The joint design incorporated into an application depends on the performance requirements of the part.
Parts requiring a structural weld can use a flat-to-flat or flat-to-groove joint design.
Parts requiring a hermetic seal that must withstand high internal pressures will use a tongue and groove joint design.
The symmetrical tongue and groove and step joints can be considered for applications with geometrical restraints.
The most common joint design, the tongue and groove, is also the most versatile.