Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

IRON PIPE Chemical Composition (no Carbon?) - Help determining type of Iron please 3

Status
Not open for further replies.

AntonioCP

Mechanical
Nov 18, 2021
4
0
0
US
Hello,

I have an SGS laboratory analysis report(image attached) of some Iron Pipes (see photo), for which I am trying to determine the type of iron. The SGS laboratory analysis does not indicate the Carbon percent... Is this possible, or must this be an error by SGS?

Could someone help determine what type of Iron (Cast, Iron, Ductile Iron, or other) does the chemical composition shown in the SGS report attached represent:
SGS_Redacted_yjsuid.jpg


Thanks in advance for your kind help with this.
Antonio
 
Replies continue below

Recommended for you

You can't measure C with xray, they need to do OES or combustion analysis to get you a C.
And in plain steels that is really what matters most.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
They did a PMI test, which is another name for X-ray fluorescence. XRF is NOT chemical analysis.

Reporting all those numbers is at least ignorant and at most dishonest.

Then they did NOT report the ONE thing PMI can actually tell you: the alloy ID. (Although with carbon steel or iron that will not narrow it down at all.)

They probably charged you almost as much as for actual chemical analysis. Sadly this is the norm for inspection companies, who have overhyped XRF to the point that their clients believe it is equivalent to chemical analysis.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
Thanks very much for the fast response.
Can you recommend best and least expensive way to determine what type of iron (Cast, Iron, Ductile Iron, or other) these iron pipes are?
This may not help, but here are a couple of pictures:

WhatsApp_Image_2021-10-18_at_12.50.33_AM_ltnmmr.jpg


Thanks again!
 
That is a serious mountain of pipes! Did somebody abandon a cross country project after procuring all this?

Every piece lacking traceability must be fully tested to certify conformance to whatever code you want to use it for (API?). This means tensile testing and exact composition at a minimum. Do it at a qualified laboratory, and for your own protection have a recognized 3rd party entity witness the sampling and testing (however it works in your jurisdiction AND the destination jurisdiction). Do you know the mill(s) it came from?

What you can do yourself immediately is look for any longitudinal weld seams. The colour of the material after grinding will tell you if it is steel or cast iron (gray or ductile), but CI is not very likely. Weld seams will of course rule out CI.

Good luck!

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
Have samples tested by Optical Emission Spectrometer.
All that you really need are C, Mn, Cr, Si.
That will let you nail down a composition.
You would need other tests (microstructure and tensile) in order to figure out how it was made.

Is this scrap that will be melted?
Of will this be cut up and used for other things?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
thanks again for all the replies.
This is scrap that will be melted and reused.
I will digest the information received and come back with more answers and probably questions.
Thanks!
 
If you have to check all this material in order to be melted PMI is the choice. If want to have a precise chemical composition, you have to look for others methods as mentioned above
 
isoca speaks truth.

Sorting scrap is a major sector for PMI intruments.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
AntonioCP said:
Could someone help determine what type of Iron (Cast, Iron, Ductile Iron, or other)

Composition is not the way to determine this. Instead, you need to look at the microstructure of the pipe and determine the graphite form. You can replicate the surfaces to look at structure if you do not want to send samples for metallographic cross-sectioning. You can do most of the characterization using the as-polished structure, though you will have to etch if you need to know whether the matrix contains pearlite. In particular, looking at the graphite flake morphology (flakes versus globules for gray vs. ductile) should be a huge help in characterization.

Beyond this, note most cast irons are not characterized by composition or only have token limits. However, many are characterized by tensile properties (especially ductile) and have tensile requirements for specific grades.
 
I continue to be very grateful for all the information received in this forum. We are looking for ways to resolve our questions based on the information you all have given. I will post results here when we get to that point.
Thanks.
 
mrf,

No metallography required.
As I said, cast iron can be differentiated from steel visually by just grinding to clean metal. Actually the spark pattern is another good way to differentiate basic alloy groups if colour doesn't do it.
Carbon steel can be differentiated from low alloy and stainless steel with just PMI.
A little residual alloy content may or may not be objectionable.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
Do an online search
spark testing steel chart

You will find lots of useful guides on figuring out roughly what C level you are dealing with.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
You also needs to know how to use an angle grinder and read the spark pattern and color. From the photos this looks like seamless tubing standard weight plain end bevel which would already be low carbon steel. SAE grade 1020 is typical with your stated Mn analysis. Carbon on SAE 1020 ranges 0.18 to 0.23.
 
Steel Gal,
Appreciate your sharp eyes. TThe rim of those pipes shown indicate they are carbon steel. There could be others that are spun cast.

 
Thank you for your kind words. It helps if you actually made the product as I did years ago in the Pittsburgh, PA area. I was a turn foreman for a now defunct steel company shipping this type of product by flatbed truck, rail, and barge on the Ohio River.
 
Hello,

you could give a try to Spectrum analysis and also if you are available to reach university labs. SEM or EDS even XRD could help.
Also you can try to collect mechanical tests results for comparison.


br.
 
I envy the eyesight of anyone capable of determining from these photos that all the pipes are seamless and also that they are steel. I thought that kind of photograph interpretation was only possible on the X-files.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
I live on a different street:
OES Optical Emission Spectroscopy
XRF X-ray Fluorescence Spectroscopy
PMI Positive Material Identification
SEM Scanning Electron Microscopy
EDS Energy-Dispersive X-ray Spectroscopy, also EDX or XEDS
XRD X-Ray Diffraction analysis


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
You've just filled your Acronym Bingo card.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
Status
Not open for further replies.
Back
Top