Looking at the 1999 ed. : Section 10 states materials in Table 5 are acceptable, so L-80 (etc.) are acceptable as specified in 5CT. Table 5 should be referenced in Section 1(as it was formerly ); as now written it is unclear (I am no longer on T1-F1, or whatever the new committe name is.)
Some lack of clarity also comes from rewriting to humour the ISO people.
In the 2009 edition, in Table A.3 it shows L80 type 1 is acceptable for all temperatures.
Does that imply that L80 type 1 is accepted though hardness requirement differs slightly?
Ya it's similar for T95. API 5CT require Max hardness 25.4 HRC.
Let's make it simpler:
Now I have a casing/tubing material that complies to API 5CT L80, and its hardness is 22.5 HRC. Is it acceptable for all service temperatures based on NACE?
From the point of view of sulphide stress cracking only, yes for L80 Type 1.
Salmon2
I'm certainly no expert, it's simply a case of taking the time to read all of the specifications and their intertwined requirements. The principal issue is what hardness value is allowed for L80 Type 1 without having to perform laboratory testing. For a generic carbon or low alloy steel, the line drawn by ISO 15156-2 is 22 HRC. However, ISO 11960 allows L80 Type 1 to have a maximum hardness of 23 HRC. For T95, you will note that ISO 11960 automatically requires a sulphide stress cracking test; therefore, ISO 15156 will simply defer to the 25.4 HRC requirement of ISO 11960. Bear in mind that even though ISO 15156-2 allows 26 HRC, the manufacture will not be able to certify the material as compliant with ISO 11960 at this hardness level.
All of the above is based on ISO 11960 2004 with corrigendum and not the current 2011 version because I don't have it.