1. The sketches in Figure 823-B* illustrate acceptable preparations for joining pipe ends by butt welding for materials having unequal wall thicknesses and/or with unequal strengths (minimum specified yield strength).
2. The thickness of the sections to be joined, beyond the joint design area, shall comply with the design requirements of this Part.
3. When the minimum specified yield strengths of the sections to be joined are unequal, the deposited weld metal shall have mechanical properties at least equal to those of the section having the higher strength.
4. The transition between ends of unequal thickness may be accomplished by taper or welding as illustrated or by means of a prefabricated transition ring.
5. Sharp notches or grooves at the edge of the weld where it joins a slanted surface shall be avoided.
6. For joining unequal thicknesses of equal specified yield strengths, the rules given herein apply, except there is no minimum angle limit to the taper.
7. THE MAXIMUM THICKNESS td FOR DESIGN PURPOSES SHALL NOT BE GREATER THAN 1.5t.
*ViaData Note: some versions of the code (incorrectly) reference "Figure 523-B".