A butt welding procedure is enough for buttering.
UNLESS
UNLESS
BUTTERING - ASME SEC VIII
UW-42 SURFACE WELD METAL BUILDUP:
Construction in which deposits of weld metal are applied to the surface of base metal for the purpose of:
(a) restoring the thickness of the base metal for strength consideration;
Or
(b) modifying the configuration of weld joints in order to provide the tapered transition requirements of UW-9(c)
UW-33(B) SHALL BE PERFORMED IN ACCORDANCE WITH THE FOLLOWING RULES:
(1) A butt welding procedure qualification in accordance with provisions of Section IX must be performed for the thickness of weld metal deposited, prior to production welding.
(2) All weld metal buildup must be examined over the full surface of the deposit by either magnetic particle examination to the requirements of Appendix 6, or by liquid penetrant examination to the requirements of Appendix 8. When such surface weld metal buildup is used in welded joints which require full or spot radiographic examination, the weld metal buildup shall be included in the examination.