Steel grades AISI 1526 vs API 5L-X42
Steel grades AISI 1526 vs API 5L-X42
(OP)
We have a condition where we specified API 5L-X42 pipe for a billboard column and the client would like to increase the height. We asked for mill specs of the pipe to verify strengths and the client could not produce any. So we had the pipe tested. The test showed acceptable tensile and yield strengths, but the elongation in 2" was only 12.5%.
We then asked for a chemical analysis of the steel, and the testing company gave us the chemical composition and noted that it meets AISI Grade 1526. I don't know anything about this steel grade.
The client understands that we cannot increase the height without some reinforcement, and we intend to design this reinforcement if possible.
Can anyone explain what issues I will have working with the AISI 1526 instead of the API 5L pipe? Any suggestions on addressing these issues?
We then asked for a chemical analysis of the steel, and the testing company gave us the chemical composition and noted that it meets AISI Grade 1526. I don't know anything about this steel grade.
The client understands that we cannot increase the height without some reinforcement, and we intend to design this reinforcement if possible.
Can anyone explain what issues I will have working with the AISI 1526 instead of the API 5L pipe? Any suggestions on addressing these issues?





RE: Steel grades AISI 1526 vs API 5L-X42
The elongation is a problem because X42 requires 22%. Something is not right given such low e. And your chemistry could be not 1526, instead, a HSLA grade possibly.
RE: Steel grades AISI 1526 vs API 5L-X42
There could be several reasons for the reported low elongation values for this steel grade; the first being tensile coupon size and orientation or this tube material could have been supplied in a cold worked condition. Second, do you have reduction of area values reported for the tensile test coupons? By the way what do you claim as acceptable tensile and yield strength values? What specification did you compare to determine acceptable values???
RE: Steel grades AISI 1526 vs API 5L-X42
We don't have reduction of area numbers reported for these tests.
We did have a couple more mechanical tests on this same piece of pipe. They used bigger cross sections - about 0.75" x 0.4". Both tested better, but still not at the API 5L specs. The yields were around 59 ksi and the ultimate around 71 ksi. The elongations in 2" were 18.1% and 19.3% for the additional two tests.
Is this what you are looking for?
RE: Steel grades AISI 1526 vs API 5L-X42
As metengr suspected your strength numbers look like a cold worked pipe. Are your tensile tests in transverse direction or longitudinal? Are they done at room temperature? They should be in longitudinal direction and at room temperature. Are they seamless or welded? What is heat treatment? Where is tensile couple being taken? Without original MTR, it is tough.
RE: Steel grades AISI 1526 vs API 5L-X42
This material if it is 1526 would fall under ASTM A 529. Looks like it would be a Grade 55 - 50 Ksi minimum YS based on the second set of coupons. Minimum elongation by specification is 20% for this grade.
RE: Steel grades AISI 1526 vs API 5L-X42
The 1526 grade was determined by a lab analysis. If you would like, I could list all the chemical information they gave us.
Our client will cut coupons longitudinally from the pipe when they have them tested. I assume they are tested that way as well. The pipes are usually welded with a vertical seam, but I did not see this one.
I do not know why they used different width samples for the additional tests. Actually, I had not even noticed that until you asked what sized samples were taken.
RE: Steel grades AISI 1526 vs API 5L-X42
After thinking about this, you need to reject the pipe material because it does not meet your original specification requirement and, most important , you have no traceability for this material. I am not a believer of trying to establish new pedigree papers on unknown material because of issues related to past fabrication. For example; this material could have been seam welded despite not being able to visually observe a weld because welded pipe can be turned to size. Second, other than limited mechanical property testing, you have possible notch toughness concerns if this billboard is installed in a cold weather climate. In certain applications you can disposition material to work using rigorous engineering analysis. However, when it comes to rigging, lifting or structural applications where you have risk of personnel injury or damage to property, there is too much risk to take on.