What is the base metal thickness of T for joint TC-U4a with a back-up strip?

For the joint configuration TC-U4a with a back-up strip, the base metal thickness is specified according to the requirements set forth in AWS D1.1. This particular joint type is a groove weld that utilizes a back-up strip to support the molten weld pool, aiding in the production of a sound weld and minimizing defects.

In the context of the AWS D1.1 code, TC-U4a typically involves joining two plates where the thickness of the base metal is a critical factor in determining the appropriate welding procedures and parameters. The specification for TC-U4a states that for a back-up strip, the minimum base metal thickness that should be utilized is 1/2 inch.

This thickness is essential because it ensures that the weld can achieve sufficient penetration and bead profile while effectively managing heat input and minimizing warping or distortion during the welding process. Additionally, this thickness requirement helps maintain the structural integrity and performance characteristics of the welded joint under specified loads. Thus, 1/2 inch is the correct answer for the base metal thickness of T in this context.