When welding with SMAW, what groove angle is typically required for a TC-U4a joint?

A TC-U4a joint configuration is specifically used in groove welds where the joint is subject to tension. According to the AWS D1.1 code, for a TC-U4a joint, a groove angle of 30° is prescribed. This angle ensures that proper penetration and fusion occur during the welding process, which are essential to achieve the desired strength and integrity of the weld.

The 30° groove angle facilitates an appropriate balance between the accessibility for the welder and the ability to achieve good penetration, reducing the likelihood of defects. Using a groove angle that is too narrow may not allow sufficient filler material to be deposited or lead to inadequate penetration, while an excessively wide angle can complicate the welding process and lead to potentially weaker welds.