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What causes longitudinal cracks in welds?

What causes longitudinal cracks in welds?

Longitudinal crack They are usually caused by high shrinkage stresses, especially on final passes, or by a hot cracking mechanism. Root cracks start at the root and extent part way into the weld. They are the most common type of longitudinal crack because of the small size of the first weld bead.

What causes longitudinal edge cracking?

The primary cause of this type of longitudinal cracking is the presence of highly plastic clay soils as the subgrade material and changes in the moisture content of these soils due to climatic changes.

How do you fix longitudinal cracking?


  1. Low severity cracks (< 1/2 inch wide and infrequent cracks). Crack seal to prevent (1) entry of moisture into the subgrade through the cracks and (2) further raveling of the crack edges.
  2. High severity cracks (> 1/2 inch wide and numerous cracks). Remove and replace the cracked pavement layer with an overlay.

What direction does a longitudinal crack run?

Longitudinal cracks run parallel to the direction the pavement was laid, and also aren’t usually load related—although if the pavement is heavily worn longitudinal cracking may signal more problems to follow.

What action must be taken if a crack appears in a weld?

The crack generally is directed down into the base metal, right at the weld toe. If you don’t create a smooth transition of weld metal to base metal, you can disrupt the flow of forces through the weld. Such a high volume of weld metal creates significant shrinkage forces.

What is longitudinal cracking in welding?

9 LONGITUDINAL CRACKING Longitudinal or centerline cracking, of the weld bead is not often encountered in mig welding. These are small cracks which appear at the end of the weld where the arc has been broken. Although small, these cracks are troublesome since they can propagate into the weld bead.

What causes longitudinal cracking in asphalt?

Longitudinal cracks are caused by a poorly constructed paving lane joint, temperature cycling, reflective cracking in a base layer, or volume changes in subgrade.

What are the general cases of pavement failures?

Some of the structural distresses which can cause failures in flexible pavements are:

  • Alligator Cracking of Flexible Pavements. Ad.
  • Depressions in Flexible Pavements.
  • Corrugations in Flexible Pavements.
  • Shoving.
  • Potholes.
  • Rutting of Flexible Pavements.
  • Swelling of Flexible Pavements.

How can longitudinal cracking be prevented?

Increased coarse aggregate content, use of aggregates with a low coefficient of thermal expansion, a moderate water/cement ratio, and proper curing can lessen the potential for longitudinal cracking.

What causes longitudinal cracks in asphalt?

What problem can result if the root opening of a weld is too wide?

Another weld flaw, excessive penetration (too much penetration into the weld joint), can very often lead to burn through. Causes: Excessive heat is the primary cause of burn through. Having too large of a root opening on the weld joint can also result in burn through.

What causes root concavity in welding?

Root concavity is caused by shrinkage of the weld pool in the through-thickness direction of the weld. This imperfection is frequently associated with TIG welding with the most common cause being poor preparation leaving the root gap either too small or, in some cases, too large.