Welding Aluminum Bronze to Carbon Steel 2

[muld0020]

Does anyone have recommendations for filler material welding SB171 UNS61400 to SA516 Gr70? Would this alloy be a better (easier to CODE weld) than SB171 UNS63000? The next question is welding the UNS61400 (or UNS63000) to UNS70600 (90/10 CuNi), any filler recommendations?

Does anyone have any practical tips for making these welds?

This would be for an ASME Sec. VIII D1, tubesheet to shell weld. I have flexibility in my Copper alloy tubesheet, but it must be readily weldable to SA516 Gr70 and 90/10 CuNi. We will need to qualify this procedure so I would appreciate any help.

 

[metengr]

I would use UNS C63000 with SFA 5.7 ERCu-Al A2 to join to carbon steel as well as to join Cu-Ni.

 

[stanweld]

ERCuAl-2 is recommended for welding aluminum bronze and 90Cu/10Ni to carbon steel. ERNi-1 could also be used.

 

[muld0020]

Thanks for the helpful input. Are there any added benefits to welding the CS base metal to the Ni Al Bronze vs regular Al Bronze vs 70/30? I'm most concerned with quality and ease in welding.

However if all things are equal the price difference between the alloys is about $1/lb, but I can reduce my tubesheet thickness based on the higher allowable stresses. It's a balancing act, and I'm not very familiar with this dissimilar weld.

 

[stanweld]

Your chief concerns with dissimilar welds are dissimilar expansion and thermal cycling resulting in thermal fatigue failure and galvanic corrosion of the less noble material in the environment.