Pipeline Welding Techniques

[thandion]

Good morning,

I am working with piping company which specialized on only aboveground pipeworks. And there is an upcoming pipeline work that we will possible get awarded.

Our old procedures are outdated, could anyone explain me current pipeline works. I mean is 2-3 group stick SMAW welding still popular?

Should we do Argon GTAW root and then SMAW fill? Work is roughly 100km, will full SMAW be faster? Or is it not worth it due to the better root result with GTAW root.

Thanks,

 

[21121956]

Hello everybody:

In my humble opinion, you should start by reading this textbook for beginners:

http://www.kobelco.co.jp/english/welding/events/files/2011ABC.pdf

By the way, in your company, what part of the work are you involved with?

El que no puede andar, se sienta.

 

[weldstan]

SMAW (7010/8010/9010) is still being used. SMAW + FCAW are being used. Automatic orbital GMAW is being used.

 

[thandion]

For X60 material, how about E6010 root then 7018 fill&cap.

Other than good penetration is there other pluses to use 6010?

 

[weldstan]

Why not weld it out with E7010-G assuming that you have access to competent, pipeline welders. I would recommend E7010 G for root and hot pass and FCAW fill for economy sake. E6010 would be recommended for the root pass for higher strength, microalloyed pipe to reduce the effects of dilution and thus mitigate hydrogen cracking of the root. Depending on ambient conditions, preheating would be recommended.

 

[gtaw]

Unless I am wrong, and it does happen more often than it should, the suffix "G" indicates the electrode doesn't meet a current AWS/ASME filler metal classification. The specifics are left to the manufacturer and the end user to define.

Best regards - Al

 

[thandion]

It should be 7010-G, not 7018. my bad.

 

[weldstan]

For example Lincoln's HYP is a E7010-G and is/was comonly used to weld X60 pipelines. If you need high toughness at low temps, other electrode filler metals would be used.

 

[jwhit]

I believe that in the case of a G suffix, it is the A No.(essential variable) that will govern usability and the need to qualify a procedure to use it, at least in the case of ASME IX. Hypothetically, the deposit chemistry may not fall into one of the A No.'s and would be qualified by listing deposit chemistry on the PQR/WPS in lieu of the A Number. Because it is a unique composition it should probably be listed regardless. As GTAW said, composition is whatever you and the manufacturer agree on to meet the required properties of the weld.

 

[wegm]

thandion,
It's true that GTAW gives good root but if you prefer higher productivity you can switch to GMAW-STT that is a type of GMAW process with which root can be effectively welded. Please have a look at this link: GMAW-STT (Surface Tension Transfer) for CS
regards,
wegm

 

[bernoullies123]

Sorry to high jack... but I was interested in the G prefix as noted by gtaw. So after a bit of digging I found the ASME/AWS meaning.

SFA-5.20 Part C states the following: The "G" indicates that the external shielding, polarity and impact properties are not specified.

 

[gtaw]

SFA 5.20 is for flux cored arc welding electrodes, not shielded metal arc welding electrodes. E6010, E6011, ...... E7018 SMAW covered electrodes are included in the SFA5.1 filler metal specification. One should look at the Annex for clarification about the meaning of the "G" suffix.

Best regards - Al