There actually isn't any weight savings compared to 1020 steel for the frame.
1020 and 4130 still have the same modulus of elasticity so for the same "I"
value
the bending stiffness is still the same. Where 4130 can gain is with the
bending strength.
But the rules say we need to have equivalent to bending stiffness and strength
to 1"X0.083.
I like to use 1020 DOM 1 1/4"X0.049 because it is a lot cheaper...
Anyway, getting back to you question about heat treating, I've read that for
thin wall tubing such as these frames (I hope your not using anything .120"
thick) that heat treating/stress releaving is not required:
http://www.lincolnelectric.com/knowledge/articles/content/chrome-moly.asp
However, if you still want to do it, this is a good article on how to do it:
http://archive.metalformingmagazine.com/2001/01/Lincoln.pdf
Hope this helps.
James
University of Michigan - Dearborn
-----Original Message-----
From: Paterson S [mailto:paters6@uwindsor.ca]
Sent: Wednesday, October 08, 2003 9:31 AM
To: mini-baja@autox.team.net
Subject: 4130 Steel
Hey guys,
I know some teams last year used chrome-moly steel for
their roll cage. I understand that we can save a lot of
weight using this type of steel as it can maintain the same
strength as plain carbon steel however using a thinner
tubing. My question is, is it really necessary to
post-weld heat treat? I have read in some books that it
would be stupid not to do this because the weld will become
brittle and can crack without heat treatment. However, I
have also read that it is not necessary. Does anyone have
any thoughts or commments on this? I would really
appreciate it.
Thanks,
Sarah Paterson
Team Manager
2004 Midwest Mini-Baja
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