Welding is a complex craft that requires a lot of experience and learning. Many defects may occur if you don’t have sound knowledge about the welding process. Burn-through welding is the most common defect many novice welders may face. Do you also encounter a burn-through while fabricating a thin steel sheet? Welding at high temperatures can be challenging to avoid blowing holes in your project. The right tools may help, but only when you know the usage.
We know for a welding enthusiast, it would be so heartbreaking to see a welding burn through after completing your job. In this blog, we will go over some of the most common causes of burning through welding and how to identify and avoid them. This will allow you to be more proficient in your field.
What is burn-through welding?
You may find a burn-through on the parts of root beads where you do excessive arc penetration that causes the weld puddle to be blown into the inside of the joined parts.
How Does Welding Burn Through Happen?
You run the risk of burning through your workpiece if:
- You’re unfamiliar with the metal you’re working with.
- High amperage during the welding of the root pass on butt welds.
- Immoderate root grinding, which may cause the welding to burn through.
- Don’t have the correct machine settings.
- Don’t know the proper techniques for the process you’re using.
These are some common reasons that you may face as a beginner. Despite that, Burn-through welding may happen for various reasons. Some of which are mentioned below:
1. Excessive Amperage
Amperage (current) plays a crucial part while welding a thin metal plate. Even many experienced welders sometimes accidentally burn through the base metal with higher amps. You must be extra careful while working with any metal less than 1\4 inches thick.
Always check your amperage setting if you see any melt through your welding join. Amperage essentially determines how much current flows through the electrode and the workpiece, which in turn affects the arc temperature. More current results in a higher arc temperature.
Every metal needs a different level of amps. If you want to do your job smoothly, ensure you are doing your job according to the recommended amps. You can find the correct amps for each job on the catalogs and charts or ask any professional.
2. Wrong selection of the electrode
This is another essential part of the excellent weld appearance. An electrode’s packaging will tell you all the necessary information regarding the level of the amp, their metal, current use, flux coating, performance, chemical and mechanical properties, and the position of welding. Make sure that you are using the right electrode for the job you are doing.
3. Excessive Grinding of the base metal
Before you start welding, make sure that they’re clean. This helps prevent porosity, cracking, or blowing holes in the base metal. Especially MIG and TIG welders don’t work well on a dirty surface.
Moreover, it is essential to remember that you should not over-grind the surface because the metal becomes thin and thus vulnerable to melt through welding.
4. Improper penetration
Most people in the metalworking industry think that excessive penetration is often harmful. Maintaining a proper penetration level is very important, as too much can lead to burning through the metal instead of into it. However, some specific techniques can be used to increase penetration if needed.
5. Inadequate know-how about the base metal.
As it is said, knowledge is the key to success. So you should have accurate information about the metal you are working with. Suppose you are working on galvanized steel or aluminum. In that case, you should thoroughly clean the workpiece before welding as they have an oxidized layer on the surface that becomes more reactive at high temperatures.
Aluminum oxide is present as a thin film on every aluminum piece. When welding, the oxide layer reacts with other hot metals in the weld pool to produce slag. This reaction makes it difficult to control the weld pool, which tries to move away from the weld zone. As a result, heat from the torch goes into the base metal rather than being absorbed by the weld, leading to burn-through.
6. Wrong welding process
Today welding involves a lot of processes and various equipment. Sometimes, the wrong choice of welding process may cause a melt-through. Every welding process has its usage. For example, arc welding is used for high amperage and deep penetration.
If you use the arc welding process for thin metal sheets and soft base metal, you risk burning through the metal. Likewise, MIG and TIG welding is primarily used for delicate work and thin metal sheets. Selecting an exemplary process is the first step toward the overall appearance of welded joints.
7. Improper machine setting
Burn through also happen if you set your machine poorly. Always check the setting of your welder. There are tons of buttons and knobs available for different settings.
You can quickly burn through the base metal if you do not go after the proposed settings. Do your research for the task you are going to take up and act under the guidelines to avoid burn-through and other welding defects.
You may need to change the current level and polarity differently for different jobs; ensure that your machine setting is good enough to prevent burning holes in the metal.
8. Poor welding techniques
There is no proper replacement for on-the-job experience when it comes to welding or other skilled professions in life. By practicing often, you’ll gradually figure out which welding techniques work best for your job. As you learn more, you’ll be able to do things correctly. It will help if you remember the above techniques while doing your job.
How can you prevent the welding burn through?
Fortunately, you can easily avoid burning holes through welding once you know the causes. Moreover, you can avoid them by following these preventive measures.
1. Act in accordance with the guidelines
If you want to avoid unnecessary delay and burning defects, always use a welding chart and never go against the specifications that your welding machine’s manufacturer recommends. If you do not have a welding chart, you can find one easily online or from a local welding supply store.
Likewise, every electrode has specifications given by AWS (American welding association). Check the specs before using the electrode. If you are a beginner, it is good to use E 6013 for most of your jobs. It works best on thin metal sheets as well as all positions and current settings.
On the other hand, if your job requires deep penetration and you want to weld thick metal, then go for E 6010. However, remember that E6010 only works best on DC; if you go against the recommended setting, you may burn through the metal.
2. Set welder properly
The main culprit of burn-through is excessive heat which melts the base metal. This happens when your welder’s amps are set too high. Try to use lower current input to prevent burning holes through excessive heat.
It’s essential to follow the recommended input level given in the machine’s user manual to prevent many defects, including burning holes. However, you can also find the perfect setting by frequently adjusting the machine’s current flow.
3. Clean workpiece\ Avoid over grinding
Ensure to clean the welding surfaces thoroughly in order to avoid any welding problems later on. You can use a grinder or metal wool for this purpose. While grinding, take care not to leave the metal too thin at the bottom. If it’s too thin, it won’t be able to combat the excessive heat.
4. Watch out for the root opening
One way to prevent burn-through is monitoring the root opening. The root opening is the separation that happens at the joint of the root between the two pieces you are working on. If it is too large, it could cause the metal to burn holes.
5. Use recommended welding patterns
Try to use this recommended welding pattern to prevent burning holes in welding.
- Try not to weave your torch side to side during welding. Whipping may be good for you but not for the welding bead so try to avoid it. That will eliminate both burns through and warping.
- Always use the straight pass to prevent the welding burn through. Also, try to be quick without forgoing your bead.
- If you notice burn-through while welding, an excellent way to combat it is by reversing your travel direction while keeping the electrode angles the same. By doing so, you’ll be able to deposit more heat onto the bead rather than the base metal.
- To avoid any issues with your welds, ensure you’re consistent with the heat. If the heat is distributed evenly, it can not burn through the metal.
1. How do you fix burn-through in welding?
Burn-through is a type of welding defect that occurs when the heat from the weld penetrates too deeply and melts through the base metal. Burn-through is most commonly caused when using too much heat.
The best way to fix burn-through is to weld over the existing joint to fill the whole, using less heat and taking care to weld slowly and evenly. If it is bumpy, you may need to grind down the hole’s edges before welding over it.
To do so, choose suitable backing material. Copper, brass, and aluminum all work well for this purpose. Another tip is to start on the outside edges of the hole and work your way toward the center when you’re making weld repairs. By following these tips, you’ll be able to make weld repairs more efficiently and with less hassle.
2. Why is my MIG welder burning holes?
There might be the following reasons your MIG welder is burning holes: Immoderate heat; try to set the current flow on a lower level.
If you are staying in one spot for too long, try to move straight quickly without weaving.
The best way to weld is to be in a position where you can move quickly along the weld line, be aware of your settings, and have everything under control in your mind.
Blowing holes through the welding is the prime problem that may come your way when you are new to the welding industry. Many different factors can contribute to burn-through. It could be due to something as simple as high current and travel speed. Other times, it may result from negligence in joint preparation, cleaning the base metal, etc. However, with some practice and know-how of the causes, you can easily avoid them.