What Causes Undercut in Welding

Introduction

Welding is the process of joining two or more metal pieces by heating them to a high temperature and then cooling them. While welding, it is essential to achieve a strong bond between the pieces. One of the common issues faced during welding is undercut. Undercut is the depression formed at the edge of the welded joint, which reduces the strength of the joint. In this article, we will discuss what causes undercut in welding.

Causes of Undercut in Welding

Undercut can be caused by various factors, some of which are listed below:

1. Improper Welding Technique: One of the common causes of undercut is an improper welding technique. If the welding gun is not held at the correct angle or distance from the workpiece, it can cause the heat to be concentrated on the edges of the joint, resulting in undercut.
2. Excessive Welding Current: Excessive welding current can also lead to undercut. When the welding current is too high, it can cause the metal to melt excessively, leading to a depression at the edge of the weld joint.
3. Low Welding Speed: Low welding speed can also cause undercut. When the welding speed is too slow, the heat input becomes excessive, leading to a depression at the edge of the weld joint.
4. Incorrect Electrode Angle: The electrode angle is essential while welding. If the electrode angle is too steep, it can cause the heat to concentrate on the edges of the joint, leading to undercut.
5. Inadequate Preparation: Proper preparation of the workpiece is necessary to avoid undercut. If the edges of the workpiece are not properly cleaned, it can cause impurities to be trapped in the joint, leading to undercut.

Preventing Undercut in Welding

Undercut can be prevented by taking the following measures:

• Proper Welding Technique: It is essential to use the correct welding technique while welding. The welding gun should be held at the correct angle and distance from the workpiece to avoid the concentration of heat on the edges of the joint.
• Optimum Welding Current: The welding current should be adjusted to the optimum level to prevent excessive melting of the metal.
• Correct Welding Speed: The welding speed should be maintained at the correct level to prevent excessive heat input.
• Electrode Angle: The electrode angle should be adjusted to the correct level to avoid the concentration of heat on the edges of the joint.
• Proper Workpiece Preparation: The workpiece should be properly cleaned and prepared to avoid impurities being trapped in the joint.