Given a double-J-groove, if the groove radius is 3/8", the root opening is 0 to 1/8", and the groove angle is 30°, what is the root face for a joint designation of B-U9-GF?

In the context of joint designations as per the AWS D1.1 Structural Welding Code, the designation of B-U9-GF indicates specific characteristics of the joint configuration being used. The "B" signifies a butt joint, while "U9" refers to the specific joint geometry and preparation used in conjunction with the double-J-groove.

For a double-J-groove configuration with a groove angle of 30° and a specified groove radius of 3/8", the root face should be calculated in accordance with the code rules. The root face refers to the flat area at the bottom of the groove, situated at the joint's root where the weld is deposited.

In this case, under the AWS D1.1 guidelines, the standard root face dimension for a double-J-groove joint with these parameters must account for both the radius and the configuration described. Given the information provided, the correct dimension for the root face aligns with the groove radius of 3/8".

Designating this as the root face takes into consideration that in both practical applications and code stipulations, the root face can effectively match the groove radius in configurations that do not require a larger dimension due to a lack of specified additional allowances or modifications.