welding 15NiCuMoNb5 (1.6368) welding 15NiCuMoNb5 (1.6368) gornik99 (Mechanical) (OP) 28 Sep 10 02:29 Has anyone experience of weldingvalve with A217 C5 body to pipe 15NiCuMoNb5 (1.6368)I would appreciate any help in this matter. RE: welding 15NiCuMoNb5 (1.6368) metengr (Materials) 28 Sep 10 08:10 The 15NiCuMoNb5 is similar to a P-No 3 base material, low alloy steel. The A 217 C5 is a casting, under ASTM A 217 specification and contains 5% Cr-0.5% Mo. Since this is a dissimilar metal weld, I would use a 90xx B3 electrode composition for filler metal. Use the preheat requirement for C5 (being the higher alloy).For PWHT, since this is a dissimilar metal weld, I would butter the weld prep surface of the C5 material using 90xx B3 weld metal, PWHT the C5. Complete the final weld to the 15NiCuMoNb5 using 90xx B3 and PWHT following the PWHT requirements for this material. RE: welding 15NiCuMoNb5 (1.6368) kalmari (Mechanical) 28 Sep 10 11:19 About PWHT of German material 15NiCuMoNb5. There was at least earlier a recommendation by steel manufacturers to carry out the PWHT at not higher than about 30°C lower temperature as the tempering temperature of original material to avoid the dropping of strength values. Without knowing more about this case and Code requirements this might be good to take into account anyway.