Welding CS to SS Materials

[H Cameron]

Hi friends,

Can any body help me about that if joining carbon steel to stainless steel material is acceptable as per code SECTION 8 and B31.3 or not?

If yes or no which part of the code can I find the evidence.

Thank you very much for your guide.

 

[KevinNZ]

We have welded SS to CS many times. You need a qualified WPS to do this.

 

[H Cameron]

Previously I heard connection between this two types of materials may cause corrosion And because of that we have to use some nonmetallic part between if needed. It wasn’t right?

 

[marty007]

We weld these materials together all the time, no problem.

 

[EdStainless]

Connecting dissimilar metals can result in galvanic corrosion issues, but you have join them somehow. You need to evaluate the risks.
This is common even in corrosion sensitive environments, however these welds need to to be protected.

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

Proper selection of filler metal is necessary for dissimilar metal welds in certain applications. Good engineering practice reduces the need for DMW's in service.

 

[moltenmetal]

I would avoid any dissimilar metal welds in a corrosive service where the less corrosion resistant material (carbon steel in this case) is already a marginal selection. If it is a noncorrosive service and the only corrosion you're worried about is external, it's not a big problem.

As far as the mechanical integrity of such welds, if the weld procedure and filler metal are selected properly and all the other requirements of ASME IX as well as any additional local requirements you may have, you are good to go..

 

[MJCronin]

Mechanical joints (i.e. flanged connection) should also be considered by the designer as a alternative.

It should also be noted that, at welded piping joints where CS joins SS there is a stress concentration whenever there is a thermal transient event.

The expansion coefficient for these materials is significantly different.

MJCronin
Sr. Process Engineer

 

[weldstan]

ASME VIII and B31.3 do not limit joining of dissimilar metals. It is done quite often based on engineering service requirements.

 

[H Cameron]

Thank you guys