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Copper Zirconium C15000, RWMA Class 1, AWS J1.3


Copper Zirconium is an excellent resistance welding material with very high softening temperatures. A small addition of zirconium to copper improves resistance to softening and resists deformation at high temperatures where normal copper would soften rapidly. Copper Zirconium is used as an RWMA Class 1 electrode material to minimize sticking when resistance spot welding galvanized/coated materials.

Chemical Compositions of RWMA Materials   Group A - Copper Base Alloys
RWMA Class UNS Number Description Cu¹ Fe W Cd Co Ni Cr Si Be Pb Zr Al
1 C15000 Zirconium Copper 99.80% min - - - - - - - - - 0.10-0.20% -


Typical usages of RWMA Class 1 Copper Alloy: C15000 is recommended for spot welding of coated steels and high conductivity materials, excluding copper and silver.





Axial Conductors

Back-up Electrodes


Caps & Shanks

Casting Wheels

Centrifugal Casting Molds

Circuit Breaker Parts

Collector Connector

Collector Housing

Connector Bar


Connection Lead Bar

Continuous Casting Molds

Cross Wire Welding Electrodes & Components

Damper Ring/Fingers

Dies & Fixtures

Electrode Holders & Adaptors

Electrical & Mechanical Power Components

End Rings & Rotor Bar

Flash & Butt Welding Dies

Flexible Connector

Joining Components

Lead Conductor Bar

Neutral Bus Bar

Nut & Stud Welding Electrodes

Power Generation Products

Power Semiconductor Bases

Resistance Welding Electrodes

Rotor Coil Bar

Seam Weld Wheels

Series Loop Segment

Slip Rings


Slot Wedge

Snap Rings

Special Nipple

Spot Welding Electrodes

Terminal Box Connectors

Transmission Devices

Threaded Electrodes

Water Clip

Welding Arms

Welding Blocks

Welding Connectors

Welding Platens




Item Name: Copper Zirconium Alloy C15000
RWMA (Resistance Welding Manufacturing Alliance) Class: Class 1
Principal Element: Cu, Zr
Minimum Hardness Rockwell (up to 1" dia.): HRB 65
Minimum Electrical Conductivity (% IACS): 80
Metal Stock Availability: Stocked in mill form or precision cut to your specifications.
Shape: Bar
Length for Round, Hexagon, Square, Octagon, Rectangle, Special Shapes: All sizes in standard lengths up to 12 ft
Special Sizes
Diameter for Round, Hexagon, Square, Octagon, Rectangle, Special Shapes: 1/8 to 8 1/8 in
Special Sizes
Thickness for Plate: 1/8 to 8 in
Special Sizes
ISO Certification: 9001:2015 (Registration # 10002745 QM15 Valid until 2024-08-21)
Reports: Certification of Compliance
Chemical Analysis
Final Inspection
Material Test Reports
Mechanical and Physical Testing: Elongation
Grain Size
Nondestructive Testing: Chemical Analysis
Liquid Penetrant
Alloy Applications Cross Reference Chart C15000 C18150 C18000 C18200 C17510 C17200 C15760
Axial Conductors X            
Back-up Electrodes X X X X X X X
Bushings X X X X X    
Caps & Shank X X X X X X X
Casting Wheels X X   X      
Casting Wheels and Dam Blocks     X   X X  
Centrifugal Casting Mold X X X X      
Circuit Breaker Parts X X   X     X
Collector Connector X X   X       
Collector Housing X X   X      
Connector Bar X X   X      
Connectors X X X X X   X
Connection Lead Bar X X   X      
Continuous Casting Molds X X X X X X  
Cross Wire Welding Electrodes & Components X X X X X X X
Damper Ring/Finger X X X X      
Dies & Fixtures X X X X X X  
Die Casting Pistons     X   X X  
Die Casting Plunger Tips     X   X X  
Electrode Holders & Adaptors X X X X X X  
Electrical & Mechanical Power Components X X X X X X X
Flash & Butt Welding Dies X X X X X X X
Flexible Connector X X   X      
Heat Flux Components X X X X X   X
Injection Blow Molds & Dies   X X X X X  
Joining Components X   X   X X X
Lead Conductor Bar X X   X      
Motor End Rings X X X X X    
Neutral Bus Bar X X   X      
Non-Sparking Applications   X X X X X  
Nut & Stud Welding Electrodes X X X X X X  
Performance Engine Components     X   X X  
Permanent Molds     X   X X X
Power Generation Products X X X X      
Power Semiconductor Bases X X   X      
Resistance Welding Electrodes X X X X X X  
Rotor Coil Bar X X   X      
Seam Weld Wheels X X X X X X  
Series Loop Segment X X   X      
Shafts X X X X X X  
Slip Rings X X   X      
Slot Wedge X X X X      
Snap Rings X X   X      
Special Nipple X X   X      
Terminal Box Connectors X X   X      
Threaded Electrodes X X X X X X  
Transmission Devices X X   X     X
Water Clip X X   X      
Wear Plates           X  
Welding Arms X X X X X X  
Welding Blocks X   X   X X  
Welding Connectors X X X X X X  
Welding Platens X X X X X X  

NOTE: C15000 Copper Zirconium and C18150 Copper Chromium Zirconium are both good replacements for C16200 Copper Cadmium. C15000 Copper Zirconium is a good replacement because of its excellent thermal and electrical conductivity while offering moderate strength. C15000 strength properties are developed through cold working (similar to C16200) whereas C18150 strength properties are developed primarily from heat treating (precipitation hardening), which is an advantage for large parts.