Piping Identification 1

[ChemEngr77]

I am a Chemical Engineer working in a hydrocarbons facility. How do we visually identify the difference between Carbon Steel (CS) and Low Temperature CArbon Steel (LTCS)? The piping has already been erected on-site.

 

[blacksmith37]

From the mill certificate specifications.

 

[fhadzafar]

Check the mill test certificate. Identify the alloying elements heavier than 21 atomic number. Do a little surface preparation on the structural members by grinding and prepare a clean surface. Perform PMI (Positive metal identification ) by portable XRF analyzer.
I've replied in context of steels under A203 ASTM specs which also fall in LTCS family.

 

[mrfailure]

You will not be able to visually differentiate between them unless material specification & grade are stenciled on the outside of the pipe. There are optimum chemistries for this but you will not be able to distinguish from run-of-the-mill carbon steel. The property that really differentiates is low temperature fracture toughness/Charpy impact energy, which you obviously cannot test nondestructively. This is why finding the certs has been suggested.

 

[weldstan]

By the specifications markings on the pipe placed on by the mill initially. You should also have had the pipe color coded. A-333 gr 6 is made to fine grain melting practice which involve the addition of small quantities of Al, Nb and/or V or combinations thereof. You will need to PMI analyze for all three elements.

Also examine the records from the pipe fab shop for the systems involved.

 

[Murdani A Sirajo]

Agree with Weldstan
you may verify using PMI to identified that on site. Than you analysis main alloying which you found by PMI.