- fused zone (weld metal)
- bonding zone (fusion line)
- base metal heat affected zone (HAZ)
Weld Metal
A mixture of base metal and filler metal (when
used) combined during the welding process.
Fusion Line
A line or zone where the temperature was just
under the melting point of base metal.
Heat Affected Zone
The area of the base metal next to the weld that
does not melt but is changed by the heat from
the welding process. In a way, this area is heat
treated by the welding process, that is,
its mechanical properties have been altered.