Stress Strain Curve For G550 Steel (cold form) Austrailia

[Parrapit]

Hi All

I need to manually enter a stress vs strain curve for steel material G550 apparently it is mostly used for cold formed sections. Because of its min BMT (base metal thickness) of 0.42mm it does not comply with South African standard of min 0.5mm. It is under amendments. However as things stand at the moment I need to check this material in a roof sheet. So maybe some Australian guys can help me out with the properties for this material. I have found some properties but would like confirmation and the ones i have not found.

Material G550 Steel 0.42mm (BMT)

Fy = 550
Fu = 550 (fy/fu=1)
Density = Unknown
Modulus of elasticity (E) = Unknown
Possion's ratio = Unknown
Expansions coefficient = Unknown
Stress VS Strain = Unknown

For the stress VS strain need a Max Stress(550) vs strain (unknown) and a min Stress(-550) VS min strain (unknown).
Both min and max should be the same.

Hope it makes sense.

 

[jayrod12]

I'm gonna throw this out there but it may be wrong (Materials class was the bane of my degree, could've been the teacher but only a bad carpenter blames his tools)

Since steel is steel the modulus is still 200 GPa, since poisson's ratio is dependent on E I would again assume it is the same regardless of the steel used. The stress versus strain curve would then look the same for this steel as any other steel with the same Fy/Fu values.

I also thing the expansions coefficient should be the same.

Again, could be completely off on those assumptions but that's how I remember it.

 

[dhengr]

Parrapit:
.42mm is more like foil than it is like coil steel or sheet mat’l. That is likely pretty seriously cold worked in the rolling process and/or forming process. I don’t know that particular grade of mat’l. But, it probably started out with a pretty normal stress-strain curve, but with Fy approx. = Fu, you are working high up on the curve, in the strain hardened range. When you load the mat’l. it will follow the normal stress-strain slope, but it finally hits the curve right up near the ult. strength, and fails. You no longer see a yield strength or yield point. I would go the mat’l. supplier or the mat’l. manufacturer for the info. you want.

 

[hokie66]

Parrapit,
.42mm is a typical base metal thickness for steel roofing and cladding sheets in Australia, not cold formed sections. Steel is steel, so jayrod12 is correct...the slope of the stress-strain curve is the same regardless. I don't know why you should be concerned with the post-yield part of the curve.

http://www.lysaght.com/

 

[saplanti]

Here is the product brochure that you can reach the standard name and other details.
Hope it helps.

 

[saplanti]

The attachment gives densities. If you need further information you need directly contact BlueScopeSteel.

 

[Parrapit]

Thanks Guys.

Just to some up. As far as I know the Modules of elasticity (200) is the slope of the stress strain graph so if this mat is the same as the 200 then I agree the stress vs strain graph should look the same (have same slope) and the strain will increase or decrease all the same as the stress increases or decreases.

However I don't agree that the modules of elasticity is the same for all steel which in affect will change the slope. But the difference between the E values of different steel is minimal and therefore can be assumed to be the same.

In SA we have 350w grade with 206 E and S355JR which is 200 E. Which does not really affect to much.

As far as I know as well the 200 E is +- 200 or approximate E and not an actual E value.

 

[hokie66]

If you are looking for a more exact figure for E than 200000 MPa, you are kidding yourself. Of all the variables we use in structural design, this one is the most like a constant. For instance, yield stress varies by a lot.

 

[saplanti]

If you are using this material you need to get the values from the referenced standards in the documents above. Unfortunately, we do not have sufficient financial ability to obtain all the standards to provide you here. Please this is cold formed high strength material. Yield and tensile strength are close to each other.
If you are going to provide and FEA analysis you had better contact the material manufacturer. They are really friendly to answer your questions. Send an e-mail, and get your answer instead of struggling in the forum which will not take you anywhere. You can even use their reply as an evidence for your calculation if necessary.

 

[Parrapit]

Thanks Saplanti

I did. But I would not say that the forum does not help, confirmation is more what I was looking for, which I got, so thanks guys keep posting I love this forum.