大連數控加工中鋁表面發黑原因是鋁制品被氧化而發黑，建議不清除，氧化鋁在空氣中較為穩定。很難再氧化。可以保護內部的鋁不被氧化。 鋁：銀白色輕金屬。有延展性。商品常制成棒狀、片狀、箔狀、粉狀、帶狀和絲狀。在潮濕空氣中能形成一層防止金屬腐蝕的氧化膜。

鋁粉和鋁箔在空氣中加熱能猛烈燃燒，并發出眩目的白色火焰。易溶于稀硫酸、硝酸、鹽酸、氫氧化鈉和氫氧化鉀溶液，難溶于水。相對密度2.70。熔點660℃。沸點2327℃。鋁元素在地殼中的含量僅次于氧和硅，居第三位，是地殼中含量最豐富的金屬元素。航空、建筑、汽車三大重要工業的發展，要求材料特性具有鋁及其合金的獨特性質，這就大大有利于這種新金屬鋁的生產和應用，應用較為廣泛。

The reason for the blackening of aluminum surface in Dalian CNC machining is that aluminum products are oxidized and blackened, and it is recommended not to remove them. Aluminum oxide is relatively stable in air. It's difficult to oxidize again. It can protect the internal aluminum from oxidation. Aluminum: Silver white light metal. Has extensibility. Products are often made into rods, sheets, foils, powders, strips, and filaments. A layer of oxide film can be formed in humid air to prevent metal corrosion.

Aluminum powder and aluminum foil can burn fiercely when heated in the air, emitting dazzling white flames. Easy to dissolve in dilute sulfuric acid, nitric acid, hydrochloric acid, sodium hydroxide, and potassium hydroxide solutions, but difficult to dissolve in water. The relative density is 2.70. Melting point 660 ℃. Boiling point 2327 ℃. Aluminum is the third most abundant metal element in the Earth's crust, after oxygen and silicon. The development of the three important industries of aviation, construction, and automobiles requires materials with unique properties of aluminum and its alloys, which greatly facilitates the production and application of this new metal aluminum and has a wide range of applications.