Gents, I have inconveniences with a swing check valve, between the body and the hinger pin (plug bolt) we have a leakage (steam), to us is urgently avoid the leakage, for that reason I suggest perform a seal weld (fillet weld) between the body of te valve (SA 216 type WCB) and the plug bolt of the hinger pin (SA 470 type 410 - 13%Cr) using  E7018 and PWHT 600°C.

perhaps I'm wrong with the filler metal?

I appreciate your comments

Quibo,
The suggested electrodes for such a welding are E410-15, 16. Please have a look at this link that specifies the preheat and PWHT requirements as well (only in case that the construction code is ASME VIII-1 or ASME B31.3)
http://www.weldinguide.com/gdanastasiadis/viewtopic.php?f=25&t=438
Moreover please note that you shall also check the PWHT requirements regarding weld thickness
regards
apwec