Hot Cracking
Definition
Solidification cracking or liquation cracking that occurs at elevated temperature during or just after welding. Driven by liquid films of low-melting impurity segregates at grain boundaries, not hydrogen-related.
- Also called
- Solidification or liquation cracking
- Timing
- During or just after welding, at elevated temperature
- Mechanism
- Liquid films at grain boundaries from low-melting segregates
- Not related to
- Hydrogen embrittlement
Common questions
How does hot cracking differ from hydrogen-induced cold cracking in a weld failure examination?+
Hot cracking occurs at high temperature during solidification, driven by low-melting-point impurities forming liquid films at grain boundaries, while cold cracking develops later at near-ambient temperature and is driven by trapped hydrogen and residual stress, so the two require different remedies.
Which weld or base metal conditions make hot cracking more likely?+
High levels of sulfur or phosphorus in the base or filler metal, high restraint during welding, and certain alloy compositions prone to wide freezing ranges all increase the risk of liquid films persisting long enough to crack under solidification shrinkage stress.
Related terms
- Hydrogen Cold Cracking (HCC)
- Delayed intergranular cracking in the heat-affected zone or weld metal, caused by atomic hydrogen absorbed during welding, susceptible martensite microstructure, and residual...
- Lack of Fusion (LOF)
- A planar weld defect where the weld metal fails to fuse to the base metal or to the adjacent weld pass. Essentially...
- Laminar Tearing
- Step-like fracture in the base plate beneath a restrained weld, propagating along planes of MnS inclusion stringers aligned with the rolling direction...
- Phased-Array Ultrasonic Testing (PAUT)
- Advanced ultrasonic inspection using a multi-element probe whose beam angle and focal depth are electronically controlled to scan a weld volume systematically....
- Porosity
- Gas-filled voids in weld metal or castings, spherical or elongated (wormhole/piping), caused by dissolved gas evolving during solidification. Reduces cross-section and acts...