Burn Through Welding Causes and Tips to Avoid Them

Marcus Colson Last updated on September 4, 2023
Reading Time: 4 Minute

As a welding enthusiast, I want to share my struggles with different types of welding defects.

One of the most challenging ones for me is burn through welding.

This defect refers to small holes that occur because too much heat is applied to a particular point.

So, it causes burning through the metal.

In this article, I would like to share my experiences about burn through weld along with factors that cause this defect.

Also, I’ll provide some tips to prevent this welding defect.

Burn Through Welding Definition

What is burn through in welding?

Burn-through, which some people may call melt-through, is a kind of defect in welding.

This defect looks like a hole occurred in the weld joint.

Usually, it appears next to the weld seam.

I often experience this defect when I work with thinner material or metal with lower thermal conductivity.

Then, our welding burns dangerous?

The answer is an absolute yes.

This defect can decrease the strength of the weld joint. Undercut, porosity, and other welding defects will weaken the weld joint.

The holes may lead to cracks. It can be said that the welding process failed. My clients often reject the result of welding when they find any burn-through.

This rejection often happens in pipe welding projects. It is because the hole in the joint can cause leakage in the pipe.

Therefore, burn-through not only impacts the appearance of welded metal. But it also affects the strength and performance of weld joints. 

Read Also : What is Welding Spatter: Causes and Tips to Avoid It

What Causes Burn through in Welding?

There are a lot of factors that can lead to burn-through.

Based on my experience, burn through welding defect causes are related to the welding technique, preparation, and other aspects such as current and electrode.

Both preparation and execution stages play a crucial role in determining the result of welding.

Here are some factors that can contribute to creating holes or melt-through in the weld joint.

1. Too High Current

Every workpiece requires a different level of current.

So, I always check the chart or manuals to find the right current for every project.

When I use higher amperage or current, the burn-through often appears.

How can it happen?

Welding at a high current setting can result in too much heat. It causes the metal to melt too quickly and leads to a burn-through.

2. Moving Electrode Slowly

Another aspect that can lead to the welding defect is the electrode’s speed of moving.

The slower I move the electrode, the more heat the metal accepts. It will cause a similar effect as high amperage.

Greater heat results in over-melting and holes. I can determine the right travel speed by practicing and concentrating more.

3. Dirty Base Metal

Before welding the metal, I always clean the base metal to prevent defects.

Proper cleaning is necessary, especially when I weld galvanized aluminum and steel. These metals are layered with a thin film.

If I do not remove this coating, it will be difficult to weld it.

It is because this layer reacts when I heat it. Then, it can create impurities and burn-through.

Also, before welding, check whether the metal surface is contaminant-free. Rust and dirt can cause the metal to heat up unevenly, leading to burn-through.

4. Incorrect Welding Technique

I want to share my experience using the MIG (Metal Inert Gas) welding technique.

The welding gun must be held at a specific angle to the welded metal.

Failure to maintain the correct angle can cause too much heat to be directed at a particular point, leading to burn-through welding defects.

Similarly, when I use TIG (Tungsten Inert Gas) welding technique, the electrode must be kept at a specific distance from the metal being welded to maintain the right heat input.

Failure to do so can cause burn-through.

5. Incorrect Setting on Welding Machine

A welding machine has several buttons that have different functions.

For example, it has knobs and buttons to change the current, polarity, voltage, and wire feed speed.

Before welding, I always check the setting to ensure they are all correct.

The welding process can become unpredictable when these settings are not properly adjusted. Then, it leads to various defects, including burn-through.

How to Prevent Burn through in Welding

Experiencing welding defects such as burn-through is annoying. It is because the welding process failed, and the quality is low.

So, here I try to share several tips for avoiding burn through welding based on my experience.

Use a Lower Current Setting

When welding, it is important to use the correct, current settings based on the thickness of the metal.

For example, when I weld thin metal, I always use lower current settings to avoid burning through the metal.

Proper Joint Preparation

Before welding, make sure the metal surfaces are clean and contaminant-free.

This is particularly important when welding thick metals, as they require more heat input to melt.

Clean metal surfaces will help the metal heat up evenly. So, it reduces the possibility of burn-through.

Weld Faster

To prevent excessive heat on the metal, try to move the electrode faster.

Also, avoid weaving patterns. It is better to weld thin metals using a straight line as it can eliminate burn-through.

Use TIG or MIG Technique

It is necessary to adjust the welding gun based on the technique. I recommend using mild techniques such as metal inert gas or tungsten inert gas.

When using the MIG technique, hold the electrode at the correct angle.

Besides, keep the electrode at the right distance from the base metal when using the TIG technique.

These actions are useful to maintain the right heat input.

Read Also : Excess Reinforcement in Welding: Causes and How to Avoid

How to Fix Burn-through?

Even though I have practiced a lot, sometimes I still find burn-through on my welding workpiece.

If it happens to you, you do not need to worry since I will share how to repair the burn-through.

This defect is in the form of a small hole. So, the best way to fix it is by filling it.

Then, what if this defect has uneven edges?

Make sure to grind these edges before tacking a weld.

In addition, to repair multiple burn-through, I usually make a new pass over the previous weld joint. These tips really work, and I can have better welding results.

Always pay close attention to the current settings, joint preparation, welding technique, and electrode or filler wire, and take breaks when necessary.

With practice and patience, I’m sure that you can become a skilled welder who produces perfect welds every time.

In conclusion, burn through welding can be a frustrating and costly defect.

However, with the right techniques and tips, it is possible to prevent burn-through and achieve high-quality welds.

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Marcus Colson
Marcus Colson

Welding is more than a hobby for me - it's a passion. The art of fusing metal together to create something new and functional never gets old. From intricate sculptures to sturdy structures, I love the endless possibilities that welding offers.

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