Car fire, chassis total loss or stress relief fix????

Samco Fab

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I look at pictures of Kory Sheelers TT burned, and have looked at a couple of other class 1 cars that burned to the ground.

It makes me wonder if the 4130 chassis was not excessively warped out of shape or cracked if it could be stressed releaved post burn and be as good if not better than before??

I know that a number of TT's out there have been oven stress releaved. What tempeture is this done at?

My initial thought is that unless the tube is melted and deformed, it should be able to be re heat treated with a stress relief process and be good to go.

Welding gets the tube much hotter than a fire, the stress relief process is a controled heating and cooling, would it take out any brittle localized heat treatment from water or fire retardant sprayed on a burning wreck??
 

Random Thoughts Racing

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Im no expert at chasis rererections, but perhaps if a chassis were built on a specific jig (or otherwise verified) beforehand that it could be precisely rechecked for "squareness" after a fire to to confirm all critical geometry.

If a chassis can be cost effectively reserected after a fire then it begs the question if a heat (or cryo) treatment beforehand wouldnt be prudent for added safety.
 

jsallenbach

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I think the best would be to contact a Heat treatment place and ask them, or contact a metalurgist (SP).
 

Ziggy

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Tim at Morgans Machine and Marine in Walnut Creek(speed shop) is a racing guru and a metalurgist.
Ph 925 939 7346
 

phatford

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Even if the fire were not too hot.... It would have been cooked very uneven and this is where you run into stress problems. One part tempered the other not and Boom Crack. Are you going to trust your life in a cage that may fail? To what save 20K at the most? Life.... 20K???? hmmmm

If this were something you didn't go out and drive 100mph in then fine probably could get away with chasing cracks forever. But for a race truck not a good idea.
 

weldithot79

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I have dealt with stress relief of chrome welds for quite some time now and some of the variables change with the different alloys but GENERALLY speaking 1 1/4 chrome is not heat treated under .375" thick weldments. Anything above that thickness or chrome alloys from 5%-9% are taken to 1400 Deg F, unlimited ramp up rate to 600F then limited to 400F per hour ramp rate. Hold time at the soak temp is determined by thickness generally one hour minimum and another hour for every additional inch of thickness. The cool rate is no more than 400F per hour until you get below 600F then it is unlimited again but GENERALLY left to cool on its own with insulation still on the heating blankets. This is for local stress relief of large weldments in industrial applications but the principals are the same as the grains structure sdoes not change until you are between the 600f-1400f range. I also wouldnt trust the frame with my life, unless you can get it in an oven for a proper stress relief. ON second thought take and have the hardness tested where tha fire was the hottest, that will give you a good indication of how hot the material really got and what condition the material is in,ie if it has become hardened from the heat. Any good NDE shop, such as TEAM industrial, will have a hardness tester and can tell you if the material is within spec.
 

Mark Newhan

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Judgeing by the pictures I would think that the fire was not all that hot. The front wheels and the shocks were intact (the aluminum). I agree, check the chasis on a surface plate and inspect it carfully, perhaps mag it. If the fire got to far above the heat treat temp you may have an issue.
 
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