+44 (0) 114 4000850   |   US toll-free 877-399-1010


NACE MR0175 2015 – New Technical Circular 1 for part 3 (corrosion resistant alloys)

On April 6th 2016 the first Technical Circular of ANSI / NACE MR0175 / ISO 15156 2015 was published, you can download a free copy of this technical circular via the ISO 15156 maintenance panel or through the NACE website.

Technical circulars are there to keep the document updated in between revisions of NACE MR0175/ISO 15156 (referred just as NACE MR0175 from here on). Between 2009 and 2015 there were 7 different technical circulars which complemented the 2009 revision. Technical circulars become integral part of the main document.

This new Technical Circular 1 makes changes to part 3 of NACE MR0175, these changes are mainly relevant to the downhole industry:

  • 17-4 PH: Table A.27 which sets the environmental limits for wellhead and christmas tree components, valves, chokes, packers and other subsurface equipment (excluding bodies and bonnets) now has a remark to let the user know that the safe use limits on chloride and temperature have not been defined. There is also a footnote that spells out restrictions on the use of this alloy.
  • Nickel alloy 945 / 945X: Table A.32 has been updated to show reviewed environmental limits for these alloys.
  • Titanium alloy R55400: Table A.41 now includes limits for this new alloy.

For information on Nickel alloy 945 /945X and Titanium R55400 you just have to google the UNS number and you will find information from the manufacturers as well as published papers presenting the qualification of these alloys.

UPDATE 2018-01-10: Two Technical Circulars have been issued. You can read more following the link below:



With a wealth of experience in the oil and gas industry, we provide independent materials and corrosion consultancy to help companies reduce risk, save money and apply best practice in their oil and gas businesses.

Find out more by getting in touch – you’ll get an answer from a qualified, experienced materials engineer every time.


USA toll-free


US: 877-399-1010 (toll free)
UK: +44(0)1144000850

66 Eldon St
S1 4GT
United Kingdom