A couple points of interest regarding A706: The carbon equivalent is controlled so as to not exceed 0.55%, so under normal conditions, no preheat is required for commonly used bar sizes (up to #6). Typically, embedded attachments are designed so that they must develop the full tensile capacity of the rebar, so, a minimum weld is required. The weld of the rebar to the base metal must consequently be welded to develop at least the same strength. In lap joints, the minimum lap length required to develop the rebar is as follows: #3 = 2", #4 = 2 1/2", # 5 = 3", #6 = 3 1/2", # 7 = 4 1/2", # 8 = 5". The minimum (flare bevel) weld (E) = 5/32 db. For butt joints, the minimum fillet weld to rebar diameter required to develop the rebar is as follows: #3 = 1/4", #4 = 5/16", #5 = 3/8", #6 = 7/16", #7 - 1/2", #8 = 9/16".