steel sizes

[southernford246]

what is the sizes in inches for 40x40x2mm, 30x30x2.3mm, and 20x20x1.6mm box tubing??

[Engineer]

To Convert from MM to inches divide by 25.4.

So

40x40x2 is 1.575 x 1.575x.079.

30x30x2.3 is 1.181x1.181x.091.

20x20x1.6 is .787x.787x.063.

The is no exact conversion, but the sizes are close to  1-1/2, 1-1/4, and 1"

.062 is 16 guage.

.074 is 14 guage.

.109 is 12 guage.

.120 is 11 guage.

[Engineer]

Those are common sizes, .19? is 13 guage, but I have not found many companies who stock 13 guage.

[southernford246]

so im gessing a 10 gauge is 1/8"

also what steel would you use a hot rolled or cold rolled? for box pipe and sheet steel?

[Engineer]

10 is actually .132 I believe.  11 is considered 1/8"

You don't have a choice of cold or hot rolled on the tubing.

Cold rolled is a better finish that hot rolled, but also more expensive.

We don't know your application for the steel, so it is hard to say which is better.

[southernford246]

fuel tank, side panles and floor pan

[SPEC]

I do
fuel tank... 14GA. Because of where I put them you could go 16 Ga. IMO 14 is a better choice...safer and easier to weld on
Floor pan ...16 GA. I roll the pan around the bottom of the cage so if won't hang and catch on obstacles
Body panels...18 GA. with cross braking and bends for strength works for me

[southernford246]

what is the difference between flats, plates, and sheet steel???

[Engineer]

The Thickness!

[SPEC]

Yup,
Sheets generally sto at 10 ga.
The it is dimentianal 3/16'' etc
Flats or flat stock are geneally flat stips of steel IE 1/4 x 4''

[southernford246]

ok what is the strongest of those 3 and cold rolled or hot rolled?

[Rick S.]

For the Piranha you want to use 1 1/2 sq. 14ga. for the upper and lower frames.
In tubing this will be (.083) wall thickness. For the 32mm you want 1 1/4 sq. 14ga.
For 20mm use 3/4sq. 16ga. (.065) Download a steel catalog from:
http://www.centralsteel.com/tube.htm 
The square tubing you want is on page 119.
For the roll bars use 1 1/4 O.D. x 12ga. DOM welded (page 99)
For all of your laser or waterjet work you want to use H.R.P.O. this is hot rolled pickled in oil.
It has a smooth skin like cold rolled and it's cheap. You may have trouble getting small sizes in HRPO it comes in large sheets. Whoever does your laserwork should stock it.  If you want smaller widths, use cold rolled flats. Hot rolled flats have a nasty scale.

[Rick S.]

If you're going to be bending it you want to use hot rolled. or hrpo
cold rolled will crack if bent to tight. So for a fuel tank you would probably want hrpo

[SPEC]

COLD ROLLED IS MORE DENSE AND UNIFORM
than hot rolled, it also costs more, and usually has some mill scale on it for tanks and skins hot rolled is fine

[Admin]

COLD ROLLED IS MORE DENSE AND UNIFORM
than hot rolled, it also costs more, and usually has some mill scale on it for tanks and skins hot rolled is fine

explain that a little better spec, it sounds like you say cold rolled has scale to it, I can say hot rolled sux to machine...