A joint root condition in a groove weld where weld metal extends through the joint thickness is known as what?

The term that specifically describes a joint root condition in a groove weld where the weld metal extends completely through the joint thickness is "CJP," which stands for Complete Joint Penetration. This terminology indicates that the weld fully penetrates the joint, ensuring a solid bond throughout the entire thickness of the materials being joined.

CJP is essential in applications where the strength of the weld is critical, as it provides maximum load-bearing capacity and minimizes the chance of defects or failure at the joint. In contrast, other answers represent different concepts in welding. While "Full Penetration" may sound similar and is often used interchangeably in some contexts, "CJP" is the more precise term used in welding codes and standards to denote the complete penetration through the joint.

Understanding these terms is vital, especially in developing welding practices that adhere to specific engineering requirements and safety standards.