RE: [MW:9718] 9643] Consumable for High strain Pipeline welding

You are welcome, Manpreet. 

 

It is widely believed that uphill progression provides greater arc heating of the base metal (as compared to downhill progression), thus reduces the likelihood of incomplete fusion.  This may or may not be true in a specific situation, depending on the skill of the welder.  Incomplete fusion is considered to be a greater danger to weld integrity in strain-based design than allowable stress design, due to its tendency to concentrate plastic strain, which may induce plastic collapse and possibly separation.

 

--Robert

 

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of manpreet
Sent: Tuesday, February 01, 2011 11:51 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:9671] 9643] Consumable for High strain Pipeline welding

 

Dear Robert,

Thanks for your time, also Can you throw some focus on "Why is it recommended with uphill progression"?

Regards
Manpreet Singh


On Tue, 01 Feb 2011 21:55:46 , "Robert" <fusiondood@gmail.com> wrote

 

Strain-based pipeline design assumes that the pipeline may experience significant plastic strain during installation or while in service.  In order to avoid localization of this plasticity within the weld deposit, which could result in plastic collapse, consumables are selected to achieve a so-called “overmatching” condition between the weld metal and the adjacent base metal.  This is intended to produce a more favorable distribution of plastic strain across the weld joint.

 

--Robert

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of manpreet
Sent: Tuesday, February 01, 2011 4:36 AM
To: materials-welding
Subject: [MW:9643] Consumable for High strain Pipeline welding

 

Dear All,

Can somebody define High strain Pipeline Welding and why does it require much higher strength consumable than the base metal strength? For welding API 5L X60, Root pass is welded with E9016G, also why does it require Uphill progression? please provide your valuable inputs.

Regards

Manpreet Singh