Re: [MW:17737] Clarify copper inclusion & tungsten inclusion

[Ramin Kondori]

Dear Tishteo:

If present in base metal (or weld metal), Copper causes hot cracking because of its lower melting point and low solubility in Iron. I have seen this defect in a few steel castings which we repaired them. Those cracks were rather wide and straight.

I have also seen one case in austenitic stainless steel (Type 316) which is called copper contamination cracking or CCC. Liquid metal embrittlement is the mechanism responsible for CCC. You may find this defect in automotive industry where they use copper alloys as resistance welding electrodes. Copper transfers to weld metal or HAZ during electrode contact and causes cracking.

Tungsten has a higher melting point and will remain solid during heat cycles like welding or heat treatment so it s severity is much less than Copper (in steel).

Regards

Ramin Kondori

Sr. QA/QC Engineer

SINOPEC

r.ko...@petroyada.com
+98-2123592322
+98-9132150320

On Wed, May 22, 2013 at 2:03 PM, tishteo <ban...@gmail.com> wrote:

My friends,

Can anyone help me to clarify what is diffirent between copper inclusion & tungsten inclusion. Is copper  caused  of cracking & not permitted but Is Tungsten  permitted following code?

Which one welding process appear defect like this. thanks for your help.

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[Rajaram chandrasekaran]

dear friend
the fillerwire will have copper for good arc initiation  ,while welding it may incur into the weld pool and stay as metallic  inclusion .the copper has low melting temperature ,while solidifying of weld pool,this inclusion will form as a liquid layer called solidification crack which is a major issue on that welding .this will occur in GMAW

In TIG welding process the tungsten from the electrode may melt and drops into the weld pool it will create tungsten inclusion

[veera raghava kommisetti]

From code point of view

Div 1 - inclusion are treated as porosity

Div-2 Ti inclusion not permitted

[george....@gr.bureauveritas.com]

 
To be more more precise, Code is distinguishing between rounded and elongated indications.

So, both copper and tungsten inclusions are to be treated as either rounded or elongated indications.

In which chapter Div. 2 is not accepting at all tungsten inclusions? I would be happy to know...

Cooper inclusions could be more harmful than tungsten inclusions
 

best regards

Dr. Georgios Dilintas

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veera raghava kommisetti ---23/05/2013 07:29:24---From code point of view Div 1 - inclusion are treated as porosity

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[veera raghava kommisetti]

Correction to my earlier statement.

 

Div 1 - To be treated as rounded indication

Div 2 - Not addressed

Section I - Rounded indication

31.3 - Elongated indication

31.3 - Not addressed.

[Kasimir Paul A Graf Von der Recke]

are you referring to the copper on the outer layer of the filler metal. Could this potentially make the weld more ductile than the parent metal ? regards

[Kasimir Paul A Graf Von der Recke]

would this be seen on the surface or only during microscopic analysis ? regards