[Shiny]

Originally Posted by Brad_bb

One thing to watch for, wherever it’s been welded at the frame rail, look for spider cracks around the weld and that area of the frame rail. When we re-welded mine, we had to chase a bunch of spider cracks.. This tells me that the frame was heat treated somehow..

Feel free to ignore but I'm always interested in how stuff fails. Were these cracks in the weld material or in the frame? If in the frame, is it possible these cracks were already there and caused by fatigue, but the heat of the welding process caused them to open up or propagate? This would make some sense to me, given the need to repair was likely a result of fatigue failure.

I'll admit to being skeptical about a frame being heat-treated, given the size of it and the economics.

Does anyone know what alloy was used in these frames? I would expect a cold-rolled low-carbon steel, but I'm just guessing.

Mike

[Brad_bb]

The spider webbing cracks were in the frame emanating from the weld point. I’m sure they were from fatigue. The constant twisting of the frame, and as it proved, was not properly braced, thus the need for the braces late in production and in 65. I have no proof that the frames are heat treated, but I suspect they are. Stiffer frame with a lighter weight. I know that steel rims in the 50s were much softer than the steel rims in the 60s, and I believe they were either heat treated or a stiffer alloy. You can definitely tell the difference between my 55 Chevy steel wheels and mid 60s GM steel wheels. The 50s wheels are much more prone to deformation and damage.