Superior Strength Precipitation Hardening Copper Nickel Silicon Alloy - Trojan

Trojan is the ultimate superior strength precipitation hardening copper nickel silicon alloy. Based on the same alloying system as its sister alloy Colsibro®, Trojan has been specifically developed as a higher strength material with a similar blend of physical properties. The exceptional mechanical strength of Trojan, incorporated with its high electrical and thermal conductivity, a good corrosion resistance and an excellent wear resistance has opened up markets in safety- critical engineering fields where beryllium copper was once the only option. The additional strength has also extended the application areas served by conventional copper nickel silicon alloys.

Trojan is a high copper alloy with tiny additions of silicon and nickel that combine to increase the hardness, strength and wear resistance of the material, while retaining a number of the physical benefits of copper itself. As with other copper nickel silicon alloys, Trojan derives its excellent strength characteristics via a combination of cold work and an exceptionally dispersed Ni2Si precipitate that is responsible for hardening the metal matrix. Columbia Metals stocks Trojan in the completely heat treated condition in order to maximize the material’s mechanical strength. This allows Trojan to offer strength levels comparable with a number of bolting, alloy and stainless steels. The proof strength is almost 90% that of the UTS, while retaining a high hardness level and good ductility. These attributes, integrated with high anti-friction properties and exceptional wear resistance, offer extremely good bearing properties under high loading.

Trojan offers a corrosion resistance that is categorized as extremely good in both industrial and marine environments. Like Colsibro®, it provides a high corrosion resistance in sea water and fresh water, a freedom from hydrogen embrittlement and an excellent resistance to wet sulfurous atmospheres. Incorporated with its low magnetic permeability and exceptional cryogenic properties, this allows Trojan to be an exceptional choice for more challenging marine and industrial applications including subsea connectors and non-magnetic instrumentation both below and above the waterline.

Trojan has about 1% more nickel than Colsibro® but its high copper content is sufficient to guarantee that it maintains an impressive electrical and thermal conductivity value. The high thermal conductivity integrated with a resistance to softening up to ~300 °C, its inherent wear resistance and exceptional mechanical strength levels guarantee that Trojan is the ideal selection for demanding engine bearings along with standard uses such as valve seats, valve guides and gears. The high strength and conductivity values are also vital for the specification of Trojan in several other components such as electrical connectors contact blades, slip rings and other current-carrying components, plugs and sockets, springs, rotary contacts, heavy duty switchgear and several other electrical accessories.

It is possible to readily fabricate Trojan by machining and cold or hot forming. It can be soldered, brazed and the welded by standard TIG and MIG methods and is also resistance weldable. This exceptional combination of properties guarantees that Trojan continues to be the superior choice, both technically and also economically, compared with a number of alternative materials. Successful application areas include bearing cages, bushes, slip rings, high strength fasteners, mechanical seals, valve bodies, short circuit rings, thrust pads, resistance welding wheels and electrodes, masonry fixings, spark-resistant safety tools and flash butt welding dies.

  • Proof Strength 90% OF UTS
  • Low magnetic permeability
  • High thermal conductivity
  • Readily machinable
  • Spark resistant
  • Very high wear resistance
  • Good electrical conductivity
  • High corrosion resistance
  • Exceptional Mechanical Strength

Technical Data

Nominal Composition (%)

Cu Ni Si
Rem 2.6 - 4.5 0.8 - 1.3


Mechanical Properties (specification minima)

  ≤30 mm dia 30 ≤ 60 mm dia 60 ≤ 80 mm dia
Ultimate Tensile Strength (N/mm2) 800 690 690
0.2% Proof Strength (N/mm2) 750 570 570
Elongation (%) 10 10 10
Hardness (HB) 200 200 190


Typical Physical Properties

. .
Density (g/cm3) 8.8
Melting Range (°C) 1060 - 1085
Thermal conductivity (20 °C; W/m°K) 159
Coeff. Thermal Exp. (0-400 °C; m/m°K x 10-6) 16.0
Electrical Conductivity (IACS) 30
Magnetic Permeability ~1.001


Round Bar Weight and Stock Sizes

Diameter Weight Diameter Weight Diameter Weight
ins kg/ft kg/m ins kg/ft kg/m ins kg/ft kg/m
2 mm 0.01 0.03 0.625 0.52 1.70 1.500 2.99 9.81
0.125 0.02 0.07 0.750 0.75 2.45 1.625 3.51 11.51
0.250 0.08 0.27 0.875 1.02 3.34 1.750 4.07 13.35
0.375 0.19 0.61 1.000 1.33 4.36 2.000 5.32 17.44
10 mm 0.21 0.68 1.125 1.68 5.52 2.250 6.73 22.07
0.500 0.33 1.09 1.250 2.08 6.81 2.500 8.30 27.24
0.563 0.42 1.38 1.375 2.51 8.24 65 mm 8.70 28.55


NB Weight data for guidance only.

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