In a groove weld, what is the gap at the joint root between workpieces called?

The gap at the joint root between workpieces in a groove weld is called the root opening. This term specifically refers to the space created between the edges of the material being welded at the root of the groove. The purpose of the root opening is to allow adequate penetration of the weld metal into the joint, which is critical for ensuring the strength and integrity of the weld.

Understanding the root opening is essential for welders because it affects factors such as the weld's strength and the ease of achieving a good weld bead. Properly defining and adhering to the specifications for the root opening helps ensure that the weld will perform as needed under load.

The other terms do have their distinct meanings in welding practice. For example, the actual throat refers to the shortest distance from the root of the weld to the face of the weld. Bevel angle relates to the angle of the edges of the workpieces, and groove angle pertains to the angle formed between the two parts of the groove itself. However, these terms do not specifically refer to the gap at the joint root.