Introduction to alloy classification

These are alloys of copper with 5-12% aluminium, some having additions of iron, nickel, manganese and silicon, available in cast and wrought form. They are stronger than brasses or tin bronzes with better corrosion resistance due to a hard, adherent, protective alumina film (Al203). They have an attractive golden colour, with very little tarnishing with time.

Special alloy characteristics

The major use for aluminium bronzes is in seawater applications, such as:

For marine applications they meet exacting Def Stan (Defence Standard) specifications (previously Naval Engineering Standard - NES), and are widely used for MOD applications.

The durability and golden colour makes aluminium bronze an attractive proposition for architects, for example as cast upright balustrades for the Sackler Crossing in Kew Gardens, London. The alloy used for this project was CuAl8Fe3; the balustrades were polished to the required finish and waxed in situ.

Equivalent Specifications

Introduction to alloy classification

By composition these alloys are brasses but have picked up the bronze name because of their colours. Manganese bronze CuZn40Mn1Pb1 (CW720R) is a brass used for architectural applications where the manganese leads to the formation of an attractive chocolate brown colour.

The term 'architectural bronze' is sometimes applied to a leaded aluminium brass CuZn41Pb1Al (CW620N) which, due to the aluminium, develops an attractive golden lustre.

Special alloy characteristics

Like all brasses, this alloy combines longevity with an aesthetic appeal which improves with time and gives a feeling of luxury and prestige to any building both inside and out. It is available as profiles and rectangular bar and is used for window frames, cladding, doors and curtain walls. It is usually finished by waxing to maintain the appearance.

Equivalent Specifications

Introduction to alloy classification

Of the aluminium bronze alloys, the nickel aluminium bronze group is the most widely used. These alloys have high strength, corrosion, wear and galling resistance and have been adapted over time to optimise performance.

Special alloy characteristics

They can provide a combination of properties offering an economic alternative to other types of alloy systems, and their applications include landing gear bearings in commercial aircraft.

Equivalent Specifications

Introduction to alloy classification

This is an alloy of copper with 3% silicon and 1% manganese. It has a good combination of strength, ductility, corrosion resistance and weldability.

Special alloy characteristics

It is used in architectural applications such as:

The alloy is a firm favourite with sculptors and metal smiths because of its workability, longevity and attractive golden bronze colour.

Silicon bronze is also widely used for marine hardware and fasteners such as bolts, clamps, screws, nuts, rivets and U bolts.

Equivalent Specifications

Introduction to alloy classification

These alloys of copper and tin were the first metallic alloys to be developed by mankind, about four thousand years ago, and were used for coins, weapons, tools, jewellery and ornaments. They revolutionised the way man lived leading to archaeologists naming the period the Bronze Age.

In modern times wrought bronzes have been developed with 4-8% tin which are harder, stronger, and stiffer than wrought brasses and, in strip and wire form, are produced with a combination of high yield strength and good corrosion resistance. The addition of small amounts (0.01-0.45%) of phosphorus increases the hardness, fatigue resistance and wear resistance, leading to their use in applications such as springs, bellows, flexible tubing, fasteners, masonry fixings, shafts, valve spindles, gears and bearings.

Special alloy characteristics

Alloying elements with copper, in this case tin and phosphorus, can result in lower electrical conductivity compared to pure copper. The most widely used phosphor bronze for electrical purposes contains 0.2% phosphorus and 5% tin and has an electrical conductivity of 15% IACS (Copper is 100% IACS). However, the combination of high yield strength, which gives a good contact force, and good corrosion resistance make this bronze ideal for a wide range of small electrical connectors, switches, current carrying springs and rotor bars. These properties are retained at high operating temperatures.

Wrought leaded phosphor bronzes (3-4% lead) combine the above properties with outstanding machinability and significant self-lubrication, self-seating and alignment in bearing applications and excellent resistance to seizure. Applications include thrust washers, bearing bushes, cams, clutch plates, intricate machined fasteners and other turned parts, clock and instrument parts, gears, pinions, pump and valve spindles and engraved components.

Special alloy characteristics

Phosphor bronzes with higher tin contents are available in all the common cast forms. They have up to 13% tin and 2.5% lead (for machinability) and nickel (for strength and hardness) and are widely used for bearings and gears.

Equivalent Specifications

Introduction to alloy classification

The addition of nickel to copper improves strength and corrosion resistance without reducing the good ductility. Copper-nickel alloys have excellent resistance to marine corrosion and biofouling. The two main alloys are 90/10 (90% copper, 10% nickel) and 70/30 (70% copper, 30% nickel) [link to Def Stan 780. The 70/30 is the stronger and has greater resistance to seawater flow, but the 90/10 will provide good service for most applications and, being less expensive, tends to be more widely used. Both alloys contain small but important additions of iron and manganese which have been chosen to provide the best combination of resistance to flowing seawater and to overall corrosion.

Special alloy characteristics

Copper-nickel alloys are widely used for marine applications due to their excellent resistance to seawater corrosion, high inherent resistance to biofouling and ease of fabrication.. They have provided reliable service for several decades whilst offering effective solutions to todays technological challenges.

Applications

Equivalent Specifications

Introduction to alloy classification

Nickel has been used in alloys that date back to the dawn of civilization. Nickel in elemental form or alloyed with other metals and materials has made significant contributions to our present-day society and promises to continue to supply materials for an even more demanding future.

Nickel is a versatile element and will alloy with most metals. Complete solid solubility exists between nickel and copper. Wide solubility ranges between iron, chromium, and nickel make possible many alloy combinations.

Introduction to alloy classification

These nickel chromium base alloys are used extensively in applications where heat resistance and/or corrosion resistance is required. In some members of the group, where conditions are less demanding, some nickel is replaced by iron to decrease the overall cost.

Metals fail at high temperatures by both oxidation (scaling) and through a loss in strength. Alloys in this class are designed to resist failure from both of these mechanisms. Nickel alloys are not suitable for high temperature sulphur rich environments.

Where corrosion resistance is significant, molybdenum is used as an alloying addition in nickel chromium based alloys.

Special alloy characteristics

This group of alloys are frequently sold under trade name specifications but most are listed in the Unified Numbering System.

The more recent nickel chromium base alloys in these groups also have a wide range of ancillary elements added to give special properties - some of these can be quite complicated and require very close control over composition and heat treatment.

Equivalent Specifications

Introduction to alloy classification

These nickel copper alloys contain nickel with copper and small amounts of iron and manganese. A typical nickel copper alloy is the 400 grade (UNS N04400) or K-500 (UNS N05500). Nickel 400 contains 63% nickel minimum, 28-34% copper, and a maximum of 2% manganese and 2.5% iron. There are also a small number of impurities kept at limited values to ensure the metal's properties are not harmed.

Special alloy characteristics

These nickel copper alloys are used where a higher strength is required compared to pure nickel. Nickel copper alloys have a wider range of environments where they resist corrosion but in some specialised applications, such as strong alkali contaminant, nickel or commercially pure nickel would be superior.

Nickel copper alloys find wide application in oil refining and marine applications where long corrosion-free life is required. Because of good thermal conductivity of nickel copper alloys, they are frequently are used for heat exchangers where sea water is one of the fluids concerned.

Equivalent Specifications

Introduction to alloy classification

Designed to give engineers more options, the Elite Alloys are a range of advanced copper-based alloys that have been developed by Copper Alloys for extreme applications. To qualify, and Elite Alloys has to be peerless. It has to possess a combination of characteristics currently offered by no other material.

Introduction to alloy classification

These highly corrosion resistant alloys are strengthened by both solid solution and precipitation mechanisms. Applying deep metallurgical understanding and advanced process techniques, the Elite alloys possess material properties that are unavailable elsewhere.

This suite of Elite Marine Alloys has a wide spectrum of mechanical properties ensuring a range of demanding applications can be satisfied. These highly corrosion resistant alloys are also available with extreme fracture toughness properties, combined with high strength, through to extreme tensile strength and hardness.

The extremely low general corrosion rate and immunity to preferential phase attack make these materials ideal for critical, long-term marine applications and significantly out-perform conventional materials such as nickel aluminium bronze and conventional cupro-nickel alloys.

Special alloy characteristics

These industry-leading alloys are the result of decades of research and an advanced manufacturing capability combined with metallurgical expertise, allowing us to produce a range of wrought products to 5,000kgs piece-weight.

These materials are available as raw material (proof machined bar stock, forgings, plates) or finished machined components.

Full traceability and full certification in accordance with EN 10204 3.1 are provided as standard. 3.2 Certification is available upon request.

Equivalent Specifications

Introduction to alloy classification

Elite Thermal Alloys benefit from a unique combination of properties, making them the ideal material choice for equipment requiring high strength and high conductivity.

The Elite Thermal Alloys benefit from a unique combination of properties make it the ideal material choice for equipment requiring high strength and high conductivity.

The Elite Thermal Alloys have been designed by the renowned metallurgists at Copper Alloys Ltd. to give an advantage to engineers working in extreme environments.

Specifying Elite Thermal Alloys will reduce reliance on toxic high cost materials such as beryllium copper.

Special alloy characteristics

Performance can be improved and service life extended by using these alloys, resulting in significant cost advantages in oilfield exploration and processing, moulding applications, fine measurement tooling and other applications where high wear resistance and conductivity are important.

The Elite Thermal Alloys present engineers with design flexibility.

Manufactured in three tempers of increasing strength, it is also possible to customise the alloys to specific applications.

Equivalent Specifications

Introduction to alloy classification

Copper Alloys Ltd has developed a range of materials optimised for use in extreme and aggressive bearing applications. Harnessing the super strength generated from highly refined process technology, including the unique Microfine® method of manufacture.

This unique combination allows previously cast only alloys to be manufactured with a fine grain structure, which facilitates the application of mechanical work to be introduced in order to push the mechanical properties to the extreme.

Introduction to alloy classification

Based on the nominal composition CuPb15Sn8P, this is a Leaded Phosphor Bronze conforming to UNS C93800 and supplied in three grades SL340 (hard wearing), SL300 (medium wearing) and SL240 (soft wearing) with increasing self-lubrication and reducing yield strength.

Special alloy characteristics

Equivalent Specifications

Introduction to alloy classification

Based on the nominal composition CuSn8P, this is a Phosphor Bronze conforming to UNS C52100 and supplied in three grades LF600 (hard wearing), LF450 (medium wearing) and LF400 (soft wearing) with increasing tensile strength and reducing friction.

Special alloy characteristics

Equivalent Specifications