Taylor CD-MULTIGUN, Руководство по эксплуатации

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V - 21A
21
WELD ASSESSMENT / TESTING
Visual examination of weld quality can, even with limited experience, pro-
vide a useful quality assessment. In such a check the presence of a small even
witness of weld material around the base of the stud flange after welding
should be ensured. Poor welds are indicated by excess metal on one side of
the welded flange and / or the presence of an undercut or non
- fused area be-
tween the stud flange and the parent sheet or plate. Incorrect settings, ad-
verse magnetic effects etc. such as those at edge welding positions or with un-
balanced earths and studs welded to the work piece at an angle, the controller
and pistol should be examined with a view to correcting such defects.
MECHANICAL TESTS :

BENDING.
The most easily applied method of testing the quality of welded fasteners
considered here, involves the use of a bending bar. This bending bar (available
from your supplier, see the accessories section of this manual) fitted with the
correct size of nozzle for the stud to be tested is used to bend over the stud in
accordance with the BS EN ISO 13918 specification .

TORSION.
A torsion test provides useful information for threaded fasteners. This in-
volves tightening a nut on the stud against a spacer, suitably relieved to cater
for the flange and weld spatter. For quantitative assessments a suitably cali-
brated torque wrench may be used, but at its simplest, a spanner will suffice.
In the above tests the performance of the welded joint should be consid-
ered in relation to the thickness of the material to which the stud is welded.
On thicker materials, a full strength weld is denoted by deformation or failure
of the stud shank. On lighter gauge material, severe "dimpling" or "dishing" at
the reverse to the weld side normally indicates sufficient strength, whilst in
most cases, the tearing of a slug of material from the parent sheet will occur.