Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

Hello Gents,

My customer is material compliance to NACE MR0175 / ISO 15156-3. I do have a specific H2S partial pressure, temperature, and operating pressure (environmental conditions). My question is how the actual material gets certified to the NACE / ISO spec.

If I determine that the material (UNS #)is acceptable for the environmental conditions based on the tables Annex A (table A.32), does that mean anytime I purchase that UNS # of material it is acceptable? Or does is the mill required to perform any type of destructive or non-destructive testing on each heat of material?

I am unsure if specific tests are required to demonstrate compliance on a lot by lot basis, or if the material is inherently compliant for a given environment based on Annex A.



RE: Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

For certification issues see:


The inclusion of N07718 in ISO 15156-3 is on the basis that, notionally, any material with the UNS number that has achieved the specified material requirements, and is deployed within the environmental limits, is deemed compliant. Whether that is "acceptable" is down to the call of the end user.

The material restriction for N07718 is, essentially, heat treatment condition and resultant hardness. Thus, the end user should satisfy themselves that the product that is put into H2S service has not exceeded the restrictions. Clearly, this necessitates some form of hardness verification, and the end user will have to specify, or agree to, an appropriate hardness verification programme that allows them to deem the material satisfactory.

You may wish to consult API Std 6ACRA.

Steve Jones
Corrosion Management Consultant


All answers are personal opinions only and are in no way connected with any employer.

RE: Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

The thing to watch with 718 is that the heat treatment required for MR0175 compliance is not either of the ones common for aerospace. So you need to specify the correct heat treatment.
Get the correct alloy and meet the property restrictions and you are good to go.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Inconel 718 compliance to NACE MR0175-3/ISO 15156-3 :2009

SJones & EdStainless,

Thank you for the reply. We are purchasing the material to API 6ACRA (PSL4). I do understand the difference w/ the heat treatments, and we purchase to the 120 KSI age hardened condition in order to meet the 40 HRC API requirement. I was unsure if I should expect additional test documentation, i.e. test results per Annex B. It appears we do not need any additional test documentation above and beyond the hardness check and heat treat charts.



Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close