Lack of fusion (LOF)
Definition
A planar weld defect where the weld metal fails to fuse to the base metal or to the adjacent weld pass. Essentially a crack in the weld joint. Among the most serious weld discontinuities because it acts directly as a fatigue initiation site.
Related terms
- Hot cracking
- Solidification cracking or liquation cracking that occurs at elevated temperature during or just after welding. Driven by liquid films of low-melting impurity...
- 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...
- 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...
Explained in
- Weld and Manufacturing Defect AnalysisA planar weld defect where the weld metal fails to fuse to the base metal or to the adjacent weld pass. Essentially a crack in the weld joint. Among the most s...