C18150 Class 2 Chromium Zirconium Copper

Class 2 Chromium zirconium Class 2 Alloy C18150 has good thermal and electrical conductivity. More than 400 varieties of these copper alloys are available, but C18150 is highly preferred since it has high strength and wear resistance at elevated temperatures. C18150 is used extensively for cap-style resistance welding electrodes. It can provide less sticking and resist deformation for much longer than its copper-chrome counterpart in some specific situations. 

The chemical composition of C18150 is 1% chromium, 98.85% copper, and 0.15% zirconium. The addition of Zirconium to chromium copper improves creep resistance at high operating temperatures and reduces sticking of electrodes to the work during spot welding of galvanized or coated materials. The physical copper properties of C18150 include a density of 8.89 grams per cubic centimeter.

Buy Now

Applications of Chromium Zirconium

Chromium zirconium has some of the most extensive applications. Here are just a few examples of the applications of this metal type:

  • Back-up electrodes
  • Nut & stud welding electrodes
  • Caps & shanks
  • Circuit breaker parts
  • Collector connector, collector housing, connector bar, connectors, and connection lead bars
  • Cross wire welding electrodes & components
  • Electrode holders & adaptors
  • Flash & butt welding dies
  • Power generation products
  • Resistance welding electrodes
  • Spot welding electrodes
  • Transmission devices
  • Welding arms, connectors, and platens. 

C18150 MSDS

Typical Uses of Chromium Zirconium

Stress Relaxation

Chromium zirconium is a unique copper alloy that’s able to decrease stress under constant strain. It’s typically used with steel bolts in turbine casting, which must be straightened and typed. 


Machining includes a variety of processes in which a raw piece of material is cut into a desired final shape and size by a controlled material-removal process. The machinability rating of C18150 is 30% which is moderate. The use of a cutting tool with a chip breaker is recommended. 

Material Properties of C18150

The C18150 copper alloy has a combination of properties as below:

  • Tensile strength: 220-540 N/mm2
  • 0.2% Proof strength: 100-440 N/mm2
  • % Elongation: 35-5
  • Hardness (HV): 55-175
  • Electrical conductivity: 80% IACS
  • Thermal conductivity: 300 W/moC (compared to copper 394 W/moC)

Fabrication Properties

The most common fabrication properties of C18150 are bending, cold heading, and machining. The machinability rating of C18150 is 20. The fabrication properties of C18150 Copper can be categorized as either good, not recommended, fair, or excellent. The properties are as follows:

  • Good for:
    • Soldering
    • Brazing
    • Gas shielded arc welding
  • Excellent for: 
    • Capacity for being cold worked
  • Fair for:
    • Butt welding
  • Not recommended for:
    • Oxyacetylene welding
    • Coated metal arc welding
    • Spot Welding 
    • Seam Welding

C18150 chromium zirconium copper is a unique copper with the addition of zirconium. It is readily available across North America and has extensive uses.

Health Hazard Information for Users of Chromium Copper C18200 and Chromium Zirconium Copper 18150 Alloys (MSDS)