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5 Common Causes of MIG Weld Porosity: Bad MIG Welding

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Metal fabrication frequently involves MIG welding. However, even skilled welders occasionally run into problems like porosity in their welds. A common welding flaw called porosity can weaken a weld’s structure and ultimately cause it to fail.

In this blog post, we’ll look at five typical reasons why MIG weld porosity occurs and how to avoid it. Welders can produce robust, high-quality welds that meet their unique needs by comprehending the causes of porosity and using the right welding techniques.

5 Common Reasons for Porosity in MIG Welding

  1. Contamination on base metal from paint, dirt, or oil
  2. An improper chemical balance between filler and base metal
  3. Inadequate shielding gas or flux
  4. The machine not working properly due to poor maintenance
  5. Improper welding technique

Reason 1: Contamination on Base Metal

During MIG welding, contaminants that are present on the base metal’s surface can cause porosity. The contaminants start to vaporize when the welder heats the metal, and the vaporized material creates gas pockets inside the weld. The weld becomes less strong and is more likely to fail as a result of these gas pockets.

Common contaminants that can result in porosity during MIG welding include paint, dirt, and oil. Paint and oil can obstruct the weld pool’s ability to properly bond to the base metal by standing between it and the metal. By introducing foreign material into the weld pool, dirt can also result in porosity.

It’s crucial to properly prepare the base metal before MIG welding in order to avoid porosity. To get rid of any contaminants, the base metal’s surface needs to be thoroughly cleaned. To accomplish this, clean the metal’s surface of paint, grime, and oil using a wire brush or grinder.

Reason 2: Improper Balance between Filler and Base Metal

A filler material is used to fill the joint between two metal pieces during welding. The filler material is typically fed through the MIG gun into the weld pool in the form of a wire. The base metal is the metal being welded, and compatibility between the filler material and the base metal is crucial.

Inadequate proportions between the filler and base metal can result in porosity. This can occur in a variety of ways. One possibility is that the filler material contains an excessive amount of gas, causing bubbles in the weld.

Another possibility is that the filler material is unable to properly penetrate the base metal, resulting in gas pockets in the weld.

Reason 3: Inadequate Shielding Gas

In MIG welding, shielding gas is used to shield the weld pool from the atmosphere. By shielding the weld pool from oxygen and other airborne gases that could cause porosity in the weld, the shielding gas aids in preventing weld contamination.

Porosity can result from inadequate shielding gas in a number of different ways.

Inadequate shielding gas can lead to porosity by allowing too much air to contact the weld pool, for example. Air can enter the weld pool and create pockets of gas that lead to porosity if the shielding gas flow rate is too low, or if there are leaks in the gas lines or the gas nozzle.

Turbulence in the weld pool is another way that insufficient shielding gas can result in porosity. Gas bubbles may become trapped in the weld if the shielding gas is not directed properly onto the weld pool. This might cause porosity and make the weld weaker.

It’s crucial to make sure that the shielding gas flow rate is suitable for the welding circumstances in order to avoid porosity brought on by insufficient shielding gas.

The flow rate must be sufficient to form a stable shield around the weld pool while not being too high to cause turbulence. Regular inspections of the gas lines and nozzle are also necessary to look for any leaks or obstructions that might let air into the weld pool.

Reason 4: Poor Machine Performance

Poor maintenance can cause the MIG welding machine to malfunction, which can result in weld porosity.

One way that poor maintenance can result in porosity is by obstructing the wire feed’s flow. The wire feed mechanism could get stuck or jam if it is improperly lubricated, which could disrupt the weld. These breaks could cause gas pockets to form in the weld, which would weaken it.

Poor maintenance can also result in porosity by having an impact on the shielding gas delivery system. The shielding gas flow can be disrupted and air can enter the weld pool if the gas nozzle is blocked or damaged. This might cause porosity and make the weld weaker.

The MIG welding machine’s electrical components can be harmed by poor maintenance. Corrosion or damage to the electrical connections may result in electrical current fluctuations, which may result in uneven welding. Porosity, as well as other flaws like cracks and weak spots, can be a result of inconsistent welding.

It’s crucial to adhere to a regular maintenance schedule for the MIG welding machine to avoid porosity brought on by inadequate maintenance.

The wire feed mechanism must be lubricated, the gas nozzle must be inspected and cleaned, and the electrical connections must be checked for damage or corrosion.

To ensure the machine runs as efficiently as possible, any parts that are found to be harmed or worn out should be replaced right away.

Reason 5: Improper Welding Technique

Inadequate shielding gas is one of the ways that bad welding techniques can result in porosity. Gas bubbles may become trapped in the weld if the shielding gas is not applied to the weld pool in the proper direction by the welder.

This might cause porosity and make the weld weaker. The shielding gas flow rate must be appropriate for the welding conditions, and the gas lines and nozzle must be free of leaks or obstructions that might let air into the weld pool.

By using the wrong electrode, improper welding methods can also result in porosity. For instance, using the incorrect electrode type or weaving the electrode too widely can result in porosity and a lack of shielding gas.

Because very little shielding gas is produced, for instance, the E7018 electrode should not be weaved wider than two and a half times the electrode diameter.

The result is that some of the welds are exposed. Porosity can be created by airborne nitrogen from the weld pool that dissolves and then gets trapped during the escape.

Different Types of Porosity

There are four main categories of porosity:

porosity types in welding

1- Uniformly scattered porosity is most frequently caused by poor welding techniques or faulty materials.

2- Clustered porosity is most often caused by improper starting and stopping techniques.

3- Linear porosity is most frequently brought on by contamination at the joint, root, or inter-bead boundaries.

4- Piping porosity, or wormhole, is typically brought on by contamination at the root. This porosity is distinctive because it can only form when the gas in the weld pool is escaping at the same rate as the pool is solidifying.

porosity types in welding

Few Tips to Prevent Porosity in MIG Welding

There are a number of techniques welders can employ to prevent Porosity. Here are some tips for avoiding porosity during MIG welding:

1- Properly Prepare the Surface: Before beginning the welding procedure, it is essential to ensure that the surface to be welded is clean and free of any dirt, oil, or other contaminants. This can help prevent porosity by providing a clean surface for the welding wire to adhere to.

2- Use the Correct Gas Flow Rate: To prevent porosity, it is essential to use the correct gas flow rate. The gas flow rate should be set according to the size, type, and welding parameters of the weld. The correct flow of shielding gas will aid in preventing contamination in the weld pool, which can lead to porosity.

3- Choose the Appropriate Electrode Wire: To prevent porosity, use the proper welding wire and electrode. Different types of welding wires and electrodes have distinct properties, so it is essential to select the appropriate one for the task. For instance, using a wire that is too small or too large for the weld can result in porosity.

4- Maintain Proper Wire Feed Speed: Maintaining proper wire feed speed is essential to preventing porosity. The wire feed speed must be adjusted based on the size and type of the weld, as well as the welding parameters. The correct wire feed speed will aid in maintaining consistent weld quality and avoiding porosity.

5- Maintain the Correct Arc Length: Maintaining the correct arc length is also very essential to preventing porosity. Typically, the ideal arc length ranges between 1/4 and 1/2 inches. If the arc length is too long or too short, it can cause fluctuations in the electrical current, which can create inconsistencies in the weld.

6- Avoid Weaving the Electrode Too Wide: Weaving the electrode too broadly can result in a lack of shielding gas and lead to porosity. It is crucial to avoid weaving wider than 2.5 times the diameter of the electrode.

7- Check for Gas Leakes: Before beginning the welding procedure, it is essential to inspect the system for gas leaks. Even small leaks can result in porosity, so it is essential to seal the gas lines and nozzle properly.

8- Use the Correct Polarity: The welding machine’s polarity must be set correctly for MIG welding. Using the wrong polarity can result in porosity and other welding defects. Consult the manufacturer’s instructions to determine the correct polarity settings for your welding machine and application.

9- Avoid Welding in Windy Conditions: Welding in windy conditions can disrupt the shielding gas and result in porosity, so it should be avoided. It is not necessary to work in a well-ventilated space, but you should also avoid areas with strong winds or draughts.

Final Words

In conclusion, porosity is a typical welding flaw that can jeopardize the integrity of a weld. Welders can prevent this problem by recognizing the typical causes, such as incorrect shielding gas, poor maintenance, an unbalanced ratio of filler to a base metal, poor welding technique, and problems with wire feed speed.

Welders should always adhere to accepted welding procedures, utilize high-quality tools, and routinely check their welds for porosity. They can produce durable, high-quality welds by doing this.

Informational

How to Weld If You Have Long Hair? Pro Welder’s Tips

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Any welding operation that you perform puts you and anyone else in the area in danger of a number of different things. As a result, it is completely reasonable for you to be concerned about preventing your hair from becoming entangled in any welding equipment and posing a threat to your health. In this article, I will talk about how you can safely weld if you have long hair.

If you want to weld while having long hair, a French braid is the best option for keeping your hair together. This will help you in tying your hair and hold it together behind your neck. The French braid should keep the hair compact and close to your head’s shape, and it also allows you to wear a welding helmet. As a result, you will be able to wear full safety equipment.

When you are dealing with hot weld spatters, having long hair can present a particularly difficult challenge. Therefore, if you are interested in learning more about how you can safely weld with long hair, continue reading the rest of this article, where I will discuss the topic in greater detail and share some helpful hints.

How Your Long Hair Can be an Issue While Welding?

Welding procedures, as I indicated earlier, expose the operator as well as anybody else in the vicinity of the workplace to a wide variety of risks. A project involving welding presents a number of potential dangers and threats; it is important that you be aware of these issues in order to protect not only yourself but also others around you. Especially when dealing with spatters, it is easy for things to go wrong if you have long hair.

Before we look at all of the tips you may weld with long hair, we need to first understand the potential risks you run and everything that might go wrong. Long hair poses a unique set of challenges when it comes to welding. A few are mentioned below:

  • Spatters are your hair’s worst enemy.
  • UV rays can permanently damage your hair.
  • With long hair, grinders can cause serious accidents.

Let’s look at these problems one by one:

1. Take Spatters Seriously 

The spatter, sparks, and heat generated by the arc provides the greatest challenge throughout the welding process since they may travel up to 35 feet and enter any nearby place. You will want to provide enough protection for your long hair if you are going to be in an atmosphere like this.

Not just your hair, but everything else that might catch fire should be kept at least 35 feet away from the welding location. In addition, a fire extinguisher should never be far away. In the event that a fire breaks out.

2. UV Rays Can Damage Your Hair Permanently

Molten metals, welding arcs, and ultraviolet radiation will be present in the work environment while welding is being done. The interaction of all these factors puts you at an increased risk of serious burns. The actual welding arc may reach temperatures of up to 10,000 degrees Fahrenheit, making it one of the hottest processes possible.

And believe me when I say that you do not want that welding arc to get anywhere near your hair. Your hair will suffer a significant amount of damage as a result, and it is possible that it could even be burned.

3. Grinder Can Give You Nightmares

The usage of grinders is another factor that may create issues for your lengthy hair. Using grinders and welding go hand in hand when working with metals. Therefore, if you are a welder, you will most likely make extensive use of the grinder. And grinders are really your worst enemy when it comes to your long hair.

When you’re working, you can find yourself crouching over a grinder, which can cause serious accidents if you don’t protect your hair properly.

Tips from a Pro Welder to Protect Your Long Hair When Welding

Now you know what the most obvious dangers that you have when welding with long hair. The next step is to tell you how you can keep yourself safe from those dangers.

Here are a few of the tips that you can consider:

  • Braid your hair while welding
  • Put your hair in a tight knot behind your neck
  • Consider buying a welding cap
  • You can use a bandana too if you are a bandana lover

Let’s discuss these tips one by one:

Braid hair woman welding

1. Braiding is the Best Option You Have

Welding hoods, helmets, or shields will provide the optimum amount of protection from any sparks, heat, UV rays, flash burns, or infrared light that may be present. They will protect not only your face and neck but also your eyes and hair. As a result, I feel that acquiring one is the best approach to protecting oneself.

Welding hoods are often made of cotton or leather and are rather light in weight and can go easily along with helmets. Make sure that whichever helmet you decide to purchase, is not too heavy and that it is comfortable to wear. It must also include a spatter barrier, the ability to be modified, a sensor bar, and the availability of replacement components.

2. You Can Simply Put Your Hair in a Tigh Knot

The most conventional and easiest technique for a welder operator to keep their long hair out of their face is to pull it back into a tight bun. Wrap an elastic band over your buns and secure them in place to prevent them from falling on your face.

If there are any unruly hairs, just use bobby pins to push them up and you should be OK. Anything that prevents your hair from falling on your face will suffice.

3. Consider Buying a Welding Cap

A welding cap is a good option if you want something that is both lightweight and comfortable. It must adequately shield your head from any hot metal, sparks, or splatters that may be present.

Not only they are effective in protecting your hair, but they are also made completely of cotton, making them incredibly breathable and also preventing sweat from pouring down your eyebrows while working.

4. Bandana is Another Option That You Can Use

Braids are not easy to create for everyone, and they may even be difficult to perform on a regular basis. If you don’t know how to braid my easiest suggestion would be to put a bandana over your head and tuck all of your hair within.

When welding, sparks will fly everywhere, and this will keep you safe. Make use of bobby pins or a bun to tuck in all of the ends. Bandanas aren’t my first choice for headgear. But it works. It’s a good option to have in case you don’t know how to braid your hair.

Few Other Safety Measures That You Need to Take

In addition to your hair, there are a few other parts of your body that need your attention. Some of these essential measures for ensuring your safety are listed below:

  • Protect your eyes at all cost
  • Always keep a fire extinguisher in your shop
  • Wear protective clothing
  • Make habit of using respirators
  • Beware of leakages in your welding system
  • Keep your welding space clean

Let’s discuss them one by one:

1. Protect your eyes at all cost

Be sure to always wear safety glasses in your workplace to protect your eyes from flying debris, which is often composed of metal. If you routinely do welding tasks, you will be exposed to a significant amount of flying debris.

You should make it a routine to put them on as soon as you come in the door; this will ensure that you are protected at all times.

2. Always keep a fire extinguisher in your shop

You shouldn’t be shocked if anything catches fire at some time during a welding operation because of all of the intense heat and sparks that are produced throughout the process. Because fires are a very real risk, you should always have an extinguisher on hand in case one breaks out.

3. Wear protective clothing

If you’ve ever imagined yourself beginning your first welding project in a pair of shorts, an old t-shirt, and a pair of flip-flops, you should rethink that idea. Wearing the necessary protective clothing at all times when welding is required if you wish to prevent injuries to your body, notably burns, that may be caused by the process.

4. Make habit of using respirators

You should always wear a respirator if you are going to be dealing with metals or any other materials that have the potential to emit harmful vapors.

Welding or cutting certain materials may produce a welding plume, which is a combination of hazardous gases, fumes, and smoke. This is not the type of thing you want to breathe in if you want to keep your lungs healthy and prevent respiratory issues.

If you are interested in knowing more about respirators and their types, please check out my other article.

5. Beware of leakages in your welding system

There is a good chance that you have pressurized containers in your welding shop that hold liquids or gases. Take extra precautions to check that none of those containers or the items that you are attaching to them have any leaks in them.

See my other article to know more about leakages and how to detect them.

6. Maintain your equipment

If you want to establish the safest possible working environment for your welding projects, you need to give your equipment a lot of TLC and make sure it’s in good operating order at all times. If your welding equipment and tools are in disrepair, an accident is almost waiting to happen every time you use them. However, the vast majority of incidents of this kind are avoidable if proper care is taken with the equipment.

Wrapping it Up

When it comes to welding, safety is the most important thing to keep in mind at all times. Because because welding involves a significant amount of fire and spatters, it is essential that you take a significant amount of precaution to protect your hair. I really hope that you’ll be able to keep your hair under control while welding thanks to the advice that’s been provided in this article.

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Weld Types

Different Welding Methods: Applications of Each Method

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Welding is joining two pieces of metal together by melting and cooling them until they become one piece. Welding processes include:

  • Oxyacetylene welding
  • Shielded metal arc welding (Stick)
  • Gas tungsten arc welding (TIG)
  • Gas metal arc welding (MIG)
  • Flux-cored arc welding
  • Torch or oxyfuel brazing

Some methods employ both heat and pressure, while others employ only heat. Welding is commonly used to construct automobiles, airplanes, and buildings. Other metal-cutting methods, such as oxy-acetylene and plasma arc cutting, use heat or electricity to cut through metal.

1. Oxyacetylene welding

Oxyacetylene welding (OAW) is a method of joining two pieces of metal using heat generated by the combustion of oxygen and acetylene gas.

Torch brazing (TB) is similar, but the metal is not completely melted. Instead, a special alloy is melted and used to join the two metal pieces.

Oxyfuel gas cutting (OFC) is a method of cutting metal that uses the same tools and gases as OAW and TB.

To generate heat and bond the metal, all of these methods employ a torch and special gases. They are frequently used on small or thin metal pieces.

Applications:

  • Welding and brazing thin or small pieces of metal
  • Welding and brazing dissimilar metals
  • Cutting and piercing metal

Situations to Avoid:

  • Welding thick or heavy sections of metal
  • Welding high alloy or stainless steel
  • Welding in high wind or outdoor conditions (due to the open flame)
  • Welding in confined spaces (due to the production of harmful gases)

2. Shielded metal arc welding (Stick)

Shielded metal arc welding, or SMAW, is a way of welding metal together using an electrode that is coated with a special kind of flux.

The electrode melts and becomes a part of the welded metal. To do SMAW welding, you need a transformer, two welding cables, a work clamp, and an electrode holder.

There are many different types of electrodes you can use for SMAW welding, so you can choose the one that is best for your project. With SMAW welding, you can join different types and thicknesses of metal using the same machine.

Applications:

  • Welding thick or heavy sections of metal
  • Welding in outdoor conditions
  • Welding in dirty or contaminated environments
  • Welding on dirty or painted surfaces

Situations to Avoid:

  • Welding thin or small pieces of metal (more suited for TIG welding)
  • Welding high alloy or stainless steel (can affect the quality of the weld)
  • Welding in confined spaces (due to the production of harmful gases)
  • Welding in the presence of high winds (due to the electric arc)

3. Gas tungsten arc welding

GTAW, or gas tungsten arc welding, is a method of joining metal using a tungsten electrode. The tungsten electrode generates an electric arc, which melts the metal being welded as well as the end of the filler metal, which is manually applied.

Shielding gas is emitted from the welding gun to protect the molten weld metal from dirt and other contaminants. A foot or thumb switch can be added to the GTAW equipment to help the welder better control the welding.

GTAW welding produces very clean, high-quality welds, but it is slower and requires more skill than other welding methods. It is particularly useful for joining metal alloys that can only be joined with GTAW.

Applications:

  • Welding thin or small pieces of metal
  • Welding high alloy or stainless steel
  • Welding in outdoor conditions (with proper shielding gas)
  • Welding materials with high levels of contaminants or impurities
  • Welding in high-precision environments

Situations to Avoid:

  • Welding thick or heavy sections of metal (more suited for MIG welding)
  • Welding in high production environments (slower process)
  • Welding in confined spaces (due to the production of harmful gases)
  • Welding in the presence of high winds (due to the electric arc)

4. Gas metal arc welding (MIG)

Mig welding is a type of arc welding that uses a continuously supplied wire electrode and gas to weld metal together.

It is becoming more popular because it is easier to learn than other types of welding, like stick and tig welding, and it is faster because you don’t have to stop and change the electrode as often.

Mig welding also creates less slag and spatter, which makes it more enjoyable to use and easier to clean up.

However, MIG welding equipment is more expensive and the MIG gun, which is the portable part of the equipment, can be difficult to use in small spaces. Mig welding also requires a shielding gas to work, so it is not as good for outdoor use.

Applications:

  • Welding thick or heavy sections of metal
  • Welding high alloy or stainless steel
  • Welding in high-production environments
  • Welding in outdoor conditions (with proper shielding gas)

Situations to Avoid:

  • Welding thin or small pieces of metal (more suited for TIG welding)
  • Welding in confined spaces (due to the production of harmful gases)
  • Welding in the presence of high winds (due to the electric arc)
  • Welding materials with high levels of contaminants or impurities (can affect the quality of the weld)

5. Flux-cored arc welding

Flux-cored arc welding, or FCAW, is a method of joining metal using a special type of electrode wire known as a flux core wire.

The wire is fed from a spool continuously through the welding equipment and out of the gun. The welding current flows through the equipment, melting the wire and the base metal.

Some flux core wires generate their own shielding gas as they melt, while others require the use of additional shielding gas. As the wire melts, it produces a gaseous cloud that shields the weld surface and removes impurities from the molten metal.

After the weld is completed, a layer of slag must be removed from the weld’s top. Despite this additional step, FCAW is a popular welding technique because it produces high-quality welds quickly and is very versatile.

FCAW equipment is similar to that used in gas metal arc welding (GMAW), and both methods are semiautomatic, which means that the wire is fed automatically but the welder moves the gun manually. Welding supply stores and other retailers stock FCAW equipment and filler metals.

Applications:

  • Welding thick or heavy sections of metal
  • Welding in outdoor conditions (with proper shielding gas)
  • Welding in high-production environments
  • Welding in dirty or contaminated environments

Situations to Avoid:

  • Welding thin or small pieces of metal (more suited for TIG welding)
  • Welding high alloy or stainless steel (can affect the quality of the weld)
  • Welding in confined spaces (due to the production of harmful gases)
  • Welding in the presence of high winds (due to the electric arc)

Comparison Table:

Welding ProcessApplicationsSituations to Avoid
Oxyacetylene weldingWelding and brazing thin or small pieces of metal; welding and brazing dissimilar metals; cutting and piercing metalWelding thick or heavy sections of metal; welding high alloy or stainless steel; welding in high wind or outdoor conditions; welding in confined spaces
Shielded metal arc welding (Stick)Welding thick or heavy sections of metal; welding in outdoor conditions; welding in dirty or contaminated environments; welding on dirty or painted surfacesWelding thin or small pieces of metal; welding high alloy or stainless steel; welding in confined spaces; welding in the presence of high winds
Gas tungsten arc welding (TIG)Welding thin or small pieces of metal; welding high alloy or stainless steel; welding in outdoor conditions (with proper shielding gas); welding materials with high levels of contaminants or impurities; welding in high-precision environmentsWelding thick or heavy sections of metal; welding in high production environments; welding in confined spaces; welding in the presence of high winds
Gas metal arc welding (MIG)Welding thick or heavy sections of metal; welding in high production environments; welding in outdoor conditions; welding on dirty or painted surfacesWelding thin or small pieces of metal; welding high alloy or stainless steel; welding in confined spaces; welding in the presence of high winds
Flux-cored arc weldingWelding thick or heavy sections of metal; welding in high production environments; welding in outdoor conditions; welding on dirty or painted surfacesWelding thin or small pieces of metal; welding high alloy or stainless steel; welding in confined spaces; welding in the presence of high winds
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