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BS EN 10210 s235 1.5mm 25*25mm SHS Good Enough?
clockwork - 7/6/07 at 03:12 PM

My steel delivery didn't arrive yesterday so I've gone and tried some more suppliers. Anyway I've tried to order some more but am running into my knowledge gap.
I was originally after BSEN10210 S275 J2H, but am struggling to find it.

I can get:
BS EN 10210 s235 1.5mm 25*25mm.
or
BS EN 10210 s275 (2.0mm) 25*25mm.

A rough calculation means that the difference in weight is about 33% (or rather a lot in my opinion).

Can you lot help me?
P.S. If you vote can you just let me know which and why.

Anyway, thank you all.

[Edited on 7/6/07 by clockwork]

worX - 7/6/07 at 03:21 PM

I haven't voted as I don't truly fit into the "I know what I'm talking about" group!
however, I know that most of the 7 type chassis are made out of what used to be considered 16gauge, and that was almost 1.6mm thick. I also know that there are no stress/fatigue issues in this size steel in these chassis - I also believe that at that size it is slightly over engineered (supposing good joints and good welding are also carried out), which brings to my "vote" Yes it should be absolutely fine to use 25x25 1.5mm (but this is all only in my opinion, and I am not a chassis builder anymore!)
and as for the 2.0mm walled one - this is an avenue that several scratch built builders take, just for the sake of the extra strength (and sometimes to make it easier to weld slightly thicker stuff) but it is not necessary, and yes it does weigh that much more!

hth
Steve

flak monkey - 7/6/07 at 03:26 PM

Your BS EN 10210 is just the tolerance standard. S235 is the strength grade and its just bog standard stuff.

1.5mm is fine and is still overkill in some places.

David

[Edited on 7/6/07 by flak monkey]

Alan B - 7/6/07 at 03:26 PM

Exactly right...but did you add the SHS bit on?.....I don't think it's considered SHS as such...more like ERW square tube..

MikeR - 7/6/07 at 03:30 PM

not voted but i went to metal supermarket and said,

" i want some 1" 16 gague (or what ever 1.6mm is) RHS ERW steel"

They said,
"you don't know what youre asking for do you!"

and i said "no, i'm building this space frame for a car and thats what i've been told to ask for"

They said "ok, we know what you want". The next day a lorry turned up with lots of steel on it.

clockwork - 7/6/07 at 03:30 PM

SHS, Square Hollow Section, my fault sorry. the title was getting HUGE :-)
Some people refer to it as RHS.

Alan B - 7/6/07 at 03:38 PM

I knew what you meant re SHS/RHS...it just is the wrong terminology for the smaller thin walled sections...usually they dont start until 2mm WT.....although things could have changed since I last lived in the UK

Aboardman - 7/6/07 at 03:38 PM

quote:
Originally posted by clockwork
SHS, Square Hollow Section, my fault sorry. the title was getting HUGE :-)
Some people refer to it as RHS.


RHS is Rectangular Hollow Section.

clockwork - 7/6/07 at 03:39 PM

Alan B - You are probably right... seeing as I have no idea
Learning is a vicious circle, the more you learn; the more you know you don't know; that you have to learn to find . . . wash, rinse, repeat ad infinitum.

[Edited on 7/6/07 by clockwork]

Alan B - 7/6/07 at 03:47 PM

The main thing is you will be getting the right stuff.....
We could discuss terminology all day, but it will not get your chassis built any quicker...

Good luck

Alan

mcerd1 - 7/6/07 at 04:46 PM

quote:
Originally posted by flak monkey
Your BS EN 10210 is just the tolerance standard. S235 is the strength grade and its just bog standard stuff.

1.5mm is fine and is still overkill in some places.

David

[Edited on 7/6/07 by flak monkey]


I don't actually know what's required for the car, but structural steelwork is my job so....

first of here is a link for you with loads of useful engineering info: http://www.roymech.co.uk/Useful_Tables/Matter/Steel_Europe.html

SHS = square hollow section
RHS = rectangular hollow section
CHS = circular hollow section

as flak monkey says S275 / S235 are the grades and BS EN 10210 is the standard they are made to

both parts are important if you need the strength

Standards
three main ones you'll see: (no including seamless tube)

1 - BS EN 10025 - plates, flats, angles, channels....
2 - BS EN 10210 - Hot Finished hollow sections
3 - BS EN 10219 - Cold Formed hollow sections

The main difference between hot finished and cold formed sections is that cold formed ones are not annealed after they are bent into shape.
This means that there is a bit more residual stress in the steel before you do anything to it and also the corners have a bigger radius (which means its not quite as stiff) also corus and so on don't recommend you weld at its corners

so for tube you best stick to BS EN 10210 (or seamless)

Grades
The 'S' means its a structural steel and the number is the nominal min. yield strength in N/mm^2
again three main ones available:

1 - S235 - European mild steel, cheep rubbish
2 - S275 - British mild steel, a bit better and still cheep
3 - S355 - British & European High Yield steel, a bit more expensive (and slightly more brittle)

If you did get high yield you'll need to check you welding wires suitability (otherwise your welds will be the same strength as the mild steel - which makes using high yield a waste of money)

Subgrades
The last part that every one ignores, but you shouldn't.
after the steel grade there should be a letter/number code - the most common are:

for all hollow sections = J0H or J2H
for plates etc = JR, J0, J2, K2 (may also have a G3/G4 code)

This relates to the quality/ fracture toughness of the steel - if it doesn't have this code on the paperwork then its not been tested

JR = room temperature
J0/ J0H = 0 deg Celsius
J2/ J2H = -20 deg Celsius
K2 = equivalent to -40 deg Celsius

the better the steel, the lower the temperature it can pass the test at, and therefore the tougher the steel for your chassis - I'd always go for J2H (most common anyway - but cheep steel won't be tested)

to sum up there are allot of variations in ultimate strength and toughness - but they all weigh the same and they all have the same stiffness (for the same x-section at least) - if it was me I'd go for the strongest + toughest one I could get, and gain a bit more safety for no extra weight

-Robert

clockwork - 7/6/07 at 05:37 PM

Thankyou all for your responses.
I'm going to go for the BS EN 10210 s235 1.5mm.
mcerd1, while I agree with you 100%, I can't get hold of the grades you talk about (you'll note I say "I can't" Not only that I'll struggle to get the mig welding wire too.
If you know any suppliers in the Plymouth/Devon/Cornwall area U2U me (or post them here) :-)

I intend to do a torsional stiffness analysis once built, so really need to know what I'm working with to post anything meaninful here.

Once again, thanks chaps.

mcerd1 - 7/6/07 at 06:16 PM

Avalibility of the steel I want is a constant pain at work
but I'm dealing with SHS sizes beween 100mm and 350mm

but then you wouldn't want to use 25x25x1.5 for the structures that supply power to your house would you
(literaly if your anywere near langauge ?)