1018 is a low carbon steel, the only thing you could do with it would be to carburize it anyway, not worth the trouble. I saw the drawn cup and yes that's a good way to do it, that gives you a good bearing surface without any unknowns. The strength of the weld zone isn't very good, about 53ksi is what you can expect from normalized 1018, the area above the heat effected zone is good for about 70 ksi and that's probably ok given, as Jeff noted the loads are compressive anyway. If the bearing can handle the load then it should work pretty well. Not sure what the bearing loads are, but that's probably the life limiting factor on it right now. Within the limitations of the stock crank cases you've done about as well as could be done.