CEMP-E
TI 809-26
1 March 2000
(5) Square groove welds have limited application for structural steel. They are better suited for thin
materials. When square groove welds are used, the root opening must be closely controlled and the
Welding Procedure Specification (WPS) closely developed and followed.
(6) For thick materials, generally starting at thicknesses of 50 mm (2 in.), J- and U-groove welds
may be more economical than bevel- and V-groove welds. The wider root initially requires more weld
metal, but the narrower groove angle reduces the total weld volume below that of bevel- and V-groove
welds. There are also higher initial joint preparation costs to prepare a J- or U-groove joint, so even more
weld metal must be saved to recover these costs. When angular distortion or shrinkage strains must be
minimized, J- and U-groove joints should be considered. The reduced groove angle minimizes the
differential in weld width from top to bottom of the joint.
(7) Root opening widths should be generous but not excessive. Wider root openings allow for
complete penetration to the bottom of the joint preparation. However, very wide roots contribute to root
pass cracking and root HAZ cracking from weld shrinkage. Narrow root openings contribute to lack of
penetration, lack of fusion, and trapped slag at the root.
(8) Groove angles should be the minimum angle that will provide adequate access for penetration
to the root, and adequate access to the groove faces for complete fusion. Excessively wide groove
angles contribute to added angular distortion, increased risk of shrinkage cracking, increased risk of
lamellar tearing in T-joints, and higher costs because of the additional material and labor used.
e. Prequalified Joint Details. The prequalified groove weld details in AWS D1.1 Figure 3.3 for Partial
Joint Penetration (PJP) groove welds, and Figure 3.4 for Complete Penetration Joint (CJP) groove
welds, provide root opening, groove angle, root face, thickness limits, tolerances, and other information
for the effective detailing of groove welds. Root openings and groove angles are considered adequate for
the welding processes and positions noted, without causing excessive angular distortion. For PJP groove
welds, the required depth of preparation is provided to achieve the desired effective throat. When the
joint details as shown are used, qualification testing of the joint detail is not required to verify the
suitability of the detail, provided other prequalification provisions of the Code are also met. See AWS
D1.1 Section 3 for these limits. The use of prequalified groove weld details does not guarantee that
welding problems will not occur. The details may not always be the best detail, and other more efficient,
cost-effective or easier-to-weld details may be used. However, when other groove details are used,
qualification testing is required.
f. Qualified Joint Details. Groove weld details may be used other than those shown as prequalified in
AWS D1.1 Figures 3.3 and 3.4. Alternate details may be selected with reduced or wider root openings,
reduced or wider groove angles, or other revised details. Generally, narrower root openings and groove
angles increase the risk of incomplete penetration at the root and lack of fusion along the groove faces.
These problems may be minimized through the use of suitable WPSs. Qualification testing, as
prescribed in AWS D1.1 Section 4, is required in such cases to verify the ability of the WPS to provide
the penetration and quality necessary.
g. Distortion. Angular distortion can be minimized through the use of double-sided welding, the use of
minimum groove angles, J- or U-groove welds, presetting of parts, and WPS selection. Double-sided
welds balance weld shrinkage about the center of the part's cross-section. When the part can be
frequently rotated for welding on opposite sides, a balanced groove detail can be used. When one side
will be welded in its entirety before proceeding to weld the opposite side, the first side groove depth
should be approximately 35-40% of the total groove depth of both welds. The completed first side weld
restrains the second side weld from shrinking as much as the unrestrained first-side weld. Minimum
5-3
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