Ah, its nice to deal with someone who knows what I'm talking about. I have gotten into arguments with people who insist that stress risers from arc welds don't exist.
One of those guys and I were standing next to a piece of steel that had 8 welds in it one next to the other, it having broken next to the previous weld 7 times over a year or so.
He assured me that I was full of it, and stress risers were a myth. When I asked about the 8 welds, all of which he had done, he told me that heat stress had nothing to do with it, and that sometimes steel just broke next to a weld.
The guy who owned the steel asked me if I could stop it from cracking again because he was getting tired of paying this guy to weld it.
I said sure, I let the original guy weld it, he was actually a darn good welder, then grabbed a torch and went to work.
It never cracked again.
Since you understand heats, I'm not concerned. But don't sell those old frames short. Not sure how much carbon they had, but I have seen older frames cracked next to welds before.
You heat and quench them, they might get harder than you would expect.
I suspect that with the long runs, there was plenty of time for the heat to spread even it it wanted to harden.
Usually when I see a frame crack next to a weld, its when a fairly small but hot weld was done like welding a right angle brace on.
The area of the weld got really hot really fast, but then the welding stopped, and the mass of the frame quenched the heat quickly.
Few months later, you start seeing stress cracks around the weld.
BTW, I forgot to say, it looks nice. Just try to keep it out of the tank traps this time..........
