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Copper Nickel Silicon Chromium C18000, RWMA Class 3, AWS J1.3 


Copper Nickel Silicon Chromium is a very hard heat treatable copper with moderate electrical conductivity. C18000 is utilized when a combination of very good mechanical strength along with moderate electrical and thermal electrical conductivity is required. It offers excellent value for the properties and is a high-value substitute for C17500 and C17510 in many applications as it meets RWMS Class 3 Specifications. Refer to Cadi MOLD-MOR 1® for mold applications.





Chemical Compositions of RWMA Materials   Group A - Copper Base Alloys

RWMA Class

UNS Number








Nickel Silicon Chromium Copper


1.8 – 3.0%

0.1 – 0.8%

0.4 – 0.8%

Cu: Copper

Ni: Nickel

Cr: Chromium

Si: Silicon


Typical usages of RWMA Class 3 copper alloy: C18000 is recommended for spot and seam welding of high resistance alloys such as stainless steel. Other uses include flash welding dies, backup bars, and projection welding electrodes.




Back-up Electrodes


Caps & Shanks

Casting Wheels & (Forged) Dam Blocks

Continuous Casting Molds

Cross Wire Welding Electrodes & Components

Dies & Fixtures

Electrode Holders and Adaptors

Electrical & Mechanical Power Components

End Rings & Rotor Bar

Flash & Butt Welding Dies

Injection Blow Molds & Dies

Joining Components

Nut & Stud Welding Electrodes

Permanent Molds

Pistons (Die Casting)

Plunger Tips (Die Casting)

Resistance Welding Electrodes

Seam Weld Wheels


Spot Welding Electrodes

Sputtering Target Backing Plates

Threaded Electrodes

Welding Arms

Welding Blocks

Welding Connectors

Welding Platens

Brake Drums for Paper Rolls


Item Name: Copper Nickel Silicon Chromium (Be Free) Alloy C18000
RWMA (Resistance Welding Manufacturing Alliance) Class: Class 3
Principal Element: Cu, Ni, Si, Cr
Minimum Hardness Rockwell (up to 1" dia.): HRB 90
Minimum Electrical Conductivity (% IACS): 45
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 15 1/8 in
Special Sizes
Thickness for Plate: 1/8 to 10 in
Special Sizes


Click here for information on Rolled and Forged Plate


Quality Assurance


Quality Policy: Cadi Company Inc. is dedicated to world-class excellence. Our commitment is to continually achieve the highest standards required to meet our customer’s needs.  Cadi is committed to a policy of continuous improvement within all areas of the organization through customer communication, by means of quality planning and review, as well as employee training and participation to achieve the Cadi commitment goal of 100% in quality, effectiveness, and customer satisfaction.


Quality Objectives: Cadi Company, Inc. is committed to the development and implementation of the ISO Quality Management System. We pledge that through the efforts of all our employees working together as a team, we will continually strive to be a leader (in our markets) in satisfying our customers’ needs with regard to service, performance, and competitive pricing. Cadi shall maintain global and domestic sources to provide quality products as required by our customers. Cadi will provide our customers with the highest level of satisfaction by achieving the goal of 100% in the areas of product quality and on-time delivery performance.


Cadi Company is committed to providing goods and services that meet or exceed our customer’s requirements and expectations. It is our firm belief that this dedication to the highest standards is the cornerstone of our existence.

  • We have the equipment and processes to guarantee the quality of the products we manufacture.
  • We continually upgrade our equipment and have ongoing training company-wide.
  • Each order undergoes stringent Quality Assurance Processes to assure accuracy and precision to the client’s specifications and is verified throughout the manufacturing cycle with scheduled quality assurance audits.
  • All material is subject to detailed physical tests where microstructures, tensile, yield strength, U.T. testing, eddy current conductivity, elongation, and hardness are measured and reported.
  • Climate-controlled inspection facility.
  •  We have a Metallurgical Engineer on-site for any technical questions.


To ensure Cadi follows rigorous quality and procedural protocols we are ISO 9001:2015 Certified and have been for over 18 years.


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 - - -
Sputtering Target Backing Plate   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 -


Other References For C18000: CuNiSiCr, Class 3 Copper, RWMA Class 3, Beryllium Free Copper, Performance Alloy, Corson Alloy, UNS C18000, CDA C18000, similar to CuNi2Si and C64700, Ampcoloy 940 (equivalent), Cupronickel, Cupro Nickel and Oxygen Free Copper.