Manual Metal Arc (MMA) welding, also known as stick welding, is one of the oldest and most versatile welding methods around. Whether you’re welding outdoors, working on rusty surfaces, or handling various materials, MMA welding has got you covered. However, as straightforward as it may seem, this technique isn’t without its challenges.
From porosity to slag inclusions, numerous issues can affect the quality of your welds. But don't worry—we're here to break down Megmeet-welding 10 most common MMA welding problems and offer practical solutions to fix them. Let’s dive in!
Flaw 1: Porosity in Welds:
Porosity is the presence of tiny holes or gas pockets within the weld metal, which can weaken the weld and make it susceptible to cracking.
1) What causes it：
Moisture in the electrode or on the workpiece.
Contaminants like oil, grease, rust, or paint.
Using an excessively long arc length.
2) Megmeet's Solutions:
Always store electrodes in a dry environment to prevent moisture absorption. If your electrodes are damp, consider baking them at a low temperature before use.
Clean the base metal thoroughly to remove any contaminants before welding.
Maintain a short, stable arc length to minimize exposure to atmospheric gases.
Flaw 2. Slag Inclusions
Slag inclusions occur when non-metallic solids (slag) get trapped in the weld metal. This defect can reduce the strength and integrity of the weld.
1) Why It Happens:
2) Megmeet's Solutions:
Use a chipping hammer and wire brush to clean the slag from each pass before starting the next one.
Adjust your electrode angle to around 20-30° relative to the workpiece.
Ensure you're using the correct current settings for your electrode type.
Flaw 3. Cracking in Welds:
Cracks are a serious defect that can compromise the strength and durability of a welded joint. They can form during cooling or after the weld is complete.
1) What causes it：
Rapid cooling or thermal stress.
High levels of hydrogen in the weld area.
Using the wrong type of electrode for the material.
2) Megmeet's Tips:
Preheat the workpiece if you’re welding thicker or high-carbon steel to reduce cooling rates.
Opt for low-hydrogen electrodes and ensure proper storage to avoid moisture absorption.
Use post-weld heat treatment if necessary to relieve residual stress.
Flaw 4. Lack of Fusion:
Lack of fusion means the weld metal fails to properly bond with the base metal, leading to weak joints that can break under stress.
1) What causes it：
2) Megmeet's Solutions:
Increasing the welding current to improve penetration.
Slowing down your travel speed to give the weld metal time to fuse.
Ensuring proper preparation of the joint by grinding or cleaning edges.
Flaw 5. Undercutting:
Undercutting is a groove that forms at the toe of the weld bead, reducing the thickness of the base metal and weakening the joint.
1) What causes it：
Excessively high welding current.
Moving the electrode too quickly.
Incorrect electrode angle.
2) Megmeet's Solutions:
Lower the amperage if you notice undercutting.
Slow down your travel speed to allow the weld metal to fill the joint properly.
Keep the electrode at an angle of around 15-20° from the vertical.
Flaw 6. Excessive Spatter:
Spatter refers to small droplets of molten metal that get ejected from the weld pool, creating a mess on your workpiece.
1) What causes it：
Using too high a current or arc voltage.
Holding the electrode too far from the workpiece.
Using poor-quality or damp electrodes.
2) Megmeet's Solutions:
Adjust the current and voltage settings according to the electrode specifications.
Maintain a short arc length to reduce spatter.
Use high-quality electrodes and store them properly.
Flaw 7. Arc Blow:
Arc blow occurs when the arc becomes unstable, often resulting in uneven weld beads or poor penetration. It’s particularly common in DC welding, especially near magnetic materials.
1) What causes it?：
Magnetic fields in the workpiece.
Improper ground clamp positioning.
Welding too close to previous welds.
2) How to Combat Arc Blow::
Reposition the ground clamp to a different location.
Use AC welding if possible, as it's less prone to arc blow.
Change the direction of your welding to counteract magnetic forces.
Flaw 8. Burn-Through (Excessive Penetration):
Burn-through happens when the weld metal penetrates too deeply, causing holes in the workpiece, especially on thinner materials.
1) What causes it?：
2) Prevention Tips:
Reduce the amperage to avoid excessive heat.
Speed up your travel rate to prevent overheating.
Choose a smaller diameter electrode for thinner materials.
Flaw 9. Difficulty Striking an Arc:
If you find it hard to strike or maintain an arc, it can disrupt your welding process and lead to poor weld quality.
1) What causes it?：
Damp or poor-quality electrodes.
Incorrect amperage settings.
Lack of experience or technique.
2) Megmeet's Solutions:
Use fresh, dry electrodes and store them in a moisture-free environment.
Adjust the amperage based on the electrode size.
Practice on scrap metal to get a feel for the correct arc-striking technique.
Flaw 10. Weld Bead Inconsistency:
Inconsistent weld beads can be aesthetically unappealing and may indicate issues with weld quality.
1) What causes it?：
2) Megmeet's Solutions:
Maintain a consistent arc length throughout the weld.
Practice steadying your hand and controlling your movements.
Check your machine settings and adjust them as needed.
Conclusion:
MMA welding is a skill that takes time and practice to master. But by understanding these 10 common MMA welding problems and their solutions, you’re already one step closer to becoming a pro. Whether it's porosity, cracking, or arc blow, addressing these issues head-on will save you time, materials, and frustration in the long run.
Remember, the key to great welding is preparation. Clean your materials, set up your machine correctly, and practice proper technique. Soon, you’ll be laying down beautiful, strong welds that you can be proud of. If you want to learn welding tips or welding solutions, you can collect Megmeet News Center Page or follow our LinkedIn page.
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4. MMA "Stick" Welding: What is Open Circuit Voltage (OCV)?
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