Cast Copper Alloy Information

This page is dedicated to all things related to the Cast Copper Bronzes that we produce.

Bronzes

Bronzes are copper alloys in which the major alloying addition is neither zinc nor nickel. Tin (Cu-Sn-P) bronzes (C50100 to C52480), also commonly referred to as phosphor bronzes, have superb spring qualities, high fatigue resistance,excellent formability and solderability, and high corrosion resistance. They are primarily produced as strip for electrical products. Other uses include corrosion-resistant bellows, diaphragms, and spring washers. Leaded (Cu-Sn-P-Pb) tin or phosphor bronzes (C53400 and C54400) combine high strength and fatigue resistance with good machinability, high wear resistance, and excellent corrosion resistance, especially in seawater. They are frequently used for sleeve bearings, thrust washers, cam followers, and similar parts. Leaded tin bronze bearings resist pounding, but should be used against hardened journals (300 to 400 HB min), and only in applications where reliable lubrication is assured. Aluminum (Cu-Al) bronzes (C60800 to C64210) are best known for their combination of high strength and excellent corrosion resistance. Their stress-corrosion fatigue resistance exceeds that of austenitic stainless steels. They are readily weldable, and can be machined or ground, although good lubrication and cooling are essential to obtain fine surface finishes. Aluminum bronzes containing less than about 9.5% Al are hardened through a combination of solid-solution strengthening, cold work, and the precipitation of an iron-rich phase. Tensile strengths range between 480 and 690 MPa (70 and 100 ksi), depending on composition and temper. High-aluminum alloys (9 to 11% Al), such as C63000 and C63020, can be quenched and tempered much like steels to produce tensile strengths higher than 1000 MPa (145ksi). Aluminum bronzes have a very wide range of applications. Common uses include marine hardware, shafts, and pump and valve components for handling seawater, sour mine waters, nonoxidizing acids, and industrial process fluids. The good wear resistance of the alloys makes them excellent choices for heavy-duty sleeve bearings and machine-tool ways. Because the aluminum reduces density in addition to raising strength, these bronzes have relatively high strength-to-weight ratios. This explains why nickel-aluminum bronze (C63020) is sometimes substituted for beryllium-copper in aircraft landing-gear bearings. Silicon (Cu-Si) bronzes (C64700 to C66100) resemble the lower-aluminum bronzes in mechanical properties, having nominal tensile strengths up to about 690 MPa (100 ksi). The alloys exhibit the good corrosion resistance characteristic of all copper metals, although their resistance to SCC is somewhat lower than that of the aluminum bronzes. Silicon bronzes are produced in relatively low volumes for products such as hydraulic fluid lines, high-strength fasteners, wear plates, and marine and pole-line hardware. The alloys have excellent weldability, and are commonly used as welding filler wire.

Alloying Agents - Sub Divisions of Bronze

Although there are exceptions, bronzes are generally classified by their major alloying element or elements.

Brasses are now broken down into sub-categories aligned to their alloying elements. These Bronzes contain specified quantities of Lead (Pb), Tin (Sn), Manganese (Mn), Silicon (Si), Bismuth (Bi) and Selenium (Se). There are five subfamilies of bronzes among the cast copper aUoys::

In the sections that follow (which you expand or collapse by clicking), we provide a full listing of the alloys available, we provide the UNS designations and the common equivalents in other designations.

Tin BronzesClick to expand/close

These Bronzes have element combinations of Copper & Tin or Copper, Tin & Phosphor. [Cu-Zn-Sn-Pb(90-96%Cu)]

Tin bronze alloys such as C90300 are typically found in gear and high-strength bushing and bearing applications where high strength, low speeds, and heavy loads are present. Other high-strength applications for these alloys are pump impellers, piston rings, steam fittings, and valve bodies. C903 tin bronze castings are utilized in movable bridge components, turntables for bridges, and other structures for fixed and expansion bearings with slow or intermittent movement and heavy loads.

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Leaded Tin BronzesClick to expand/close

These Brasses have either elment combinations of Copper, Tin & Zinc or Copper, Tin, Zinc & Lead. [Cu-Zn-Sn-Pb(75-89%Cu)]

Semi Red Brass has higher Zinc content than Red Brass which reduces corrosion resistance, lowers input costs but does not impact strength. They still retain outstanding aquaeous corrosion resistance and hence are used in plumbing applications. Lead weakens all of these bearing alloys but imparts the ability to tolerate intenupted lubrication. Lead also allows dirt particles to become embeded harmlessly in the bearing's surface, thereby protecting the journal. This is important in off-highway equipment.

High-Leaded Tin BronzesClick to expand/close

High-Leaded Tin Bronzes have element combinations of Copper, Zinc & Tin with high % of Lead. [Cu-Sn-Zn-Pb]

Leaded tin bronze alloys are free cutting and retain favourable thermal conductivity and good lubricity due to the presence of lead. Alloy C93200, also termed C932, Bearing Bronze is considered this alloy family’s workhorse and is widely used in many bearing applications

Nickel-Tin BronzesClick to expand/close

The nickel-tin bronzes are characterized by moderate strength and very good corrosion resistance, especially in aqueous media. One member of this family, C94700, can be age-hardened to typical tensile strengths as high as 510 MPa (74 ksi ). Wear resistance is particularly good. As with the tin bronzes, nickel-tin bronzes are used for bearings, but these versatile alloys more frequently find application as valve and pump components, gears, shifter forks and circuit breaker parts.

The nickel tin bronzes can be heat treated to produce precipitation hardening. The precipitating phase is a copper-tin intermetallic compound which forns during slow cooling in the mold or during a subsequent aging treatment. Lead is detrimental to the hardening process to the extent that leaded nickel-tin bronzes are not considered heat-treatable.

Aluminium BronzesClick to expand/close

These Bronzes have either elment combinations of Copper, Aluminum & Iron [Cu-Al-Fe] or Copper, Aluminum, Iron & Nickel [Cu-Al-Fe-Ni]

Aluminum bronze is the highest strength standard copper-based alloy. All of the aluminum bronzes can be heat treated, further increasing tensile strengths. Aluminium bronzes are alloys of copper and aluminium. The content of aluminium ranges mostly between 5% and 11%. Iron, nickel, manganese and silicon are sometimes added. They have higher strength and corrosion resistance than other bronzes, especially in marine environment, and have low reactivity to sulphur compounds. The alloys are readily fabricated and welded and have been used to produce some of the largest nonferrous cast structures in existence. Aluminum bronze bearings are used in heavily loaded applications.

These alloys exhibit some of the most interesting metallurgical structures found among all commercial alloys. Aluminum bronzes containing less than about 9.25% aluminum consist mainly of the face-centered cubic alpha structure, although iron and nickel-rich phases, which contribute strength, will also be present. Higher aluminum concentrations, and/or the addition of silicon or manganese, lead to the formation of the beta phase. Beta transforms into a variety of secondary phases as the casting cools. Standard alloy compositions are carefully balanced to ensure that the resulting complex structures are beneficial to the bronzes' mechanical properties.


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