Arc Welding Troubleshooting – Welding Defects, Problems & Easy Solutions [2024]

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How many times have you experienced a welding defect while working? The answer is probably too great to count. We’ve all been there and know exactly how it feels like.

Problems can arise because of the properties of the material being welded or the welders themselves.

Arc Weld Troubleshooting feature image

These defects and errors have made most of us dump the entire project and throw it in a scrap pile. Luckily, things don’t have to be this way. There are a bunch of solutions and answers to these problems that welders were able to resolve during their long careers.

Here are some arc weld troubleshooting and gas metal arc welding tips that could save your welding project the next time around.

About Weld Defects

Unfortunately, the majority of welding defects are our own fault. Weld issues are subject to improper technique, wrong parameter settings, or incorrect equipment settings. So when a defect during welding occurs, a welder has to count on his whits to deal with the situation.

Surface irregularities and weld discontinuation are the most common types of weld imperfections. Surface irregularities are conditions on the surface of the weld that contain abrupt changes in appearance or thickness. Weld discontinuities are interruptions of the structure of the weld. These may include an absence of homogeneity of the physical, mechanical, and metallurgical characteristics of the weld.

It is often necessary to perform weld quality testing to determine the level of the present weld defect.

Surface Weld Irregularities

Types of surface weld irregularities usually include something like a convex weld bead, a concave, overlaps, an undercut, or an uneven weld.

Concave and Convex Weld Beads

Proper welding should come with a flat and smooth weld bead. However, when concave or convex welds appear, you might as well throw everything away.

A concave weld happens when a welder is moving in a vertical-down pattern when working against gravity.

However, it can appear while working in a horizontal position because of high voltage, fast travel speed, or slow wire feed speed.

image of weld bead inspection

Convex weld beads usually occur while: working in a flat or horizontal position. They mostly appear as high or rope-like welds. They can also be seen in fillet welds when the parameters are too cold for the metal.

The best way of going about these problems is to: combine the use of correct welding amperage with correct electrode speed manipulation and do it at a proper travel angle.

Uneven Legs on Fillet Weld

Uneven legs are when the upper leg of the finished weld is shorter compared to the lower leg. This often happens due to an: Improper work angle of the rod.

Luckily, it is really simple to prevent this from happening as You must keep things steady and weld at an appropriate electrode angle which is 45 degrees.

Weld Undercut and How to Solve it

An undercut may appear when a groove in the base metal is left unfilled. There are a number of reasons why this may happen.

Usually, it is because of using high amperage, but it can also occur when:

  • Moving the rod too fast,
  • When the arc is too long and the voltage too high,
  • Inappropriate work angle and electrode travel, and even because of
  • Keeping the wire feed tracking too near to the groove face.

In order to avoid an undercut from happening a welder simply has to:

  • Set the appropriate welding amps,
  • Coincide the length of the arc, work angle, and electrode travel, or
  • Adjust the wire feed tracking location.

Excessive Weld Reinforcement

A problem may occur when applying too much joint reinforcement when there is a specific height that has to be achieved.

This usually happens due to:

  • Slow electrode manipulation,
  • High welding amperage, or
  • Too much root opening.

The way to prevent it is by:

  • Manipulating the rod at an appropriate speed,
  • Using the necessary amperage,
  • Adjusting the root opening, and
  • Controlling the electrode displacement.

Weld Overlap, Quick and Easy Solutions

An overlap is the bulge of metal beyond the root or a protrusion that occurs beyond the weld toe.

An overlap may happen when:

  • A user applies insufficient amperage,
  • Short arc length, or too low arc voltage,
  • Moves the electrode too slow, or
  • Works at an inappropriate electrode travel and work angle.

Luckily, overlapping can be avoided by:

  • Adapting to the appropriate welding amperage,
  • Using adequate electrode travel speed and work angle, or
  • Setting the arc length and voltage.

Weld Discontinuities Defect that Occur

Types of discontinuations that welders come across are porosity, incomplete fusion, incomplete, penetration, excessive burn-through, weld cracks, and slag inclusions.

Weld Porosity Defects That Usually Occur

Weld porosity happens when nitrogen, hydrogen, and oxygen are absorbed in the molten metal weld pool and then released on solidification and getting itself trapped in the weld metal.

There are a couple of scenarios where porosity may happen:

  • Rust, paint, moisture, and oil on the joint fusion may create high sulfur content on the base metal.
  • Moisture found in the coating, fluxes, or shielding gas.
  • Strong wind when working outside.
  • Insufficient shielding gas coverage or flux height.
  • Too much welding amperage or voltage.

The best way to avoid porosity altogether is to:

  • Clean the joint fusion faces and keep the coating, fluxes, and welding gas dry.
  • Use the correct amount of shielding gas flow and burden height.
  • Applying a windscreen when welding outdoors and
  • Adjust the proper amperage, voltage, and arc length will also help.

Incomplete or Poor Fusion

Lack of fusion usually means when the bond weld is not physically strong enough to hold to the walls of the joint and form a solid bead. Incomplete fusion can easily be seen as it is visible, and has to be removed to achieve a sound weld.

Problems with poor fusion happen when:

  • The input of amperage is too low,
  • Fast or slow electrodes manipulation,
  • Not enough or too much arc length or voltage, and
  • Too narrow of a welding groove.

The most common way to avoid lack of fusion is to:

  • Apply correct welding parameters and
  • Set an appropriate groove angle.

Incomplete Weld Penetration

Penetration is not visible to the naked eye and is the depth the weld enters into the base metal. If you want to create a strong weld, complete or full penetration has to be established to the bottom of the joint weld for a strong bond to be achieved.

Insufficient penetration occurs when:

  • The welding groove is too narrow,
  • The length of the welding arc and
  • Voltage is too high, the amperage is too low,
  • The travel speed of the electrodes is either too fast or too slow.

The best way to avoid problems with penetration is to:

  • Choose appropriate groove penetration,
  • Set the length and electrode travel speed settings, and
  • Apply correct welding amperage.

Excessive Burn-Through

Burn-through is the very opposite of incomplete penetration. A burn-through happens when you penetrate all the way through the base metal.

Burn-through occurs when there is

  • Too much root opening or
  • When a high welding amperage is applied.

Therefore, one has to:

  • Apply proper techniques and
  • Use the recommended root openings and welding amperages.

Weld Cracks – Types and Weld Issues

Cracks are a serious problem when it comes to welding and could lead to complete failure of the weld. There are different types of cracks that could occur in various locations throughout the weld. Because of this, cracking is viewed as an important subject and should be treated seriously.

Cold Crack (Root Crack, Toe Crack, Underbead Crack, Transverse Crack)

Cold types of cracks are created due to the solidification of weld metal at a temperature lower than 200C, the approximate one for steel. Cracks can happen in different places of the bead, root, toe, transverse to the bead, or under the weld bead.

A problem with cold cracks can happen when:

  • Diffusible hydrogen is found in the weld,
  • When restrain stresses occur in the weld, and
  • When the structure of the weld is brittle.

The best way to avoid cold cracks is to:

  • Redry the coating and fluxes and
  • Preheat the base metals.

Cold Crack (Lamellar Tear)

A lamellar tear is a crack that occurs under the weld of the base metal, parallel to the wrought surface.

Lamelar cracks are common when there is:

  • Inadequate ductility of the base metal,
  • Due to non-metallic inclusion in the base metal,
  • The high sulfur content in the weld metal,
  • Tensile stresses, and
  • Hydrogen in the weld.

Solutions to avoid lamellar tear are:

  • Using a base metal that has high ductility in the thickness direction,
  • Using electrodes with low hydrogen,
  • Making lower sulfur inclusions,
  • Decreasing the stress by changing welding procedures and joint details.

Hot Crack (Carter crack, Longitudinal Crack, Pear-Shape Crack, Sulfur Crack)

Hot cracking, the same as solidification cracking, is the result of the formation of shrinkage cracks while the metal solidifies. Hot cracking can also refer to liquation cracking.

Hot cracks appear because of:

  • High amperage input,
  • The high sulfur content of the base metal, and
  • Narrow welding grooves.

However, it can be avoided by:

  • Using the appropriate welding amperages,
  • Inspecting the sulfur content on the welding groove, and
  • Setting the recommended groove angles.

Slag Inclusions

Slag inclusions are the result of when a non-metallic particle is trapped in the weld metals or just between the base and the weld metal.

This can happen due to:

  • Low amperage settings,
  • The length of the arc,
  • Too much weaving width,
  • A and narrow groove.

Solutions for avoiding slag inclusions are:

  • Using appropriate groove angles and amp parameters,
  • Proper preparation by removing slag, and by
  • Keeping the weld axis in the horizontal position.

Other Common Welding Problems That Can Occur

There are additional welding problems that could occur depending on the process or welding technique at hand. If a welding system would have consistent output, it needs to have enough input. So let’s go through some other problems and welding troubleshooting that might cause a bit of frustration even for experienced welders.

ProblemPossible CauseSolution
Excessive Electrode ConsumptionInadequate/excessive gas flow

Improper size/or geometry of electrode for current required

Excessive heating in the holder

Contaminated electrode

Electrode oxidation during cooling

Using shield gas containing excessive oxygen or moisture
Test for correct gas flow (consult charts for gas flow guide)
Use larger electrode(consult the guide for proper geometry)

Check for proper collet contact

Replace electrode (erratic results will continue as long as contamination exists)

Depending on welding application, keep gas flowing for 5 to 15 seconds after stopping the arc

Change to proper gas purity
Contaminated ElectrodeThe base metal is dirty or greasy
Contaminant elements that outgas may exist within the base material itself

Check for electrode contamination
For surface, cleanliness use appropriate chemical cleaners alcohol, wire brush, or abrasive

If possible, improve the base material. Modify welding parameters to accommodate the outgassing effect

Remove a contaminated portion of the electrode, regrind electrode
Tungsten Contamination of Work PieceTungsten touching molten pool
Tungsten shedding

Electrode melting and alloying with base metal
Keep tungsten out of the molten pool
Use a quality Tungsten electrode grinder to sharpen electrodes

Use less current or larger diameter electrode
Porosity in the WeldEntrapped gas Impurities(hydrogen nitrogen, air, water vapor)
Defective gas hose or loose hose connections

Oil film on base meta
Purge air from all lines prior to striking arc, remove condensed moisture from lines; use welding grade (99.9%) inert gas
Check that the correct shield gas mixture is in use

Check hose and connections for leaks

Clean with chemical cleaner not prone to break up in arc.

Be sure base metal is dry before welding
Electrode MaterialBe sure electrode material is not changed. Try an electrode from another box or a stored reference boxDifferent electrode materials offer varying arc start and current-carrying abilities
Electrode Material QualityUse electrode from older or newer stock to see if the problem persistsA batch of electrodes may have varying quality (unusual)
Electrode Dimensions/GeometryBe sure electrode dimensions are appropriate for the applicationElectrode tip geometry varies according to the welding application. Consult guides for information
Cable LayoutIn so far as possible, try to layout cables from power supply to welding torch as straight as possible Occasionally, cables are coiled like a garden hose. The coil becomes a giant inductor causing resistance that reduces starting energy. Inductance effects can also be caused by having welding power cables very close to grounded steel plates
Extension CablesEnsure that any extension cables are of adequate capacityLow quality/capacity cables will result in voltage drops and hinder starting
Gas QualityGas quality/purity must meet standards. Check to see if suppliers have changed. Try a bottle of gas of a higher purity grade than normally used and see if the problem persists.The low gas quality or oxides in the gas can oxidize part and contaminate electrodes during welding. Even the best suppliers occasionally have problems.
Material Quality/SpecificationsBe sure materials you are welding do not have contaminants within their metallurgical structure. Check to see if there has been a change in material suppliersContaminants in the material can outgas during welding causing inconsistent weld quality. Arc wander or weld penetration variations may be a result of changes in certain trace minute elements in the material
Incorrect VoltageCheck the power supply for correct input voltage. It may be necessary to check voltages throughout the day to be sure that fluctuations are within the scope of the power supplyVoltage may be drawn from other equipment or facilities at peak times of the day. This will reduce the voltage available for the power supply to initiate an arc

Excessive Weld Spatter Problems

Spatter is not problematic when it comes to weld strength but greatly impacts the appearance, and it is also one of the most common weld problems that occur.

Spatter appears when the polarity, the size, and the type of the electrode do not match with the recommended settings. It also happens due to long arc, inadequate welding parameters, shielding gas composition, electrode angle, and dirty surface.

Excess spatter can be prevented by applying proper welding parameters, using a CO2-Ar shielding gas mix, and clean the surface before starting.

weld spatter

Wet Electrodes Problem

If you still happen to experience an erratic arc even after properly setting the polarity and the current, the problem lies in wet electrodes.

This happens when electrodes contain moisture or when inadequately storing your rods. Wet electrodes can be avoided by using fresh ones or storing the open container in an area with enough heat.

DC Stick Welding Wandering Arc

During DC Stick welding, a stray magnetic field can often cause the arc to wander. This happens more often when the current is high or when working on a complex joint.

A wandering arc usually happens with DC welding at high currents and when the welding arc is longer. Wandering can be reduced by using AC welding, reducing the current, using smaller electrodes to make a short arc, and making more connections in different places.

Accidental Arc Strikes

Arc stikes are usually the fault of welders when they accidentally make a connection with the workpiece to a live electrode. This can cause great damage to the piece of metal one is planning to weld.

This can be prevented by concentrating while working and by disconnecting the electrode before unsticking it.

Brittle Welds Defects

Improper welding techniques can also lead to brittle welds that are not able to hold up. This usually happens when using wrong-sized electrodes or when they are not properly shielded due to poor shielding gas flow. It can also occur with excess usage of welding current as well.

Brittle welds can be avoided by not using excessive welding current and by using shielding gas electrodes.

image of poor looking weld

Incorrect Wire Delivery

Incorrect wire delivery during MIG welding can easily be detected by ear when you hear an unusual sound coming out of your gun cable. This usually happens when a welder doesn’t set its equipment properly.

However, it may also occur due to improper maintenance of the tip that is too big for usage. Faulty wire delivery or wire feeding can be solved by checking the tip size and confirming whether the guide tubes and drive rolls are close enough to one another.

Weld Bead Corrosion

Using a filler metal that has a different composition than the base metal may produce potential electrochemical differences, causing corrosion to eventually occur. Besides not using the same filler as the weld metal, rust can also occur when using bare electrodes and when amounts of carbon appear when welding stainless steel.

Corrosion can be prevented by using shielded arc electrodes, matching the filler material, and cleaning the slag from the weld zone after finishing.

Weld Distortion Defects

While the welded metal is cooling down it also shrinks and pulls the metal around it, eventually creating distortion. Weld distortions happen due to uneven heating created by the workpiece and when the weld metal starts to shrink.

But you can prevent weld distortion by making sure that the joint is tight, using the most appropriate welding process for the job (MIG, TIG, MMA, etc.), not using excess power, and minimizing the heat input.

To Sum Things Up

No matter if you are using shielded metal arc welding (SMAW) or gas metal arc welding (GMAW), welding problems can occur and they will keep occurring. Whether it is because of the weld puddle, insufficient gas flow, the welder’s carelessness, or using the wrong technique, it still has a singular result – ruining everything that you have been working on.

But if you keep your head clear and follow all the instructions, especially the troubleshooting solutions mentioned above, you will not have to worry about your project becoming a potential dumpster fire.

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Adam Mason

Welder by trade for a decade and more. Now also a web designer and a blog owner. Doing product reviews and writing blogs about welding trade and perks and minuses of being a welder.

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