Square-Edged Groove Welds

On a square-edged groove weld, the base metal at the joint is not beveled or prepared in any other way. A gap may be provided between the two members to be joined, resulting in a root opening that helps facilitate joint penetration. In other cases, the joint may be butted tight, and joint penetration is fully dependent upon the penetration supplied by the welding process. Figure 3 illustrates how a “nothin’ weld” can occur with square-edged groove welds. While the designer expected a complete joint penetration weld like that in the top illustration, a combination of variables can lead to the partial joint penetration weld shown in the lower example. In the extreme, the strength of the connection may be due only to the surface reinforcement. Yet, the visually discernible weld on the surface cannot be used to gauge the likely degree of penetration that has been achieved.

The D1.1 places fairly severe restrictions on the use of these joint types. For example, prequalified joint details B-P1a, BP1b and B-P1c are limited to a maximum thickness of 1/4 in. All other thicknesses require some type of joint preparation, whether the intended weld is a complete joint penetration groove weld or partial joint penetration groove weld. For non-D1.1 Code work, or when using non-prequalified joint details, it is possible to successfully make CJP groove welds on materials as heavy as 1 in (25 mm) thick if welded from both sides, even when a square-edged groove weld is employed. However, rigorous control must be placed on the welding procedures used in production, and electrode placement with respect to the joint is critical. Spot checks of production parts are highly recommended to ensure that the production system is sufficiently robust to ensure consistency. Alternately, groove weld details that employ prepared
surfaces for vee and beveled groove details, for example, can be employed to avoid this form of a “nothin’ weld.”

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