Copper Alloys

RWMA Copper Alloys

Material CDA #RWMA ClassCompositionDensity gr/ccDensity lb/in3Rockwell HardnessThermal ConductivityElectrical ConductivityUltimate Tensile Strength0.2% Yield Strength
Note: “typical” values listed – Not Material Specifications www.resistanceweldsupplies.com
C11000 --- Pure Copper 8.94 0.323 34 F 229 Btu / hr.ft.F 100% IACS 40,000 psi ---
C15000 1 Cu / Zr 8.89 0.321 70 B 212 Btu / hr.ft.F 90% IACS 66,000 psi 56,000 psi
C16200 1 Cu / Cd 8.89 0.321 70 B 198 Btu / hr.ft.F 90% IACS 65,000 psi 54,000 psi
C18200 2 Cu / Cr 8.89 0.321 83 B 187 Btu / hr.ft.F 85% IACS 75,000 psi 70,000 psi
C18150 2 Cu / Cr / Zr 8.89 0.321 82 B 187 Btu / hr.ft.F 74% IACS 81,000 psi 72,000 psi
C18000 3 Cu / Ni / Si / Cr 8.71 0.315 94 B 125 Btu / hr.ft.F 48% IACS 100,000 psi 75,000 psi
C17510 3 Cu / Ni / Be 8.75 0.316 100 B 113 Btu / hr.ft.F 48% IACS 110,000 psi 95,000 psi
C17200 4 Cu / Be 8.25 0.298 38 C 75 Btu / hr.ft.F 22% IACS 170,000 psi 150,000 psi
C15725 20 Cu / AL₂O₃ 8.86 0.32 73 B 199 Btu / hr.ft.F 87% IACS 75,000 psi 69,000 psi
C15760 20 Cu / AL₂O₃ 8.81 0.318 82 B 186 Btu / hr.ft.F 78% IACS 83,000 psi 79,000 psi
 

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RWMA Class 1

Also Known as: Tuffaloy 88, CMW 28, CuZr, and CuCd.

ZIRCONIUM-COPPER, suited to welding aluminum & magnesium alloys, coated materials, and brass & bronze.

Class 1: alloy is superior to pure copper as an electrode material and is recommended as a general-purpose material for resistance welding use. It may be used for spot welding electrodes, seam welding wheels and welding fixture components. It is not heat treatable. 

RWMA Class 2 

CHROMIUM-COPPER, suited to welding cold- and hot-rolled steels, stainless steel, and low conductivity brasses and bronzes.

Also Known as: CMW 3, CMW 328, Mallory 3, Tuffaloy 77, and Tuffaloy Z, CuCr, and CuCrZr.

Class 2: alloy is a superior resistance welding electrode material, recommended for high-production operations. It's used for welding electrodes, projection welding dies, seam welding shafts and bearings, flash and butt welding dies, and current-carrying structural components. Available in forms for use as welding gun arms, welding platens and secondary-circuit structural members. It is heat treatable.

ZIRCONIUM-CHROMIUM-COPPER is suited to welding galvanized steel & other metallic-coated steel. This is a specially heat-treated alloy, which meets the minimum electrical conductivity and hardness specifications of Class 2 alloy.

RWMA Class 3

Also Known as: CMW 100, CMW 353, Mallory 100, Tuffaloy 55, Tuffaloy 55A, CuNiSiCr, and CuNiBe.

BERYLLIUM-NICKEL-COPPER and NICKEL-COPPER are suited to welding steels having high electrical resistance, such as stainless steel.

Class 3: alloy is recommended for projection welding dies, and flash and butt-welding dies. With its higher strength it is also used on highly current-carrying parts such as electrode shanks and heavy-duty electrode holders. It is heat treatable.

RWMA Class 4

Also Known as: Tuffaloy 44, CMW 73, and CuBe.

BERYLLIUM-COPPER has extremely high hardness, and is recommended for projection, flash and butt-welding dies. It has lower conductivity than Class 3 alloy but it is harder and more wear resistant. It should be considered where there is concern with high-pressure density and severe wear, but where heating, due to its low conductivity, is no excessive.

It is used frequently in the form of inserts, die facings, and seam welder bushings. It is available in the annealed condition, which is more readily machined, and then subsequently heat-treated.

RWMA Class 20

Also Known as: Elkaloy 20 and CuAL₂O₃

COPPER-ALUMINUM OXIDE has exceptional resistance to deformation when welding and it is highly recommended for weld caps when welding coated and galvanized steels. It allows a stable start-up and generally outlasts other cap material when welding parameters are not carefully controlled.

Rectangular Bar - Class 1, 2, & 3

 
SIZEWEIGHT
1/4" x 1/2"  0.48 LBS/FT 
1/4" x 3/4"  0.73 LBS/FT 
1/4" x 1" 0.96 LBS/FT
1/4" x 1 1/4" 1.20 LBS/FT
1/4" x 1 1/2" 1.44 LBS/FT
1/4" x 2" 1.92 LBS/FT
3/8" x 5/8" 0.90 LBS/FT
3/8" x 3/4" 1.08 LBS/FT
3/8" x 1" 1.44 LBS/FT
3/8" x 1 1/2" 2.16 LBS/FT
3/8" x 2" 2.88 LBS/FT
1/2" x 3/4" 1.44 LBS/FT
1/2" x 1" 1.92 LBS/FT
1/2" x 1 1/4" 2.40 LBS/FT
1/2" x 1 1/2" 2.88 LBS/FT
1/2" x 2" 3.84 LBS/FT
1/2" x 2 1/2" 4.83 LBS/FT
1/2" x 3" 5.81 LBS/FT
5/8" x 3/4" 1.80 LBS/FT
5/8" x 1" 2.40 LBS/FT
5/8" x 1 1/2" 3.60 LBS/FT
5/8" x 2" 4.85 LBS/FT
5/8" x 3" 7.27 LBS/FT 
5/8" x 4" 9.60 LBS/FT
3/4" x 1" 2.88 LBS/FT
3/4" x 1 1/4" 3.64 LBS/FT
3/4" x 1 1/2" 4.32 LBS/FT
3/4" x 2" 5.72 LBS/FT
3/4" x 2 1/4" 6.48 LBS/FT
3/4" x 2 1/2" 7.20 LBS/FT
3/4" x 3" 8.64 LBS/FT
1" x 1 1/4" 4.85 LBS/FT
1" x 1 1/2" 5.76 LBS/FT
1" x 2" 7.68 LBS/FT
1" x 2 1/2" 9.70 LBS/FT
1" x 2 3/4" 10.56 LBS/FT
1" x 3" 11.55 LBS/FT
1 1/4" x 1 1/2" 7.25 LBS/FT
1 1/4" x 1 3/4" 8.40 LBS/FT
1 1/4" x 2" 9.60 LBS/FT
1 1/4" x 2 1/2" 12.06 LBS/FT
1 1/2" x 1 3/4" 10.09 LBS/FT
1 1/2" x 2" 11.60 LBS/FT
1 1/2" x 3" 17.28 LBS/FT
2" x 3 1/4" 25.15 LBS/FT
2" x 3 3/4" 29.05 LBS/FT

Round Bar - Class 1, 2, & 3

 
SIZEWEIGHT
1/8" 0.05 LBS/FT
3/16" 0.11 LBS/FT
1/4" 0.19 LBS/FT
5/16" 0.30 LBS/FT
3/8" 0.43 LBS/FT
1/2" 0.76 LBS/FT
9/16" 0.96 LBS/FT
5/8" 1.18 LBS/FT
3/4" 1.70 LBS/FT
7/8" 2.32 LBS/FT
1" 3.03 LBS/FT
1 1/8" 3.84 LBS/FT
1 1/4" 4.74 LBS/FT
1 3/8" 5.74 LBS/FT
1 1/2" 6.82 LBS/FT
1 5/8" 7.97 LBS/FT
1 3/4" 9.28 LBS/FT
2" 12.12 LBS/FT
2 1/8" 13.62 LBS/FT
2 1/4" 15.4 LBS/FT
2 1/2" 18.97 LBS/FT
2 3/4" 23.00 LBS/FT
3" 27.15 LBS/FT
3 1/4" 32.05 LBS/FT
3 1/2" 37.18 LBS/FT

Hex Bar - Class 1, 2, & 3

 
SIZEWEIGHT
3/8" 0.47 LBS/FT
1/2" 0.85 LBS/FT
5/8" 1.31 LBS/FT
3/4" 2.18 LBS/FT
7/8" 2.56 LBS/FT
1" 3.35 LBS/FT
1 1/8" 4.24 LBS/FT
1 1/4" 5.25 LBS/FT
1 1/2" 7.55 LBS/FT

Square Bar - Class 1, 2, & 3

 
SIZEWEIGHT
1/4" x 1/4" 0.24 LBS/FT
3/8" x 3/8" 0.54 LBS/FT
1/2" x 1/2" 0.96 LBS/FT
5/8" x 5/8" 1.56 LBS/FT
3/4" x 3/4" 2.16 LBS/FT
1" x 1" 3.84 LBS/FT
1 1/4" x 1 1/4" 6.00 LBS/FT
1 1/2" x 1 1/2" 8.64 LBS/FT
1 3/4" x 1 3/4" 11.83 LBS/FT
2" x 2" 15.46 LBS/FT