Common defects in ERW pipe welding and their preventive measures

During the welding process of ERW pipes, various defects may occur. It is very important to understand the causes of these defects and take preventive measures. The following are several common defects that ERW pipes may encounter during welding and their preventive measures:

1. Slag inclusion
Defect manifestation: impurities such as slag are present in the weld.
Cause: In multi-layer welding, the interlayer cleaning is not clean; the welding current is too small, and the slag is not easy to float out; the rod feeding method is improper.

Preventive measures: Thoroughly clean the welding slag after each layer is welded; appropriately increase the welding current; use the correct rod feeding method.

2. Incomplete penetration
Defect manifestation: Incomplete fusion between the parent material and the weld metal.
Cause: The welding current is too small; the groove angle is too small; the welding rod angle is incorrect.
Preventive measures: Increase the welding current; process the appropriate groove; adjust the welding rod angle.

3. Incomplete fusion
Defect manifestation: Incomplete fusion between the weld metal and the parent material or between the weld metals.
Causes: welding current is too small; welding speed is too fast; preheating temperature is not enough.
Preventive measures: increase welding current appropriately; reduce welding speed; increase preheating temperature.

4. Cracks
Defect manifestation: cracks appearing in the weld.
Causes: welding materials do not match the parent material; welding structure design is unreasonable, stress concentration exists; welding sequence is improper.
Preventive measures: select suitable welding materials; optimize welding structure design; formulate reasonable welding sequence.

5. Undercut
Defect manifestation: the parent material at the edge of the weld is melted by the arc to form a depression.
Causes: welding current is too large; arc is too long; welding rod angle is incorrect.
Preventive measures: reduce welding current; shorten arc length; adjust welding rod angle.

For example, when welding steel structures, if the groove angle is too small and the welding current is also small, it is easy to have defects of incomplete penetration, resulting in insufficient weld strength. In pipeline welding, if the welding speed is too fast and the current is too small, there may be problems of incomplete fusion, affecting the sealing of the weld.

In short, understanding the causes of ERW pipe welding defects and taking effective preventive measures are crucial to ensuring welding quality.

Read more: ERW pipe vs. HFW pipe or Carbon Steel ERW Pipe Specification