NACE MR0175/ISO 15156-3?

is there any certificate for NAB material ?? ANy limit to hardness value ??

Although many suppliers state "NACE MR0175" on their MTRs, this is not correct for the current edition. Alloys in section 3 of the document have limits on temperature, H2S partial pressure, pH, chloride concentration, and free-sulfur compatibility. Also different limits for many alloys used for different applications. It's not appropriate to simply state NACE compliance. There are limits for many alloys on hardness, heat treatments required, and processing.

For NAB, I'm assuming you are referring to nickel-aluminum bronze. Cu alloys do not have limits stated in NACE, just a warning that high general corrosion rates can be experienced. NAB suitability depends entirely on application and expected environment.

Thanks for your answers.. Yes I mean Nickel Aluminum Bronze...

So our vendor says , they can not give any NACE compliance/certificate for NAB material...

Should we accept it without any certification ? should we ask for any other tests ?

There is no certification for any CRAs, and no compliance requirements for NAB. Cracking due to H2S isn't the issue with NAB, general corrosion and cracking due to other species are issues with NAB. NACE MR0175 / ISO 15156 is only concerned with cracking mechanisms in the presence of H2S-containing fluids. I'd suggest taking a look in literature for the cracking vulnerabilities and corrosion rates of NAB in your particular fluid.

Thanks a lot for clarification..