What Does Weld Cracking Mean?
Weld cracking refers to a depression left at the termination of a weld where the weld pool is left unfilled. Most forms of weld cracking result from the shrinkage strains that occur as the weld metal cools. If the contraction is restricted, the strains will induce residual stresses that cause cracking.
Weld cracks are potentially disastrous as they can give rise to high-stress intensities which may result in sudden unexpected failure below the design load, or in the case of cyclic loading, failure after fewer load cycles than predicted.
Corrosionpedia Explains Weld Cracking
Cracks that form in and around the weld can be distinguished into two main categories: hot cracks and cold cracks. Cracks that form during the cooling process are referred to as hot cracks and cracks whose formation is delayed are called cold cracks. Cracks can also form in and near the weld during use and can be caused due to fatigue or corrosion.
To identify how and why a particular crack formed, the weld design must be evaluated, crack locations identified and related metallurgy evaluated. Once the root cause or causes are identified, appropriated action can be taken to avoid crack formation.
Broad types of welding cracks include:
- Longitudinal crack
- Transverse crack
- Throat crack
- Underbead crack