Nace MR0103 compliance

[Ram pokala]

Dear group members,

I am reviewing MTC for LTCS pipes and our PO specification was A671
CC65 CL22 sour service compliant to NACE MR0103 and plate shall be HIC
tested after simulation of final heat treatment of pipe.

Issue 1: As per MTC and reports plate material was Normalized and HIC
tested prior to rolling and welding. After rolling and welding as
pipe, PWHT was done as per spec(CL22). Can anybody clarify me what is
simulation of heat treatment? and is it required to carry out HIC test
for plate after PWHT of pipe?

Issue 2: Supplier does not declare in the MTC whether the pipes are
complying to NACE MR0103 or not. Is it mandatory for supplier to
declare in MTC? however supplier meeting the chemistry control and
hardness requirements.

Issue 3: When NACE MR0103 is specified in PO for the pipes is it
mandatory to carry out SSC test? or listed materials in NACE MR0103
can be used without SSC test/

thanks in advance for your reply.

regards
Ram

[pgoswami]

Hi Ram,

A671 CC 65 Cl22, is welded & stress relieved pipe , where the starting base metal is SA 516/65. ASME Sec-IX classifies this grade as PNo1 Gr 1. As per MR-0103, Cl 2.1.8, welds on these pipes needs to meet requirements of SP-0472 (i.e 200 HBW max hardness on weld deposits and 248HV10 hardness in HAZ).

Coming back to your queries, these would be the answers:-

Issue 1: As per MTC and reports plate material was Normalized and HIC tested prior to rolling and welding. After rolling and welding as pipe, PWHT was done as per spec(CL22). Can anybody clarify me what is simulation of heat treatment? and is it required to carry out HIC test for plate after PWHT of pipe?

 

• Simulation HT would mean subjecting the weld/HAZ to the HT cycle the production weld would undergo and ensure the required mechanical properties are in conformance to the design code. In this case  the  would be as per A/SA-671 and additionally hardness as per MR-0103/SP-0472. Please check if the supplementary requirements of A/SA-671 are applicable or not.

Issue 2: Supplier does not declare in the MTC whether the pipes are complying to NACE MR0103 or not. Is it mandatory for supplier to declare in MTC? however supplier meeting the chemistry control and hardness requirements.

--2.1.3 Carbon steels listed as P-No. 1 Group 1 or 2 materials in Section IX of the ASME BPVC, and used in one of the conditions listed in Paragraph 2.1.2(c), are acceptable without base-metal hardness controls

• MR -0103, allows Carbon steel to be accepted as stated above (for base metals, e.g plates),This does not apply for welded  pipes. Since MR-0103/SP-0472 calls for hardiness control , the manufacturer needs to declare that pipes meet /SA-671 % MR-0103 requirements.
  

 

Issue 3: When NACE MR0103 is specified in PO for the pipes is it mandatory to carry out SSC test? or listed materials in NACE MR0103 can be used without SSC test/

• SSC has not generally been a concern for carbon steels typically used for refinery pressure vessels and piping in wet H2S service because these steels have sufficiently low hardness levels. Improperly heat-treated materials, weld deposits, and heat-affected zones (HAZs) may contain regions of high hardness. MR-0103 allows design and construction with the materials which have demonstrated resistance to SSC. On that basis SSC test is not mandatory. However it is always advisable to carry out SSC test from good design angle.If specified the correct method of  SSC testing is important. Please read all the clauses under 1.4 in MR-0103.

• If the intended service is wet H2S service then NACE Document ,8X194:Materials and Fabrication Practices for New Pressure Vessels Used in Wet H2S Refinery Service may be cross referred. The correct SSC test

I hope the above illustrations  answers to all your queries.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-p...@sympatico.ca,
pgos...@quickclic.net

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