Problem: Poor Fusion
Poor fusion is associated with incomplete penetration and is likely a structural fault. Often, poor fusion cannot be detected without a radiographic examination of the weld. This weakness may be present in a weld that outwardly appears to be strong and perfect.
Causes of poor fusion are:
- The welding speed is too fast.
- Improper current setting.
- Failure to prepare joint properly.
- Wrong size welding electrode.
To prevent poor fusion:
- Remember that heavier plates require more
current for a given electrode than small plates
do. Be sure to use sufficiently high welding
current to insure correct deposition of weld
metal with a good penetration of the base metal.
- In connection with welding technique, be sure
the weave is wide enough to thoroughly melt
the sides of the joint.
- In preparing the joint, be sure the face of
the groove is clean and free of foreign material.
- Use an electrode sufficiently small to reach
the bottom of the groove in making the weld.
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