Fabrication and Installation - Offshore Structures: Design, Construction and Maintenance - page 297

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containers should be stored at 70 C, depending on type of electrode.

When electrodes are withdrawn for use, they should be kept in heated contain-
ers and used within 2 hours. Consumables that have been contaminated by
moisture, rust, oil, grease or dirt should be discarded. Surfaces to be welded
should be free of mill scale, slag, rust, grease, oil and paint. Edges should
have a smooth and uniform surface.
The fitter should be working before the start of welding. A check of the dimen-
sions should be performed. Misalignment between parallel members should not
exceed 10% of the thickness or 3 mm. If the thickness of abutting members differs
by more than 3 mm, the thicker member should be tapered by grinding or machin-
ing to a slope of 1:4 or flatter, as shown on Figure 5.1 . Certain completed welds that
are critical for fatigue endurance may be required to be ground to a smooth curve.
This also reduces the probability of brittle fracture.
Welds that are essentially perpendicular to the direction of applied fluctuat-
ing stresses in members important to the structural integrity are normally to be
of the full-penetration type and, where possible, they should be welded from
both sides. Intersecting members for which the welding details have not
been specified in the design should be joined by complete-penetration groove
welds.
The construction contractor should detail all lifting plates, padeyes and
others that are subject to dynamic impact stress, so that welds are not perpen-
dicular to the principal tension, taking into consideration that welds acting in
shear are much less sensitive to cracking than welds in tension.

C 150

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1

FIGURE 5.1 Grinding or machine tapering of the steel plate for welding penetration.