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Welding handbook 14.0 Avoidance of discontinuities in the joint

14.0 Avoidance of discontinuities in the joint
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Discontinuities, including different types of cracks, The standard EN ISO 5817 is a well-established
can occur during welding of every type of steel international publication. In this publication, the
including the Hardox and Strenx grades. The feature of the joint is divided into three different quality
discontinuities mentioned in this chapter can all levels. Level B has the most stringent requirements
occur during welding of various types of steel regarding the accepted levels of discontinuities. Level
including the Hardox and Strenx grades. However, C has a somewhat milder requirements and level D has
the steel properties of the Hardox and Strenx the least requirements in this respect.
grades do not have any particular sensitivity to these
discontinuities in relation to other types of steels. The discontinuities that are described in this
chapter are:

Some types of discontinuities can be called defects 4 Lack of root penetration
but the meaning of these two terms differs to some 4 Lack of fusion
extent. A discontinuity is an interruption of the 4 Solidification cracks
physical structure of the weldment. A defect, on the 4 Slag formation
other hand, is a discontinuity that causes the weldment 4 Undercuts
to be unable to meet the specified requirements of the 4 Crater pipes
structure. Consequently, a defect needs to be removed 4 Porosity
and corrected in a welded component while there are 4 Spatter
discontinuities that can be allowed in the structure.
This means that a certain kind of discontinuity is a Issues regarding hydrogen cracks are emphasized
defect in certain structures and in others not. for joints in high strength steel and this matter is
separately addressed in chapter 4.
This chapter focuses on:

4 A short explanation of different types of Counteracting magnetic arc blow is a general
discontinuities and how they occur. measure that is beneficial to avoiding discontinuities.
4Suitable measures to avoid each kind of Issues regarding magnetic arc blow are separately
discontinuity. The mentioned measures are described in chapter 15.
examples of preventive assessments that can
be made.
4Descriptions of the acceptance criteria for
specific discontinuities according to the standard
EN ISO 5817.

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