certified roll cage

mopar4406bbl said

The NHRA tech guy told me that a stick welded cage is not suppose to pass certifaction, but You can go over stick welds with tig or mig weld.I can live with that. What suprised me most, was everything track tech told me about cage was wrong.The NHRA tech guy is going to be at local track in 3 weeks,hope to have welds gone over by then and see what happens.

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While going over the welds might make them look kosher, the heat sinking will only be made worse. Chrome-moly has a higher carbon content than mild steel, and at high temperature the carbon migrates and localizes at the weld, making it brittle. Repeated heating will worsen this effect, increasing the chance of cracking at the welds.

As mentioned above, TIG welding limits the area exposed to heat, reducing the amount of carbon that can be pulled into the weld. If you only expose a quarter inch of metal to high temps, then only the carbon in that quarter inch can migrate. Expose an inch of metal, all the carbon in that inch can migrate to the weld. And if you expose the same metal to high temps several times, you will end up with migration each time, resulting in more of the carbon getting closer to the joint.