I think you can use non-Nace carbon steel saddles providing they will be stress-relief heat-treated to ensure the hardness is less than 22HRC (Rockwell C hardness, equivalent to 248Hv or 237HB). NACE MR0103/ISO 17945, ‘Petroleum, petrochemical and natural gas industries Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments’, is intended for onshore process plant.

See the link bellow

luis

hope it helps


https://www.twi-global.com/technical-knowledge/job...

Essentially, it's fine provided that the attachment weld zone, including the HAZ on the saddle side, meets the hardness requirements of MR0103. The problem in saying that will be: ASME IX was probably used as the welding standard, thus no account of the variation in hardenability of the various grades and heats of material has been made. Looks like you will be out with a portable hardness tester taking quite a few readings. Enjoy.

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

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

Dear 0707 and SJones,

Understood. Is there any official interpretation or API/EN etc. standard saying that it's ok to do so provided hardness value is maintained below the limit stated in MR0103 (thru PWHT)? I am the project owner in a refinery hoping to salvage the project schedule by avoiding unnecessary rework.

Is it common that projects out there allow welding non-NACE saddles to NACE piping?

Thanks again for your feedback.

Dear Daniel_C,

Actually this is a grey area. However, you need to carry out PWHT to all the attachments. If this is too big a job, raise a 'deviation'.

Regards.

DHURJATI SEN
Kolkata, India

As you are the project owner of a refinery and it was a work mistake and you want to salvage the project schedule by avoiding unnecessary rework, if you try to fallow the rules of MR0103, you "almost" are, self supported. Otherwise as owner of the project, you have the power to decide yourself, to refuse the work and charge the constructor for the problems caused.

luis

"1.2.1 This standard applies to all components of equipment exposed to sour refinery environments (see Paragraph 1.3)
where failure by SSC would (1) compromise the integrity of the pressure-containment system, (2) prevent the basic function
of the equipment, and/or (3) prevent the equipment from being restored to an operating condition while continuing to contain
pressure.
1.2.2 It is the responsibility of the user to determine the operating conditions and to specify when this standard applies."

1.2.1
Are the saddles "exposed?"

1.2.2
This is the philosophy that will NOT get you any interpretation other than 'end user to decide.'

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

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

Dear all,

Thanks for the feedback. It is clear to me now that this is a shot I need to make.

Daniel