Do you find yourself constantly facing common challenges in welding joints that leave you frustrated and discouraged? Don’t let these challenges hold you back any longer. With the right solutions and techniques, you can overcome any obstacle that comes your way.
Whether you’re a beginner or an experienced welder, there’s always room for improvement and growth. That’s where LPS comes in. We understand the struggles that come with welding joints and have developed the ultimate solution to all your welding problems.
Let’s look into the challenges and effective strategies that will save you time and effort, allowing you to focus on creating flawless welds with ease.
1. Cracking in welds
Weld cracking is a phenomenon that occurs when a weld joint fails to maintain its structural foundation, resulting in the formation of cracks. These cracks can significantly weaken the weld and compromise its strength and reliability.
However, by understanding different types of cracking and their causes, welders can take preventive measures to minimize the risk. The types include:
Cold Cracking
Cold cracking occurs when the hydrogen atoms in the weld combine with the carbon atoms in the metal and produce methane gas. These gasses can create heat in the weld and cause it to explode. Some types of cold cracking include:
- Toe Cracks – also known as hydrogen cracking, occur where hydrogen is emitted.
- Transverse Cracks – occur in the stronger areas of the steel.
- Root cracks – occur when the temperature of the metal drops below 400° F.
Solution:
The risk of cracking can be reduced by using good welding techniques such as preheating the base metal and controlling the heat output during welding.
In addition, low-temperature welding and storing and transporting welding equipment can also help reduce the risk of explosion.
Thermal Cracking
Thermal cracking is a welding problem that occurs during the solidification process. This is a type of crack caused by the stress of cold weather.
These stressors can be caused by many things, including restrictive expansion and contraction, too much heat, or an incompatibility between the parent’s products and the filler. Some types of thermal cracks are:
- Longitudinal cracks – cover the entire surface and occur mostly in concave welds.
- Lamellar Tears – occur only in rolled steel plates and are often associated with shrinkage deformations.
Solution:
To stop thermal cracking, a few things can be done. These include making sure the joints are correctly designed and have enough space, adjusting the welding settings to control the heat, and using filler materials that work well with the metal being used.
2. Porosity In Welds
Porosity is a defect that appears as small holes or voids in the welded metal. These holes reduce the strength of the weld and facilitate cracking and corrosion. Some of the causes of porosity include:
Incorrect use of shielding gas or flux
In gas metal arc welding (GMAW) or flux-cored arc welding (FCAW), it is crucial to have the right shielding gas or flux to protect the weld pool from contamination. If the gas flow rate is too low or the flux is not activated properly, it can lead to insufficient shielding and porosity formation.
Solution:
Welders can reduce porosity formation by ensuring proper gas flow and using good equipment.
Presence of Contamination
One of the main causes of weld porosity relates to contamination in the base metal or filler material. These contaminants, such as oil, grease, rust, or moisture, can evaporate during the welding process and create air pockets.
Solution:
Proper cleaning, such as degreasing, grinding, or using solvents, can help eliminate these bacteria and reduce the risk of pores.
Poor welding process
Weld porosity can happen when welding is done incorrectly. This can be due to using the wrong techniques or settings. Not enough heat, welding too fast, or not handling the electrode properly can all lead to porosity.
Solution:
Welders must be trained to follow proper welding procedures, including proper control of arc length, welding current and voltage, and maintaining walking speed.
3. Lack Of Fusion
Fusion (welding failure) occurs when there is not sufficient bonding between the weld metal and the base metal or between the layers of the weld metal. This defect causes the joints to become weak or damaged. Here are the causes and their corresponding solutions:
Insufficient heat input
Insufficient fusion can happen when there isn’t enough heat during welding. This can be because the welding machine is set to low power or the process is done too quickly.
Solution:
To fix this the heat input should be increased by adjusting the power settings or slowing down the welding speed.
Improper electrode angle
Another cause of insufficient fusion is using an incorrect electrode angle. If the electrode is not positioned correctly, it may not adequately melt the base material or create a strong bond between the layers.
Solution:
The solution is to ensure that the electrode is held at the appropriate angle, typically between 5 and 15 degrees, to allow proper fusion.
Inadequate cleaning of base material
Insufficient fusion may also arise when the base material is inadequately cleaned prior to welding. Contaminants like dirt, rust, or oil have the potential to delay the effective bonding of the weld metal with the base material.
Solution:
To prevent this, the welding parameters should be adjusted to ensure adequate penetration, such as increasing the current or using a different welding technique.
Incorrect welding technique
Using an incorrect welding technique can also contribute to a lack of fusion. For example, improper weaving or oscillation patterns can result in incomplete fusion between the weld metal and the base material.
Solution:
It is important to follow the recommended welding technique for the specific joint configuration and welding process being used.
Insufficient preheating
Preheating is necessary to ensure that the base material reaches the proper temperature for effective bonding with the weld metal. If preheating is not done adequately, the weld joint may not achieve the desired fusion.
Solution:
Always ensure that the base material is preheated to the recommended temperature range before welding.
Read: A Comprehensive Guide to OCTG in the Oil and Gas Industry
4. Excessive Spatter
Weld spatter occurs when hot liquid material is accidentally thrown or scattered while welding, resulting in the creation of unattractive blobs of molten material. Some of the most common problems and their solutions are discussed below.
Wrong gas composition
One of the common causes of excessive spatter during welding is improper shielding gas flow.
When the flow rate of the shielding gas is too high or too low, it can lead to an unstable arc and increased spatter.
Solution:
To minimize spatter in such cases, it is important to ensure that the shielding gas flow rate is set correctly according to the specific welding process and materials being used.
Contamination in base metal
Contaminants, such as rust, oil, or dirt, can create a barrier between the electrode and the base metal, causing the arc to become unstable and resulting in increased spatter.
Solution:
To minimize spatter in this case, it is crucial to thoroughly clean the metal surface before welding, using appropriate cleaning methods such as wire brushing or solvent cleaning.
Low quality of wire
Poor material of wire used in welding can also lead to excessive spatter.
Solution:
Use appropriate and high-quality material for your welding process. Ensure that the placement is done correctly to have the best results.
Conclusion
Armed with the solutions to common challenges in welding joints, you are now ready to conquer the trials that lie ahead. Stay tuned for more captivating insights from the passionate minds at LPS, your trusted companion in the world of welding and pipeline.
