中强度与耐腐蚀性均表现出色。
何时升级到 316
316 含钼，大幅提升抗氯化物腐蚀能力。沿海自助终端、船舶、游泳馆以及使用含氯清洁剂的食品工厂应选用 316。
表面处理同样重要
喷砂表面可隐藏划痕与指纹；拉丝表面更显高档，但磨损痕迹更早显现。加工后的钝化处理可为两种材质恢复保护性氧化层。
