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How to Choose Contact Tips for MIG Welding

Date: 08-06-2022

How to Choose Contact Tips for MIG Welding

 

Metal inert gas (MIG) welding is a key process involved in a wide range of applications. The high-quality, sturdy welding technique can be done with minimal downtime and is easy to pick up – even for beginners. 
 
One of the most essential parts in a MIG welding setup is the contact tip. This is the point in which the welding current is transferred to the wire and creates the arc. 
 
MIG welding contact tips are available in a range of sizes, materials, and other specifications, such as the type of metal alloy. Choosing the correct tip for the correct applications can mean the difference between a hatchet job and a job weld done. 
 

Size Matters Most!

Before we get into the common types of contact tips, it’s important to outline the importance of choosing the right size tip. 
 
The size of the welding tip refers to the thickness of the wire which feeds through it. The wires are graded with a number that determines the thickness of the wire; the higher the number, the thicker the wire will be. As you increase in wire thickness, the welding torch generates more heat. 
 
Sizes range from .024” to .094”. Larger size wires generally get the job done faster, although it’s highly recommended to read your MIG torch’s specifications and match the correct size contact tip with it. 
 

Common Welding Tip Types

There are five different types of contact tip that are commonly used in welding applications, and each have their own pros, cons and suited applications:

 

1. Standard Copper Welding (E-Cu)

A standard copper welding contact tip has a fairly high current transfer rate and is most commonly used in hand-held welding applications.

Standard copper is relatively soft, which means it makes electrical current transfer easier, but it has a lower melting point. As the temperature rises in a copper welding contact tip, it becomes softer than the wire that is being fed through it. As the copper softens, the wire wears and misshapes the diameter of the tip. This prevents the wire from connecting with the tip correctly – decreasing conductivity and ultimately leads to burnback, arc-start issues, and poor welds.

Despite this, the E-Cu tip is usually the most affordable and is generally accepted when concise wire targeting is not critical.

 

2. Copper-Chrome-Zirconium Welding Contact Tip (CuCrZr)

A copper-chrome-zirconium welding contact tip is most commonly used in automated and robotic welding applications. It’s a popular choice for precision welding or for heavy-duty cycles. Although there is some loss in electrical conductivity compared to an E-Cu tip, it is still suited for most steel applications.

Copper chrome zirconium welding contact tips are a must-use in laser welding optics due to its ability to endure hot wire feeding processes.

 

3. Silver-Plated Welding Contact Tip

Over the years, advancements in contact tip technology have revealed that silver plated welding tips enhance overall welding performance. This is mostly due to silver being far more conductive than copper – this ultimately reduces micro-arcing, extends contact tip life, provides consistent weld quality and improves the arc starts. 

Based on the overall longevity, current transfer, and quality of material, silver-plated tips are an excellent choice for automatic and robotic welding applications. 

 

4. Heavy Duty Silver-Plated Contact Tip

By using a process known as dispersion-hardening, the Heavy Duty Silver-Plated welding contact tips can last even longer than regular Silver-Plated contact tips. 

Dispersion hardening, or strengthening, is a technique where hard or soft external particles are introduced into the aluminium alloy matrix. This technique gives the contact tip a hardness value of 180, which means it won't experience wear until the tip temperature reaches upwards of 800 degrees C! 

 

5. Stainless Steel Contact Tip

Stainless Steel contact tips have poor electrical conductivity compared to copper and silver-plated tips, however they make up for this with a greater resistance to wear and tear.

They are highly recommended when using copper wire in laser optic and cold wire feeding processes – and are also highly recommended when using copper wire. If you are using aluminium wire, it’s best to consider a copper-based contact tip profile as stainless steel is often too hard.

 

Contact Alphaweld Today

At Alphaweld we are always ready to share our expertise and find the best solution for all of your welding needs. To speak with our team of trusted experts, give us a call on (08) 9456 8000 or visit us online – and we’d be more than happy to help.