What is an Undercut in Welding?

An undercut is a groove melted into the base plate adjacent to the weld toe or weld root and left unfilled by weld metal. It weakens the joint, particularly when located in a highly stressed area, and can act as a crack initiation site. Undercut can be minimized or eliminated by proper welding techniques, electrode selection, and joint design.

The undercut is typically characterized by its depth, width, and length. The width is measured at the base of the undercut, perpendicular to the welding direction. The depth is measured from the original surface of the plate to the bottom of the undercut. The length is measured along the weld bead, in the welding direction.

What cause undercut in welding?

Undercut can be caused by several factors, including:

incorrect welding techniques,
improper electrode selection,
and joint design.

To minimize or eliminate undercut, proper welding techniques, electrode selection, and joint design must be used.

The undercut is a common welding defect that can cause problems with the strength and integrity of a welded joint. It is important to be aware of undercut and its causes so that it can be minimized or eliminated during welding.

How do you prevent undercut in welding?

Prevention of undercut can be achieved by:

proper welding techniques,
electrode selection,
and joint design.

When these factors are considered, the risk of undercut is greatly reduced.

How do you fix undercut in welding?

Fixing the undercut can be done by:

removing the weld completely and starting over,
filling the undercut with weld metal,
or by grinding it down.

Where is an undercut found on a weld?

The undercut is typically found at the weld toe or weld root. It can also be found along the length of the weld bead.

How does undercut affect the strength of a weld?

An undercut can weaken a welded joint, particularly when located in a highly stressed area. It can also act as a crack initiation site. Undercut should be minimized or eliminated to ensure the strength of a welded joint.