buttering. A surfacing variation that deposits surfacing
metal on one or more surfaces to provide metallurgically
compatible weld metal for the subsequent completion
of the weld. See also buildup, cladding, and
hardfacing.
surfacing weld. A weld applied to a surface, as opposed
to making a joint, to obtain desired properties
The definitions provided above is taken from AWS A3.0-2001 which are AWS terms and definitions.
Surfacing welds can be used to correct the dimensions of a joints, such as when the root opening is excessive. The weld is deposited on the groove face to reduce the root opening to comply with the requirements of the applicable prequalified joint detail.
Provided the base metal is listed in AWS D1.1, a matching filler metal is selected from table 3.1, and the other conditions of prequalification are met, i.e., the use of preheat, weld profile requirements, etc. the procedure can be written to include or to address surfacing. It is more expedient to meet the requirements of prequalification when time is of essence because no testing is required.
If the base metal is not listed in table 3.1 or if a matching filler metal is not used or one or more conditions of prequalification cannot be met, the alternative is to qualify the procedure in accordance with clause 4 of AWS D1.1. An alternative to qualifying in accordance to D1.1 is to follow the requirements of AWS B2.1 provided the EOR or the customer agrees.
If there is a need to qualify the procedure in accordance to AWS D1.1, you can qualify the procedure using a standard V-groove to establish the mechanical properties. Once the procedure is qualified, it can be used for surfacing welds as described in D1.1 for the correction of root oopenings per clause 5.22.4 (AWS D1.1-2010).
Best regards - Al