Types of bevels are shown below. When the roof face dimension is zero, the bevel produces a feather edge.
Types of groove welds include complete joint penetration (CJP) and partial joint penetration (PJP).
As the name implies, CJP welds fully penetrate the joint, making full use of the thickness of the base metal pieces. Therefore, and also because weld metal is typically stronger than base metal, CJP welds are typically stronger than the metal pieces they adjoin. CJP welds may be achieved by making the depth of bevel match the thickness of the base metal, or by leaving a gap, called a root opening (as shown in the image above).
Face reinforcement refers to any convex protrusion of a groove weld beyond the surfaces of its adjoining pieces. Even though face reinforcement results in a larger weld, it provides no increase in strength, because load path is through the portion of the weld that is in line with its adjoining pieces. In fact, too much face reinforcement may actually decrease overall strength by creating stress concentrations.
When the groove of a CJP weld is not completely filled with weld metal, it is called underfill, and the actual strength of the weld is less than the design strength.
