PQR Weld Hardness and Charpy Tests for CS Plates

[Angsi]

Code: ASME Section VIII Div I / Section IX
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Lets say plate is A516 G70. Is hardness testing normally requested for in the PQR even if it is a non-NACE service?

Assuming it is a non-NACE application, what advantage does controlled hardness give us?
Thanks.

 

[FIF99]

Hi,

Yes hardness measurements are normally requested for PQR.
Hardness measurements give you good info about the quality of the weld. Normally the base material, HAZ and the weld will be measured.
Excessive hardnesses could be the result of inappropiate welding by using incorrect parameters disqualifying the welds.
This has nothing to do with NACE (sour service), although NACE is specifying additional requirements for welding.

Regards.

 

[metengr]

No, from my experience hardness testing is not typically requested nor required for ASME boiler and pressure vessel applications regarding weld procedure qualification of P-No1 base materials because it is not listed as an essential welding variable. There is no advantage or use of information for measuring hardness of carbon steels if proper welding practices and handling of carbon steel base materials are followed.

The only time hardness testing would be requested is for temper bead procedure qualification or by an owner/user specification.

 

[weldtek]

Agree with metengr. We are though, seeing an increasing number of customer specifications asking for hardness tests on the PQR's. Many of the chemical plants and refineries look for weld hardness due to the service environment and typically specify 200 Bn as the upper limit, however , we recently got one that called for 190 Bn max. Most often if weld hardness is an issue post weld heat treatment is specified, and HAZ hardness should not be a problem.

 

[FIF99]

Hi,

OK, although its indeed not a code requirement (ASME) we are mainly dealing with engineering specifications from clients (end users) wherein hardness measurements are indeed required to be included into the PQR.

Therefore I have stated 'normally requested'.
So far, realising that this is not a justification for saying that this is always required, I only experienced the hardness measurements as an obligation.

Do you have the same experience? I'm mainly participating in projects for the european market.

Whats your opinion, from a practicle point of view, regarding the value of hardness results related to the quality of the welds?

Thanks and regards

 

[metengr]

FKE;
Let me phrase it this way, for the cost involved in obtaining hardness testing, it is not worth the benefit for use on P-No1 base materials.

 

[robsalv]

In my job, Integrity / Materials Engineer in a petro refinery, I like to see PQR's with hardness traverses as standard.

Even more so on P1 steel PQR's because some mobs can tend towards the cavalier in these general type welds.

Cheers

Rob

 

[TomEun]

Angsi, I think you have gotten very good answers from honorable guys. I only would like to summarize for your concern below;
1. The hardness values are normally required for PQR by company requirements (spec.) in order to prevent any crack (i.e. SCC, HE, etc.) during operation even though it is in non-sour service. For wet sour service (i.e. NACE MR 0103), please find Table 2.
2. Normally the hardness values required by company specifications for PQR of non-sour service are very similar with that of Table 2 in NACE MR 0103.
3. The hardness values may be based on the surface of HAZ (after PWHT when it applies).
4. If you apply the PWHT (but not required from ASME Section VIII, Div.1, UCS-56) to control the hardness values, you may use the mitigation of impact test requirement (temperature) in ASME Section VIII, Div.1, UCS-68(c).

Thomas Eun
Materials and Corrosion Engineer

 

[ledon]

I generally work to ASME, AWS and Military Marine services specifications. Very rarely have I been asked to provide hardness sampling for any of these specs except military. Then only for high yield and high tensile carbon steels. Under military marine requirements Charpy's are always required for HY materials.
Under ASME I have run across hardness requirements for un-fired vessels of materials with higher Mo content and special service vessels.