Wayne: As for the quality of the welds, I can only say that they are better than what I can do. I believe that when welding cast material you're <u>supposed</u> to heat the whole piece up almost to the point where it is molten BEFORE welding on it, something about the intense heat of welding disturbing the crystalline structure of the cast material ya-da-ya-da.
As for your axle, I ran my 149 for years with an axle that was broken about the same distance for the pivot hole, but on the opposite side, near the grease fitting. The person who welded it (a community college instructor, I'm told) added a piece of flat bar on each side, across the "valley" of the I-Beam. On the grease fitting side, he cut out an angled semi-circle so that the grease fitting could be accessed. Unfortunately, his access "port" didn't allow my grease gun to get to the fitting, so I finally removed the axle and pitched it; otherwise I would share a picture of it.
However, the axle did not fail in service. I don't see where it would hurt to reassemble and try it out.
Edit: Judging from the color of the paint on my tractor, he may have used a torch to heat up the parts before welding on them.