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Welding handbook 17.0 Repair welding of structures

17.0 Repair welding of structures
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Repair welding addresses separate types of issues in levels. When straightening of the structure is – or
relation to other welding operations. Repair welding might be – required, it is preferable that a suitable
is most commonly done to repair discontinuities from procedure is determined prior to repair welding.
a previous welding procedure or to repair a structure 4 The non-destructive evaluations to be made on
due to an earlier overloading. Matters related to these the welded structure are decided. This measure
two areas are described in this context. is preferably performed both prior to and after
repair welding in order to detect potential
If undesired discontinuities occur in the joint, or a discontinuities.
fracture appears in the structure, it is essential that the 4 New approvals of the structure might be
situation is assessed and that, if necessary, preventative required due to the repair welding.
actions are taken in order to reduce the risk of
reoccurrence. If unacceptable discontinuities are present; Repair welding procedures that are performed
it means that the original welding performance needs to indoors can be executed with all types of
be modified. For situations where overloading occurs, conventional welding methods. The original
appropriate actions like a reduction of load or improving welding method, in these situations, may be a
the design of the structure are essential.
good choice since the production equipment is
adapted for the specific structure. Outdoor welding
The assessment can, on occasion, show that the is mostly performed using the MMA welding
discontinuities in the joint – including potential process since it is very versatile. Examples in this
cracks – are not critical for the function of the respect are that:
structure. In these cases, it may be that repair
welding is unnecessary and that: 4 The MMA equipment can often be moved with
relative ease from one location to another.
4 Another operation, such as grinding off the
discontinuities, is the best solution to solve 4 It is feasible to weld with MMA welding in all
the problem. welding positions.
4 The joint can attain good properties during both
4 Additional measures are not needed at all.
indoor and outdoor welding.

17.1 The planning of repair welding The shielding gas related welding methods should
only be applied indoors. Outside, the shielding gas
If repair welding is performed, care should be taken can blow away during the welding process leading
to ensure that all requirements can be fulfilled for to an insufficient protection of the weld pool.
the structure. Outdoor welding also carries a greater risk for an
increased level of hydrogen in the joint during the
Examples of frequent issues in this respect are that: welding performance from substances such as
4 The requirements regarding the mechanical moisture, rust, grease and oil. This is because factors
properties in the joint shall be fulfilled. like dampness, rust, and contaminants in the joint
can be more difficult to control and eradicate during
4 Distortions formed during repair welding are outdoor welding.
considered. If needed, suitable counteractive
proceedings are planned for in order to reduce their

This handbook contains general suggestions and information without any expressed or implied warranty of any kind. SSAB hereby expressly disclaims
all liability of any kind, including any damages, in connection with the use of the information and for their suitability for individual applications. 101
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.