What are the welding defects

       

What are the welding defects

What is a welding defect? Defects that do not meet the requirements of the standard during the welding process. What is a stomata? In the welding process, the gas in the molten pool metal cannot escape before the metal cools, and the holes formed in the weld metal (inside or on the surface).

What is welding defect

 

Defects produced during the welding process that do not meet the requirements of the standard.

 

 

 

What is a stomata?

 

In the welding process, the gas in the molten pool metal cannot escape before the metal cools, and the holes formed in the weld metal (inside or on the surface).

 

 

 

What is crack?

 

Under the joint action of welding stress and other brittle factors, the gaps formed in the weld metal and heat-affected zone (internal or surface) are called cracks.

 

1. Thermal cracks—cracks that occur immediately after welding at high temperatures.

 

2. Cold cracks-cracks that occur when the metal is cooled to room temperature after welding; or cracks that occur a few hours or days after welding are called delayed cracks.

 

 

 

What is undercut?

 

Due to incorrect selection of welding parameters or incorrect operation method, grooves or depressions produced along the base metal part of the weld toe (fusion line)-called undercuts, will cause local stress concentration.

 

 

 

What is incomplete penetration?

 

The phenomenon that the root of the joint is not completely penetrated during welding.

 

 

 

What is unfused?

 

During fusion welding, between the weld bead and the base metal or between the weld bead and the weld bead, the part that has not been completely melted.

 

 

 

What is welding spatter?

 

During the welding process, the molten metal particles and slag are scattered around.

 

 

 

What is solder bump?

 

During the welding process, the molten metal flows to the metal nodules formed on the unmelted base metal outside the weld.

 

 

 

What is slag inclusion?

 

The phenomenon of welding slag remaining in the weld.

 

 

 

What is a crater? How to prevent it?

 

When the arc is received during welding, a depression crater that is lower than the height of the weld is formed at the end of the weld bead-called arc crater. Generally, there are defects such as low-melting eutectic, inclusions, and crater cracks in the arc crater.

Use the arc closing current (less than 60% of the welding current) to stay in the arc crater for a certain period of time, and fill the arc crater with metal powder to prevent arc crater defects.

 

 

 

What is non-destructive testing? What does it have?

 

A method of detecting defects without damaging the performance and integrity of the inspected material or finished product. There are:

X-ray flaw detection (RT)

Ultrasonic flaw detection (UT)

Magnetic particle inspection (MT)

Penetration testing (PT), etc.