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Old 07-26-2011, 12:44 PM
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87hdrush 87hdrush is offline
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Join Date: Dec 2009
Location: fremont ohio
Posts: 218
Default does steel shrink?

well John I did the math and this is what i found, a peice of 18GA. 2' Wide x 6" long heated from 80 deg. to 500 deg. will expand .016" when heated to 1000 deg. it grows to .036 this is enough I should be able to measure the contraction after quenching in my shop. (won't be back in lab till the end of aug.) I'm going to cut a few test strips and see what happens. we know the metal shrinks the question is how much? there are so many varaiables in welding pannels the big question is how much does the weld bead contract after cooling? the math says if left to cool in still air a 6" bead will contract .109" A 1" bead only .018". I'll quench some test strips and post the results.

OK here's what happened. The 2" x 4" test strip didn't show much contraction at 500 deg. 3 heats and the shrinkage was less than .002 at about 1000 deg each heat netted .003 up to about .009 then tapered off. but here's the supprise when I heated the strip to an orange glow then let it cool slowly it contracted another .002! so much for text book learnin' From what I've found out here I'd say the sweet spot for the shrinking disk is between 800-1000 deg. I'm going to try this again in the lab under more controlled conditions and see what happens. My prof. builds race cars so he will probably like this experiment, going to send him an email now
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Ted Wise
Fremont, Ohio

Last edited by 87hdrush; 07-26-2011 at 02:23 PM. Reason: results
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