A crack which develops after solidification is complete.

Cold cracking, commonly called delayed cracking, occurs some time after a fusion weld has been made and has fully solidified, often well after it has cooled to room temperature. The origin of this type of transgranular cracking is embrittlement of susceptible microstructure (most commonly untempered ferrous martensite) by diffusible atomic or nascent hydrogen in the presence of a tensile internal (i.e., residual) or applied stress. The fact that this type of cracking can take considerable time to occur gives it the name “delayed cracking.” See also UNDERBEAD CRACK and HYDROGEN EMBRITTLEMENT.

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