Page 102 - SSAB Welding Handbook Edition 2

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17.0 Repair welding of structures Welding handbook

Additional measures should be taken in order to 17.2 Realization of the weld repair
reduce moisture pick-up during these situations:
©SSAB
The established weld discontinuities or fractures
4 During outdoor welding, the recommended are first removed. It is also beneficial to remove a
minimum preheat temperature is set to a minimum few millimeters or more beyond the point where
of 50°C above the preheat recommendations, the flaw seems to end, since part of the flaw can be
mentioned in chapter 4, when possible, or to at embedded in the joint and hard to find.
least 100°C. This is because enhanced levels of
preheating facilitate further hydrogen migration Arc gouging, grinding and thermal cutting are the
from the joint to its surroundings. The maximum most common methods of removal. If possible, the
preheat temperature is the same as for other kinds main part of the flawed material is separated with
of welding performances, described in chapter 4.
a highly productive process.
4 Outdoor welding is to be performed without
direct exposure to rain or snow. Arc gouging can combine a high efficiency with a high
4 During outdoor welding, it is especially degree of flexibility. This method is, therefore, often
important to handle the consumables in the best choice for the primary part of the process. As
accordance with their manufacturer. Preferably, stated before remove at least 2 mm of length beyond
new consumable packages should be opened the undesired metal, since discontinuities might be
just prior to welding in order to avoid excessive hidden in front of the arc. The experience from SSAB
moisture pick-up. is that preheating – in order to avoid hydrogen cracks
– is not necessary during arc gouging of the Hardox
When planning repair welding, it is beneficial to and Strenx grades. The recommendations for thermal
study the instructions and results from the original cutting are described in chapter 11.
welding procedure. A judgment can then be made as
to whether or not certain welding parameters from The next issue is to ensure that the weld area has a
these procedures can be utilized. This information proper and clean joint configuration. This implies
can be attained from earlier welding procedure that welding can be executed in the existing
qualification records (WPQR), welding procedure condition or that further joint preparation with
specifications (WPS) and similar documents. grinding and/or cleaning of the joint is necessary.
The repair welding procedure can then be carried

Welding in the horizontal position (PA) is generally out according to plan.
preferable whenever possible. The principal benefits
for this welding position in comparison to others are After completing the repair welding, the earlier
that: planned measures of non-destructive evaluations
are to be taken in order to ensure that the repaired
4 It enhances the control of the welding structure fulfils the required properties.
performance thus promoting high property
qualities in the joint.
4 The horizontal position typically permits the
highest degree of welding productivity.

102 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.
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.