Copper Alloys


Colsibro® is a precipitation hardening copper nickel silicon that offers a remarkable blend of physical and mechanical attributes unrivalled by many other grades of copper alloy. It is widely specified for use in high performance automotive and motorsport engine components including valve guides, valve seats, gears and bushes. Its combination of high strength, corrosion resistance, high thermal and electrical conductivity, excellent wear resistance, spark resistance and good cryogenic properties has enabled Colsibro® to find a place in virtually every engineering field, from electrical to mechanical and automotive to marine.

Colsibro® is a high copper alloy with small additions of nickel and silicon, which combine to increase the strength, hardness and wear resistance of the material, while retaining many of the physical benefits of copper itself.

Related Specifications of Colsibro®

  • DTD498
  • C64700
  • C18000
  • CW111C
  • EN 12163
  • ASTM B411
  • 2.0855
  • CuNi2Si

Nominal Composition of Colsibro®

Cu rem, Ni 2.0%, Si 0.6%

Mechanical Properties of Colsibro®

Ultimate Tensile Strength (N/mm²) Proof Stress (N/mm²) Elongation (%) Hardness (HB)
550-640 430-590 10 155-180

Key Features of Colsibro®

  • Excellent corrosion resistance, surpassing many copper alloys, with complete freedom from stress corrosion
  • High strength and hardness
  • Very good wear resistance and bearing properties
  • Excellent thermal and electrical conductivities compared to most non-ferrous alloys
  • Outstanding cryogenic properties and an exceptionally low magnetic permeability
  • Complete freedom from hydrogen embrittlement
  • Spark resistance

Applications of Colsibro®

Automotive | Valve guides, valve seats, gears, rocker and little end bushes or internal combustion engines requiring extreme performance

Offshore & marine | Fasteners, valves, choke stems, down-hole tooling, cryogenic storage tanks and pump bodies

Electrical |  current-carrying electrical components such as slip rings, squirrel cages, springs, rotary switch contacts, contact blades, short-circuit rings and heavy duty switchgear

Other | Non-magnetic instrument components and spark-resistant safety tooling

Case Studies

Colsibro®: valve guides and valve seats
Colsibro®: motorcycle valve guides

Columbia Metals – a leading supplier of Colsibro®

With decades of experience and a huge range of stock, Columbia Metals is an industry leader in the supply of Colsibro® and other high quality specialist engineering alloys.

To buy or learn more about Colsibro® contact us now, or fill in the enquiry form on the right hand side and we will be in touch shortly.

  Related Specifications Mechanical Properties
Alloy Name BS UNS BS EN Others Ultimate Tensile Strength N/mm² Minimum Yield Strength N/mm² Elongation % Hardness HB  
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