question on NACE MR-0175 part2

[JBaxi]

Dear all

This question is regarding the NACE MR-0175 specification, part 2 for carbon and low alloy steels.

We have determined based on the level of partial pressure of H2S and in situ pH that we fall in SSC region 1, based on that we have to follow Annex A4 corrrect?

If we were to follow A4 then the hardness requirement are listed upto 300hv10 but based on section 7.3., the hardness requirements are 22HRC (iei 250HV10), so I am a bit confused what hardness requirements are to be followed for the parent pipe as well as the weld.

If anyone can help me on this. It would be greatly appreciated

Thanks

 

[SJones]

You need to read the wording more closely. Subclause A4.3 states "typically, fabrication and field weld hardness should not exceed 300 HV". Use of the words 'typically' and 'should' already alert you to the fact that the hardness quoted is not a requirement. You may then wish to review the warning shown above Clause 1, "It is the equipment user's responsibility to select the carbon and low alloy steels and cast irons suitable for the intended service."

So, do you feel lucky with a suggested 300 HV versus a required lower value from Table A.1 and Clause A.2?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[enmax]

22 HRC should be observed.

You might like to read this:

http://www.documentation.emersonpro...BusinessUnit=Fisher Controls Valves Division.

Regards

http://uk.linkedin.com/pub/terry-roberts/28/a9a/a10