hakr5,

Are you referring to any specific NACE code?

Specifically speaking about MR-0175:

Many factories now produce materials compliant to MR-0175. Without witnessing the actual tests as described in the code, you have rely on the manufacturer's certificates to determine whether the tests have been conducted on the material and whether the subsequent results indicate compliance.

Chemical composition alone cannot act as indicator of NACE compliance. To illustrate my point, compare chemical composition for API 5L X52 with SA333 Gr 6.

Additionally, for the same grade API 5L X42, one factory may produce non NACE compliant line pipe by running only tensile, bend and other tests as specified in API Spec 5L, while another fulfills the NACE requirements by carrying out additional tests as specified by MR-0175.

Furthermore, NACE compliance for, say, a piping system is a combination of several factors:
(1) Compliance of materials of construction;
(2) Welding procedure;
(3) Weldment and HAZ testing;
(4) PWHT, whenever required;

Unless you are required to specify materials for a job, I suggest that you look at the operator's or client's piping specs. Otherwise, speculating on the basis of Mn content may be a costly and time consuming exercise.

Regards,
NH Liew