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Welder’s Handbook
Cracks
A tear, fracture or fissure in the weld or base metal appearing as a broken, jagged or straight line. Cracks are the most serious defect and are prohibited by industry standards.
Crack Types
Crack Types
Cracking can develop in the weld, heat- affected zone (HAZ), or base metal when localized stress surpasses the metal's ultimate strength. These cracks are categorized as hot or cold and may be longitudinal or transverse in their orientation. Hot cracks, also known as centerline or solidification cracking occur immediately after welds are completed and sometimes while welds are being made. Cold cracks, also known as delayed cracking or hydrogen cracking occur after the solidification of weld metal. Cracks are classified according to their location in the weld. Crack types in welds are throat cracks, crater cracks, transverse cracks, underbead cracks, lamellar tearing, toe and root cracks, fissures, and liquid metal embrittlement.
CRATER CRACK (HOT CRACK)
TRANSVERSE CRACK
LONGITUDINAL CRACK
UNDERBEAD CRACK (COLD CRACK)
TOE CRACK (COLD CRACK)
ROOT CRACK (HOT CRACK)
Most Common Types of Cracks
Hot Cracks
Crater Cracking:
Hot cracks, also known as centerline or solidification cracking occur immediately after welds are completed and sometimes while welds are being made.
Hot cracking mainly caused by a failure to fill up the crater depression at the end of a weld pass. Shrinkage stresses and inadequate weld metal in the crater causes crater cracking. Cold cracking that is usually in the Heat-affected zone (HAZ) of the parent metal Usually a hot cracking phenomenon. Cracking runs along the length of the weld.
Cold Cracks
Underbead Cracks:
Cold cracks, also known as delayed cracking or hydrogen cracking occur after the solidification of weld metal.
Longitudinal Crack:
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