The NACE MR0175 requirements for shear rams

Question: The title of Paragraph A. in NACE MR0175/ISO 15156-2 is “Shear rams.” This section allows the use of rams made from quenched and tempered, Cr-Mo, low-alloy steels up to a maximum hardness of 26 HRC provided the composition and heat treatment are carefully controlled and supporting SSC testing is performed. The text of this section does not limit these provisions to just shear rams; however, the section title would imply that only shear rams are covered by its provisions. This apparent shear ram restriction was not in previous revisions of the standard. It is important to ram manufacturers as well as end users that all Cr-Mo, low-alloy steel rams, not just shear rams, be allowed up to 26 HRC to ensure maximum hang-off capacity and for anti-extrusion purposes. Do the provisions of A. apply only to shear rams or can they be applied to other types of rams as well?


The requirements for Cr-Mo, low-alloy steel rams in A. in NACE MR0175/ISO 15156-2 are not intended to be restricted to shear rams only, but may be applied to other types of rams as well. This is consistent with all previous revisions of MR0175.

This question is in relation to NACE MR0175/ISO 15156-2 Annex A.

Reference: ISO 15156 Maintenance Panel Inquiry #2004-16

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