Is the hardness testing mandatory in NACE MR 0103?

[onrush]

Dear members,

When we apply NACE MR 0103 for pipe material,
is the hardness testing mandatory to prove the required maximum hardness value specified in NACE MR 0103?

Is it possible for pipe manufacturer to submit the
mill certificate that shows the hardness value under
the maximum one specified in NACE MR 0103?

Thank you in advance...

 

[gr2vessels]

onrush,
The NACE MR 0103 specifies that:
Clause 1.5.1 Hardness is related to tensile strength, a primary factor in SSC susceptibility. Because hardness testing is nondestructive and requires relatively minor
component/specimen preparation compared with tensile testing, it is commonly used by manufacturers in
production quality control and by users in field
inspection. As such, a maximum allowable hardness is
specified as a primary requirement for many of the
materials in this standard.
Also, the user must specify to the materials supplier (and the manufacturer) the extent of applicability of this standard. The manufacturer and the material supplier will obviously certify with suitable documents (tests, analysis, etc..), that the materials used and the fabrication processes are meeting the NACE MR 0103 hardness and other requirements. If in doubt, you can do your own hardness tests, but then again, what's the inspector's job if you have to double the checks?
As far as trusting the mill material certificates for your pipe, depends of where you buy the pipe from, USA or China. However, the material certificate should normally suffice for proof of hardness compliance with the NACE requirements.
cheers,
gr2vessels

 

[onrush]

Very thanks, gr2vessels

I agree with your opinion.

However the problem is that, for some cases, there is no hardness value shown in the material certificate.

For example, the hardness requirements specified in ASTM for carbon steel materials are as belows;

1. A105 (forging): mandatory
2. A234-WPB(wrought), A216-WCB (casting),
A672 (welded pipe): not mandatory (optional)
3. A515&516 (plate), A106 (seamless pipe): not mentioned

So, we should specify in purchase order that the hardness values must be indicated in mill certificates for the materials which does not require hardness test in ASTM.

Am I correct?

Thank you in advance.

 

[gr2vessels]

onrush,
Yes, you have to request the hardness values to be stated on the certificate. Many people simplify the issue as asking the supplier to provide the piping material in compliance with NACE MR 0103 and the supporting mill certificates. That will list the chemical composition, mechanical tests results, including hardness test results, etc...You can also add your own restrictions on composition or tighter hardness requirements, depending on your application.
cheers,
gr2vessels