Some concern has been expressed regarding the connection of stainless steel material to regular carbon steel in the field. A common thought is that galvanic action between the two dissimilar metals will cause the "less noble" carbon steel to deteriorate rapidly and fail. While galvanic action does take place initially, the carbon steel rusts and polarizes rapidly, effectively inhibiting further deterioration. If stainless steel is welded directly to carbon steel, the carbon steel section should be at least two times the thickness of the stainless section. A connection, which may be used to eliminate welding two dissimilar metals, is shown below.

Since threaded couplings are usually heavy, no difficulty results when stainless and carbon steel threaded connections are employed together.

Pictured on right:

• Slip mild steel ring 'A', with machined surface up over end of stainless steel joint.
• Attach stainless steel ring 'D' to top of stainless steel joint with chamfer on bottom.
• Assemble mild steel rings 'A', 'B' and 'C'. 'B' is an open ring. Clamp 'B' around 'A' and 'C' making sure that 'A' and 'C' are snug against 'D'. Tack weld in place.
• Seam weld 'B'.
• Fillet weld 'B' to 'A' and 'C' respectively.