RE: [MW:31291] Low Temperature and LPG Service, is required NACE requirements ?

Dear Kiran,

 

It seems to me that referring to NACE-H2S sour service (MR-0175 / MR-0103) for low-temperature welding with materials SA-333 Gr.6 and SA-350 LF2, for LPG service is not relevant for the reason that the LPG stored has already been stripped of H2S-type impurities in the amine plant.

 

On the other hand, Kiran seems to me that you have a confusion: for low-temperature service the main variable that is measured is the toughness, that is, the ability of a material to absorb energy in the event of sudden shock and is evaluated by the transition ductile - brittle of the material in a Charpy impact test (ref. UG-84 ASME Section VIII- Div. 1). Therefore, it is not the hardness.

 

Reviewing API 582 "Welding Guidelines for the Chemical, Oil, and Gas Industries" there are no references to hardness as a parameter that measures the toughness of a weld at low temperature.

 

Talk to the customer, certain that the WPS / PQR presented is correct and that only weld toughness needs to be evaluated.

 

Regards,

 

Ramon Briceno – Metallurgical Engineer / Oil & Gas

www.linkedin.com/in/ramon-briceño-976265b5

 

Sent from Mail for Windows 10

 

From: K K
Sent: Thursday, August 6, 2020 2:58 AM
To: Materials & Welding
Subject: [MW:31286] Low Temperature and LPG Service, is required NACE requirements ?

 

Dear Experts,

 

Good Morning

 

I have a piping class with Low-Temperature Service. LPG Service.

 

WPS and PQR Details as below :

 

Material: ASTM A333 Gr.6 to ASTM 350 Gr.LF2.

 

Thickness - 12.7 mm, WPS Thickness Range - 6.35 mm to 18.00mm 

 

Process - GTAW+SMAW

 

AWS Class- ER80S-Ni 1 / E7018 H4 R , SFA No- A5.28 / 5.1,

 

Impacte test @ -48°C 

 

Hardness - 228 HV

 

According to my line class required  Low Temperature and LPG Service.

 

I understand that sour service required NACE requirements.

 

I have a doubt regarding the above service required NACE requirement, so how I can know that service required NACE or Not.

 

And according to API 582 ER80S-Ni 1 not recommended and also hardness value shall be 225 BHN, but I couldn't find the hardness in API 582? 

 

My client is not accepting  ER80S-Ni 1 / Hardness - 228 HV, he needs according to API 582.

 

Please I am looking at your feedback in details on my doubt.

 

Thanks in advance.

 

Regards 

 

Kiran

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