Welding Inspection & Metallurgy API ICP Self Study Notes

Weld restraint induces stresses that can contribute to cracking of both the
weld and base metal in fabrication welds. This type of cracking occurs when
the rigidity of the joint is so severe that the base metal or weld metal strength
cannot resist the strains and stresses applied by expansion and contraction of
the weld joint. Weld restraint cracking specimen are designed to permit a
quantitative variation in restraint under realistic welding conditions so the
contribution of the weld metal, base metal and welding processes can be
evaluated with respect to contribution to cracking.
Typical weld restraint test methods include;
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the Lehigh restraint test,
slot test,
rigid restraint cracking (RRC) test, and
circular weld restraint cracking test.