I've welded a spring back together on a golf when it snapped. Was fine tbh, although it did have a LOT of weld, the overlap on the parts i welded back together was about 4 inches.

I'll admit i was unaware at the time that it made them brittle, but it did take FOR EVER to cool down cause i was welding at about 160amps both sides of the join in 2cm beads with similar gap between.

Nice to know it's not technically as dangerous as i thought after i'd done it lol.