Welding Inspection & Metallurgy API ICP Self Study Notes

Hot cracking
These cracks are known as hot cracks because they
occur immediately after welds are completed and
sometimes while the welds are in progress, when the
weld metal tends to solidify from the corners of the base
metal to which it is joined. There are 2 major reasons
contributing to hot cracking;
• As the solidification proceeds, the low melting eutectics are
concentrated in the center and remain liquid, which is then torn apart by
the stress associated with the welding, resulting in a center line crack.
• Hot cracking occurs when the available supply of liquid weld metal is
insufficient to fill the spaces between solidifying weld metal, which are
opened by shrinkage strains.
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