4130 Normalized, I presume, is great for racecars (very high strength to
weight ratio as compared to most mild steels) but it's springy and work
hardens, It should only be TIG welded and stress relieved any place it's
welded or bent. I wouldn't use it in your application. If you decide to
stick with round tubing use 1020 DOM. It is almost as strong as 4130 and
tuff as hell plus it can be welded with a MIG. Hope this helps.
Steve
"Albert Allen"
wrote in message
news:FFDD17FA47507A26A21B3039689F73F7@in.WebX.maYIadrTaRb...
> A simple yet complex question for all you P.E.'s or anyone else that want
to
> give it a stab..........Pound for pound which is stronger for a vehicle
> frame, round or square tube?
>
> Here is the situation:
> We have always built square tube frames for our Sno-Cat's but recently
have
> been working with 4130 round tube frames. We are trying to get vehicle
> weights down and although we have saved about 100 pounds using round tube
> over square (no big deal on a 7300 pound machine) we have also added 16
man
> hours per frame in the process and we are starting to see some slight
joint
> cracking in the round tube frames (which we have never had with square)
>
> As you can tell I am biased toward the square tube frames but as one of
our
> salesmen pointed out, "all the race cars use round tube frames and they
have
> no problems"
>
> Any advice would be greatly appreciated and pardon the non Inventor
related
> subject but this is where all the brains are
>
> Thanks
>
>