Qualify PQR Carbon Steel NACE and Non-NACE

[Thuhuongengineer]

Hi Friends,
Our project has one kind of materials is Carbon Steel-NACE. I know that this is a kind of Carbon Steel desgin with NACE standards. I checked in the ASME that it has no effect on PQR whether Carbon steel is NACE or not NACE. However, Client still insist that we must Re-qualify PQR. I have no knowledge about how to qualify PQR with NACE materials.

If there are any other special tests for PQR or not while I have checked in Spec ASME and did not see it mentioned to.

Do you have any experience about qualify PQR with Carbon Steel NACE material or any knowledge of NACE materials?. Can give me advice?

 

[SJones]

Consult ISO 15156-2/NACE MR0175 Part 2

Steve Jones
Corrosion Management Consultant

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

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

 

[stanweld]

Go to API 582 to find hardness testing requirements. Most Owners will accept a requalification coupon with hardness testing only; as your previous qualification satisfies the mechanical property requirements of ASME IX. You may need to increase preheating and interpass temperature to meet the hardness requirements. Depending on thickness to be welded, you may also need to limit the Carbon Equivalent of the purchased, production materials as well.

 

[wegm]

Thuhuongengineer ,
As SJones told, you shall go through ISO 15156-2/NACE MR0175 Part 2 so as to see if the existing PQR covers its requirements. The main issue as stanweld told is the hardness and I agree with his statement "You may need to increase preheating and interpass temperature to meet the hardness requirements" although I would like to add that in such a case you may need to control the cooling rate (please have a look at this link:

http://myothitsan.files.wordpress.com/2012/12/hardness-preheat.pdf)

as well as I would add that if you can not meet the hardness requirements you may verify the necessity of PWHT. Please have a look at this link that clarifies welding issues for welding under the scope of NACE MR0175:

http://www.weldinguide.com/gdanastasiadis/viewtopic.php?f=5&t=244

regards
wegm

 

[pradipgoswami]

Thuhuongengineer ,

What're the details about your existing PQR.Could you provide the details as follows:-

-Base Metal,
-What're the documentations abot the base metals,Mill certs
-Thickness
-Welding Process/ Consumable
-PWHT-Yes No
-Mechanical Tests done and results.
-Any Hardness Test done ,if so what're the results

What's the material to be welded now??

Appreciate your response.

Thanks

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario, Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[Thuhuongengineer]

Hi pradipgoswami

Existing PQR:
+ Base metal: SA106 GrB
+ Thickness: 8.74 mm
+ Welding process: GTAW
+ Consumable: ER70S-6
+ PWHT: No
+ Mechaical test: Tensile, Bend test, CVN, Macro, Hardness
+ Hardness test result (As picture)

Now material: ASTM A106 GrB + NACE MR00175

 

[pradipgoswami]

ASME Sec-IX,QW-200.2 (c) allows changes to the existing PQR as follows. Only the extracts from that clause is mentioned here.Refer the code for details:-

-Changes to the PQR are not permitted except as described here.Editorial corrections or addenda to the PQR are permitted. Additional information can be incorporated into a PQR at a later date provided the information is substantiated as having been part of the original qualification condition by lab record or similar data. All changes to a PQR require recertification (including date) by the manufacturer or contractor.

MR-0175 does not impose a strict paper work requirements for the materials to be used in sour service.As per clause A.2.1.2 Carbon steels are acceptable at 22 HRC maximum hardness provided they contain less than 1% mass fraction nickel, are not free-machining steels and are used in one of the following heat-treatment conditions:-
a) hot-rolled (carbon steels only)
b) annealed;
c) normalized
d) normalized and tempered

Do you have the MTR for SA 106 GrB material used in the original procedure qualification, conforming to any of the NACE requirements as stated above??
If so, you may try to get the orginal PQR recertified to NACE MR-0175 and ASME Sec-IX (the original qualification) as per the guidelines of QW-200.2(c) stated above.

Although MR-0175 was not a part of the orginal qualification requirements, this may be feasible at the discretion of the inspecting authority, provided all the requirements are in place. As all the results of the mechanical testing , including Hardness results (on the original PQR) are within NACE MR-0175 range it would be worth talking to the AI about this.

If the above proposal is not accepeted , weld a coupon on the same grade , preferably same thickness and same welding varibles and test for hardness.

Let me know how it helps.

Thanks


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario, Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299