Tig welding (GTAW, Gas Tungsten Arc Welding) is not a new process, and was developed in the 1940s. Good gas welding was pretty much made obsolete by GTAW, but how many airframes were gas welded prior to that? I daresay, in the hands of a good gas welder with an AB torch and proper filler material, most gun frame cracks can be repaired and re-heat treated.
Cracks most often propagate from a localized stress riser. A crack which shows up after case hardening likely existed prior to that heat treatment, but opened up on heat treatment. Secondary cracking from welding usually shows up in the HAZ (heat affected zone, between base and weld metal), and is directly related to either impurities, or inclusions in the weld (gas, slag) or improper post-weld heat treatment.
Welding is a normal process in manufacturing of steel and steel products. Entire departments in companies like Electric Boat, are devoted to developing weld procedures and procedure qualifications. If it were such a risky process, I doubt we would build submarines from rolled and welded rings, 44' (Ohio Class Trident) in diameter, and welded together to make a tube called the pressure hull.
If my customers were as skeptical of welding as you seem to be, I sincerely doubt I would have been able to pawn off $10 million worth of castings a year.
I'll buy every cracked high grade Parker frame you can lay your hands on. You can throw in all those cracked Winchester lever frames while you're at it.
Oh My god, you mean they weld new barrels into old breech blocks? Don't they blow up?
