What is Under-Bead Crack/Cracking in Welding?

Under-bead crack is a weld defect that starts in the heat-affected zone and is caused by excessive molecular hydrogen trapped in that region. It is sometimes referred to as cold cracking since it occurs after the weld metal has cooled.

How do prevent cracks in welding?

This defect can be prevented by using low-hydrogen welding consumables and ensuring that the weld joint is clean and free of contaminants. In addition, preheating the base metal before welding can also help to reduce the risk of under-bead cracking.

What are the 3 basic types of cracks in the weld metal?

There are three basic types of cracks in the weld metal:

Under-bead crack.
Lamellar tear.
Incomplete fusion/penetration.

What caused cracking on weldment beads? 5 causes of weld crack

The main causes of cracking on weldment beads are:

Incomplete penetration.
Improper welding techniques.
Excessive cooling rates.
High residual stresses.
Contamination of the weld joint.

What is the difference between an under-bead crack and a lamellar tear?

The main difference between an under-bead crack and a lamellar tear is that an under-bead crack starts in the heat-affected zone, whereas a lamellar tear starts at the interface between the weld metal and the base metal.

How to fix cracks in welding?

The best way to fix cracks in welding is to use low-hydrogen welding consumables and ensure that the weld joint is clean and free of contaminants. In addition, preheating the base metal before welding can also help to reduce the risk of under-bead cracking.

Crater crack welding

A crater crack is a weld defect occurring at the end of a welding bead. It is caused by the sudden cooling of the weld pool, which leads to the formation of cracks in the weld metal.