steel 4130

Wicks aircraft catalog gives two values for 4130:
min tensile (breaking) 95,000 and min yield (where it starts
distorting) 75,000. Usually the initial yielding will have quite
a bit of strength giving you a chance to get back down. But
repeated cycles will weaken it and rupture. Check the structure
for any cracks and fix it.

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Paul Lee, SQ2000 canard project: www.abri.com/sq2000

Philippe Vessaire wrote in message -moi...
Hello,

when I read 90,000 lb/sqi for strength,
is it just before the part is broken or is it the elastic limit?

Thanks