Aluminum bronze - the high-end copper alloy

The “A” stands for aluminum bronze, and the number that follows represents the average hardness value measured in Brinell (HBW10/3000).

ALBROMET aluminum bronzes do not contain any hazardous substances that are on the REACH candidate list (SVHC list). The average lead content is < 0.02%, which is well below the critical value of < 0.05%. This means that the copper alloys are REACH and RoHS compliant. You can find more information here.

Due to its composition and excellent polishability, aluminum bronze reduces sliding friction between mating surfaces. Aluminum bronze and steel do not react chemically with each other and therefore do not form any compounds that could lead to adhesion. Their high hardness and strength also make them resistant to abrasion. If the hardness of the selected aluminum bronze is lower than that of the friction partner (e.g., steel), it is defined as the wear partner in the friction system. Aluminum bronze efficiently dissipates heat, which prevents the sliding surfaces from overheating. By dissipating heat, this also reduces the likelihood of damage caused by thermal stress during sliding friction between the sliding surfaces. Sufficient lubrication is required depending on the load. However, the emergency running properties of aluminum bronze are very good.

Aluminum bronzes are usually produced using traditional smelting processes and further processing of continuous cast billets in forges and pressing plants. ALBROMET sources its aluminum bronzes mainly in Europe and North America. Various dimensions of round, tubular and flat material are kept in stock. These are cut to size at ALBROMET at short notice.

Aluminum bronzes are generally highly recyclable, as copper and its alloys are among the most commonly recycled metals worldwide and can be remelted with virtually no loss of material. The recycling process requires significantly less energy than primary production, which substantially reduces the environmental footprint of aluminum bronze components over their entire life cycle. One challenge in recycling is the accurate sorting and identification of the various alloy types, as different aluminum bronzes contain varying levels of aluminum, nickel, iron, and manganese, which require specific processing. However, modern analytical techniques such as X-ray fluorescence analysis (XRF) enable rapid and precise alloy identification in the scrap metal trade, thereby ensuring that materials are sorted by type and recycled to a high standard. Since there is virtually no loss of quality when melting down aluminum bronze scrap, recycled alloys can in many cases be used directly in demanding technical applications such as plain bearings, guide bushings, and forming tools.

Aluminum bronzes are corrosion-resistant in alkaline media with a pH value of > 7. They are often used in applications involving alkaline solutions or alkaline media, such as in the chemical industry, in seawater environments or in applications with a high pH value. The addition of aluminum to copper alloys forms a protective oxide layer on their surface, which protects them from corrosion. This oxide layer is particularly stable and resistant, even in basic or alkaline environments. However, the resistance depends on the specific composition of the alloy, the temperature, the concentration of the basic solution and the duration of exposure.

In acidic media with a pH value between 7 and 4.5, aluminum bronzes exhibit good corrosion resistance.However, they can be sensitive to strong or oxidizing acids such as hydrochloric acid or sulphuric acid.The concentration of the acid plays an important role here.Higher temperatures increase reactivity and accelerate corrosion.The exact composition of the aluminum bronze alloy influences its corrosion resistance.

Aluminum bronzes have a high strength, which makes them robust and resistant to mechanical stress. Carbide tools are very suitable for machining aluminum bronzes. Diamond tools offer the best performance, especially for demanding machining operations. High-speed steel (HSS) tools can be used, but are less effective than carbide or diamond tools. Adequate cooling and lubrication during machining is essential. This helps to keep the tools cool, improve surface quality and extend tool life. With the right techniques and tools, precise and high-quality machining results can be achieved.