Welding between SA335 P11 piping and 12Cr1MoV piping

[YANGzhou01]

We're encounting a Mat'l difference in welding:
The main steam outlet header of our CFB is specified as SA335 P11, but our client's piping Mat'l is 12Cr1MoV.
Can someone advise what kind of solution to this tough nut? either advice of WPS or any transition method is welcome.
Thanks.

 

[metengr]

I believe the 12Cr1MoV has the following composition;
0.05-0.15%C,
0.4-0.7%Mn,
0.90-1.2%Cr,
0.25-0.35%Mo,
0.15-0.30%V;

For joining these materials, the P11 to this low alloy steel, I would recommend an E9018 B3(SMAW)/ER90S-B3(GTAW) filler metals, and treat this as a P4-P5B WPS.