Buttering of weld joints

[Subrata Das]

Dear Sir

Can anyone describe me what is “BUTTERING”  stands for in welding joint. If it is done before depositing the weld metal on job, is it necessary to remove the same by back chipping.  

[john rodrigues]

Mr. Das,
Buttering is a technique in which weld is applied to the surface in order to acheive desired properties or required dimensions.

For example in fit-up/butt joint, if distance between two butting members is excess, buttering is done on one member to reduce the gap.

Buttering is also done on surfaces to provide metallurgically compatible weld metal for subsequent completion of weld.

Regards.

John






On Sat, 12 Jun 2010 18:22:35 +0530 wrote

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John Rodrigues

[limesh M]

Dear Subrata ,

 

I am also clueless about this BUTTERING.One of the WPS with me clearly mentioned two buttering layers in between hot and filling.But the current,voltage and electrode is same what we used to execute hotpass !!! so I feel the depth of penetration will be equivalent to hot pass.Some of our seniors advice is required to clarify our doubt "WHAT IS MEANT BY BUTTERING ".

On Sat, Jun 12, 2010 at 12:57 PM, Subrata Das <sd...@pkgroup.org> wrote:

Dear Sir

Can anyone describe me what is “BUTTERING”  stands for in welding joint. If it is done before depositing the weld metal on job, is it necessary to remove the same by back chipping.  

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[Muhammed Ibrahim PK]

Hi,

 

Buttering can be done to avoid PWHT of weld jont in some critical condition. If we butter the joint of a P5A material with stainless steel consumable or inconel and PWHT will be carriedout seperately the components. Then it is not required the PWHT of the butt weld as the final weld is doing in stainless steel/inconel weld metal.

Thanks & Regards
Muhammed Ibrahim PK

[faisal hanif]

Well Das,            The buttering is actually the edition of material by welding on the faces of the joint to provide final shape or suitable transition to the joint. For example: when we have to get an opening on the vessel for the nozzle during fabrication of vessel, and the size of the opening is found bigger than the required size by mistake after cutting. then we have to do some weld build up on the face of the opening to get the required size, this weld build up is called Buttering. See the definitions in the ASME sec IX may it will help you. Regards, M. Faisal Hanif --- On Sat, 6/12/10, Subrata Das <sd...@pkgroup.org> wrote:

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[John Henning]

Definition of buttering from ASME Section IX, QW/QB-492 Definitions:

 

Buttering:  the addition of material, by welding, on one or both faces of a joint, prior to the preparation of the joint for final welding,  for the purpose of providing a suitable transition weld deposit for the subsequent completion of the joint.

 

Simply it is weld build up of (one or both) base metal(s) before beginning  to weld the joint itself.  This can be done in order to make up for poor joint preparation as indicated previously, but also is done to minimize the effect of PWHT on a sensitive material or eliminate subsequent PWHT.  For the latter cases a couple of examples may be in order:

1.       If you wanted to weld P91 pipe to a stainless steel pipe, ASME Code would require a PWHT of the P91 at nominally 1400F (760C).  This temperature would, however, “sensitize” the stainless steel (cause carbide precipitation along the grain boundaries).  One way to eliminate this problem is to butter (or overlay) the P91 with ERNiCr-3 (or similar weld material).   The thickness of the butter must be sufficient to avoid the weld heat affected zone from extending into the 91 during completion of the weld.  You would then PWHT the buttered P91.  The joint would be completed by welding the stainless steel pipe to the ERNiCr-3 butter with ERNiCr-3 material and no subsequent PWHT would be required.

2.       A steam turbine manufacturer I am familiar with used to butter 2 ¼ Cr – 1Mo casing materials with carbon steel at some nozzle connection sites where it was undesirable to have stubs.  The casing was heat treated prior to final machining.  In the field carbon steel nozzles/pipes were welded to the carbon steel butter with no subsequent PWHT.

ASME Section IX, QW-283, discusses and governs welding procedure qualification when buttering is to be performed.  While not complex there are some significant details that need to be paid attention to.  I would suggest that peruse this section of the Code and if enquire further if you have subsequent questions.

 

Hope this has helped.

 

John

[Engineer Mech]

Could any one says, wats the allowable/acceptable thickness for
buttering?
according to AWS D1.1? Where to refer in AWS D1.1

THANKS

[Kathalingam Babu]

Hi

Buttering thickness exactly not given in AWS D1.1

But still you consider the C2.6.3 section.

Regards,

K.Babu

THANKS

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