Porosity a common welding problem generally caused by absorption of the gases such as nitrogen, oxygen, and hydrogen in the molten weld pool, these are then released after solidification. Gases trapped in the weld metal.
Reason :
- Porosity is generally caused by the presence of moisture, grease, rust, or even paint on the plate edges.
- Another common reason for porosity can be insufficient gas shielding or when welding is executed onto minor openings and with air in between.
Solution :
- Porosity can be avoided in few different methods, by re-baking, or by using fresh welding consumables and keeping dry and clean edges of the plate.
- A welder must make sure that the welding torch to the plate angle is of the correct size and also check for any leaks.
- Keeping the gas nozzle of the welding device clean will surely help avoid this issue.
Cracks are the most common and expensive issue in welding. A crack can become larger over time and fixing the same is not as simple as filling any gap with the material. In order to correct this issue, a crack needs to be ground out and a new weld needs are required to be performed in order to correct the crack. Hence, preventing cracks is easier than fixing them.
Solution :
- Grinding, cleaning, filing, and deburring the edges of plates so they fit together nicely.
- Preheat both sides of the joint, making sure the temperature is correct.
- Also, check that we have the right amount of heat before welding by using our Tempilstiks temperature indicating crayon.
When droplets of molten material are produced near welding arc spatters are formed. This issue is common in gas metal arc welding (GMAW).
Reason :
Too high currents, incorrect polarity, or insufficient gas shielding.
Solution :
- Reduce the welding current and arc length.
- Increase the torch-to-plate angle.
- You should also double-check that the polarity, shielding gas type, and flow rates are all correct.
- Always keep the gas nozzle clean.
An undercut occurs when the arc voltage is too high or the arc is too long.
Reason :
- Incorrect electrode usage or an incorrect angle.
- Using an electrode that is too large for the thickness of the plate.
- Using a travel speed that is too quick can also lead to an undercut.
Solution:
- Always observe the speed of the weld.
- Monitor how much weave is used.
- Avoid holding the electrode near the vertical plate when making a horizontal fillet weld.
- Avoid using an electrode bigger than needed.
Deformation occurs during the contraction of welded metals when cooling and hardening.
Reason :
- When the welding sequence is not suitable for the intended weld.
- Too many thin beads.
- Insufficient clamping before welding.
Solution :
-
- Weld from both sides of the joint.
- Weld from the center out, in opposite directions.
- Use a large electrode and clamp firmly.
- Change the sequence of the welds and location of the joint if deformation begins to occur.
- Make fewer passes during welding.
- For thin plates, you may apply Tempil Anti Heat on both of the plates. This will contain heat dissipation and reduce deformation.