Welding AISI 405

[PAN]

I found the welding history of a vessel (SA 387 Gr.12 Cl.2) with clad material (AISI 405).

This document shows welding electrode as follows :-
- AWS A5.4 E309 for root pass
- AWS A5.4 E308 for finish pass

In my understanding AWS A5.4 E430 is suitable for welding AISI 405. Should we use E430 instead of E308 during repair? Please comment.

 

[unclesyd]

I would not use E430. I would stay with the original welding procedure. 430 S/S can be susceptible to corrosion by some media unless annealed.

 

[stanweld]

As unclesyd states, stay away from E430. Clad restoration of 405, 409 & 410S clad carbon and low alloy steels has traditionally been done with E309 first layer and E308 subsequent layers.

 

[PAN]

Thank you unclesyd and stanweld.

Instead of annealing temperature, can we carry out PWHT at lower temperature to improve corrosion resistance?

 

[stanweld]

Clad restorations often need not be subject to PWHT. If PWHT is required per NBIC and the Inspector, a Code stress relieving PWHT is all that you may do. You may not anneal!!

 

[metengr]

PAN;
The NBIC references the original code of construction requirements, where possible. In this case because of the nature of repairs, you would require PWHT per UCS-56 in Section VIII if you touch the 1 Cr-1/2 Mo base material. As an alternative, I would refer you to the 2004 Edition of the NBIC, RD-1100, which allows local PWHT - we had approved this alternative PWHT method in 2003.

As an option to the above E309/308 filler metals, I would also consider an Inconel filler metal like Inco 182 or 82 for weld repairs between the ferritic stainless cladding and 1 Cr-1/2 Mo base plate. I believe the Ni-base filler metals would reduce susceptibility to harmful carbide migration along the weld fusion zone during local PWHT and potential cracking in service.

 

[stanweld]

While the Nickel base filler metals would normally be recommended if PWHT is required and/or operating temperatures are high due to the more favorable coefficient of expansion matchup and elimination of the carbide precipitation potential when using 309/308, they too may not provide effective corrosion resistance in the specific corrosion environment, especially if it is sulfidic.

The Owner/User of the vessel to be repaired should be consulted with regard to selection of the repair filler metals.