Picking and Sizing your electrodes.

How to choose the right material for your resistance welding applcation and how to size properly size your electrodes.

This page was designed to help you pick the right* resistance welding electrode.

Below we will review electrode materials to help determine which is right for your application and how to choose.
We will discuss how to pick the right electrode tip profile and size for your project.
And we will help you pick the right size taper (4RW, 5RW, 6RW, 7RW) for your application based on expected force.

It is important to note, not all welding electrodes and metals are created equal. All of our proudcts are pressed and machined from virgin bar stock.

Electrode Material

There are over a dozen copper alloys used in modern day resistance welding. Many of these alloys are speicaly metals engineered to help weld different or difficult welding applications.

It's important to recognize that every welding application is different. Choosing the right alloy for your weld is imporant to repeatable resistance welding quality.
Our standard electrodes and caps are most commonly machined from RWMA Class 1, Class 2, and Class 3. Below is a brief summery of these alloys and their uses. For more details and additional alloys please reference our bar stock section or give us a call at 937-253-3300 to speak with one of our welding experts.

RWMA Class 1 (C15000 & C16200)

Also know as ZIRCONIUM-COPPER. This alloy is suited for high tempature applications such as welding aluminum & magnesium alloys. The Zirconium minimizes eletrode sticking when resistance welding coated materials. C15000 can be harder to find in larger sizes.

Material substitutes: C15000 Copper Zirconium and C18150 Copper Chromium Zirconium both are good replacements for C16200 Copper Cadmium. C15000 is a good subsitute because of its excellent thermal & electrical conductivity while still offering a moderate amount of strength. The C15000 hardness properties have been developed through cold working ( similar to C16200) but the C18150 hardness properties through heat treating, which can be an advantage for larger parts.

RWMA Class 2 (C18200 & C18150)

Also know as CHROMIUM-COPPER or ZIRCONIUM-CHROMIUM-COPPER. This alloy is suited to welding cold- and hot-rolled steels, stainless steel, and low conductivity brasses and bronzes.

Class 2: is 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. It is heat treatable.

NOTE : ZIRCONIUM-CHROMIUM-COPPER should be used when 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.

Over time this alloy has been know as: CMW 3, CMW 328, Mallory 3, Tuffaloy 77, and Tuffaloy Z, CuCr, CuCrZr, C18200, and C18150.

RWMA Class 3 (C18000 & C17510)

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

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

Also Known as: CMW 100, CMW 353, Mallory 100, Tuffaloy 55, Tuffaloy 55A, CuNiSiCr, Weldaloy 60, and CuNiBe.

RWMA Class 20

COPPER-ALUMINUM OXIDE (Glidcop) has exceptional resistance to deformation when resistance welding and it is recommended as a welding alloy 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. It is expensive and comes in minimum order amounts.

Also Known as: Elkaloy 20 and CuAL₂O₃

Don't see the alloy you're looking for? Give us a call or Please check out our copper alloys section.

ELKONITE

What is Elkonite?

Elkonite is a copper-tungsten alloy. Elkonite comes in up to 12 different alloys and many shapes and sizes. Copper and tungsten are not mutually soluble. Each material (tungsten and copper ) is comprised of a distinct metal which is then dispersed in to the matrix of the other through infiltration. Copper tungsten bars (Elkonite) is made when the tungsten powder W is pressed into the desired shape, sintered, and then infiltrated with molten copper.

When should I use Elkonite or copper tungsten as my electrode?

Choosing the right alloy for your application is important. Each alloy has different mechanical properties that can perform differently based on individual applications.

Elkonite encompasses a range of composite materials, predominantly alloys of tungsten and copper, with some variations incorporating elements such as molybdenum or tungsten carbide. These alloys are engineered to harness the best attributes of their components:

Material Properties: The tungsten in Elkonite offers a high melting point, wear resistance, and strength under elevated temperatures. The copper allows for superior electrical and thermal conductivity.
Elkonite comes in various grades, including 1W3, 3W3, and 10W3, each with a unique tungsten-copper ratio. Higher tungsten ratios enhance hardness and resistance against arc erosion, whereas more copper improves conductivity.

Role in Resistance Welding:

Electrodes and Dies: These alloys are used in resistance welding for applications like spot, projection, and seam welding:
- Flash and Butt Welding: Copper tungsten is used for die facings and inserts where both high electrical conductivity and thermal resilience are critical.
- Projection Welding: It's ideal for both light and heavy-duty projection welding dies, particularly under conditions of high pressure and heat.
- Cross-wire Welding: Its capability to handle high current with low deformation makes it suitable for joining large diameter wires or rods.
Durability and Resistance: The material's hardness and resistance to wear and electrical arcing extend the operational life of welding equipment, cutting down on maintenance and replacement costs.
Heat and Current Management: The synergy between tungsten and copper in Elkonite ensures effective heat dissipation and current flow, which is vital for maintaining weld quality and electrode durability.
Advanced Applications:
- Electroforming and Electroforging: Elkonite's wear resistance and thermal expansion properties are beneficial for die facing.
- EDM Applications: Its resistance to erosion from electrical discharges makes it suitable for EDM electrodes.

Specific Formulations:

Elkonite 10W3: Offers a balanced mix of conductivity and hardness, suitable for a broad spectrum of welding electrodes.
Elkonite 30W3 & TC10: These grades are particularly recommended for high-pressure projection welding due to their exceptional wear resistance.
Heat Treatable Variants: Such as 3W53 and 10W53, which gain additional hardness after brazing, making them apt for electroforging.

Elkonite's unique combination of properties positions it as an excellent material for resistance welding. Providing both differing conductivity and resistance to wear and heat. Its adaptability allows it to meet diverse welding challenges across industries, typically from manufacturing heavy industrial use.

Standard RWMA Shank tapers and force ranges

RWMA Male Shank Taper	Force Range	Taper size
4RW	The standard RWMA 4RW taper is designed for weld forces ranging from 200 - 800 LBS of force.	.463"
5RW	The standard RWMA 5RW taper is designed for weld forces ranging from 800 -1500 LBS of force.	.613"
6RW	The standard RWMA 6RW taper is designed for weld forces ranging from 1,500 to 2,000 pounds of force	.731"
7RW	The standard RWMA 7RW taper is designed for weld forces ranging from 2,000 to 2,400 pounds of force.	.844"

This page is still in progress, call 937-253-3300 for additional details or check back later.