When I built my corral I used old oil field pipe. I purchased the parts and acted as a "gofer" for a local guy I paid to do the welding. I used the pipe and ¾" sucker rod.
Where the sucker and the pipe met, to ensure a good, reliable weld, he had these little bent pieces of ⅛" or so rod, about 2" long that fit around the sucker that he welded to the posts......probably available at the welding supply store just like caps for the pipe you weld on. You had a good welding surface on both sides of the sucker and made for a good reliable, easily administered, weld.
Work was done in 2005, worked some heavy, boystrous, cattle in it and no welds broken to date.