Steel Pipe Classification

[lgsabr]

I had some samples of steel pipe tested. The pipe was supposed to be A53 (Grade B). The yield and tensil came out better than required (on all except for one) but the Modulus of Elasticity for each sample were 24,000ksi, 21,000ksi, 27,000ksi and 14,000ksi...all below what I would expect for steel and the last one is very low. Could this be a cast iron? I had planned on using this as faslework posts but am not liking what I am seeing in these results. Any thoughts?

 

[MiketheEngineer]

I would be inclined to use new material - used equipment of unknown origin is dubious at best. Maybe just use a Safety Factor of 4 or 5??

 

[redpicker]

How did you measure the modulus? As far as that goes, how did you measure the tensile properties?

If you are taking the modulus from the load/extension curve of the strip tensile specimen, the modulus is most certianly in error. For one, the extensometer is probably not percise enough for an accurate modulus determination, but more important is the alignment and geometry of the test specimen is not controlled well enough.

If you had cast iron, you would have very low elongation. If you met the elongation requirements of A53, it isn't cast iron.

If you are taking the taking the modulus from the load/extension diagram, and those are your results, I would question the tensile properties (tensile and yield) since those values are, in some cases, 50% lower than what you would expect, which would suggest to me that something went wrong with the tests.

It is kind of hard not to meet the A53 Grade B properties.

rp

 

[lgsabr]

Redpicker, thanks for the feedback. Attached is the test results, maybe these will help.

 

[redpicker]

OK, on your attachement, there is
#1-18" .429

Is that to indicate 18" diameter pipe with a wall of 0.429"?

Is this a case where you have some unknown pipe and you are trying to use it for something? If so, you need to get some chemical analysis tests done. Looking at the results for #4, I'd wonder if it was even magnetic. If you had the chemical analysis, that might help.

rp

 

[lgsabr]

Here are the chemical tests of some more samples. The strengths came out better on these tests but still lower than expected.