1. The torque wrench is only an indicator. Lotsa guys tighten them without
a torque wrench (including yours truly). When it was getting that tight without
a click, your suspicions shoulda kicked in. BTW I use an indicating torque
wrench, the Craftsman cheapest kind so you can watch the needle while you
tighten and don't overshoot. Admittedly it isn't much help in the dark, but...

2. I would NOT weld a balljoint. They are made out of a steel that would
need to be heat-treated AFTER welding, plus you'll probably at least melt the
grease out of it and maybe the boot also. You will have a brittle heat affected
zone. Get the old bolt out with whatever it takes and then put it together
right with a new bolt. You don't need a broken ball joint upon hitting an
unexpected bump somewhere. I've had one, fortunately upon pulling into a
parking space, so there were no injuries but I shudder to think of what could
have happened if it had broken 30 seconds earlier on the highway.

BTW I am a professional metallurgist and welding engineer, Stanford '62
--
George Downs, Bartlesville, Oklahoma, Central US