11932Copper and Its Alloys

Like that of Al the corrosion resistance of copper decreases on increasing the alloy content. However, in its pure form copper has limited uses due to its softness and lack of strength. Copper alloys have excellent heat transfer properties and therefore find extensive use in heat exchanger applications. The alloys have excellent resistance to seawater environments and are used in marine applications

TABLE 11.15 Examples of Aluminum and Aluminum Alloy Grades and Their Uses

Grade/Type Comment and Uses

Wrought 99Al. Acetic acid tanks pumps and handling equipment.

Commercially pure Typical corrosion rates; (mm/y) 0.04 (general), <0.025 (crevice).

1.2Mn. Stronger than commercially pure grade—used in tanks and heat exchangers.

Higher strength usage—i.e., chemical tanks and pressure vessels.

4.5Cu/1.5 Mg. Commonly used engineering alloy used in aerospace applications. Al-Li alloys, higher strength to weight ratio than 2024 alloys—use in aircraft fuselages. These alloys are weldable but can suffer from SCC. 7Si. Heat treatable to higher strength—general marine usage. 356

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