Welding 316 Stainless to ASTM A335 P5

Date 04-12-2013 20:56

ewpatnode,
It would depend on a number if things. 1. Is it P5A or B or C per ASME B31. 3 or P5A or 15E (AKA P5B) per ASME B31.1.? These materials could require PWHT. Both those codes exempt you from PWHT based on material thickness. (Except P5B or P15E grade 91 which is mandatory PWHT) 2. Also PWHT of austenitic stainless steel is very problematic and would need a considerable amount of thought before performed. If you can tell us what P# it is and how thick the material is and what code of construction your piping was designed to we can give you some advice. To be clear, welding of A335 P? material to 316 stainless is possible but we would need some more info.

Thanks
Jim

By G.S.Crisi (****)

Date 04-12-2013 22:47

Jim,
ASTM A335 Gr P5 is 5% chrome, 0.5 % moly steel. When welded to another A 335 Gr P5 it needs PWHT. Back in my days of erector engineer I took part in the erection of an oil refinery (B31.3) where there were dozens of tons of piping made of that kind of steel.
In ew's case it'll be welded to 316 stainless steel, for which PWHT is not applicable. I assume (just assume, not 100% sure) that it won't need PWHT due to the presence of 316 ss.

Giovanni S. Crisi
Sao Paulo - Brazil

By Jim Hughes (***)

Date 04-13-2013 15:26

G.S.Crisi
I was not quite sure if the poster was talking about P5 or another grade. ( probably should have taken his post at face value like you did) For P5A both B31.3 and B31.1 give a PWHT exemption based on thickness of material. If it is P5 or P5c B31.3 does not give the exemption and PWHT would be mandatory. (see Table 331.1.1 and paragraph 331.2.3 of B31.3) If the material in question is P5 then I would recommend a transition piece between the austenitic material and the P5 material such as a piece of P5A or P4. Again, as mentioned in my post there is some unknowns here such as a design code or code of construction, material thickness. If known could bring some clarity.

Thanks
Jim

By ozniek

Date 04-13-2013 04:08

Hi

If the requirement for PWHT is a definite, then the usual way of approaching this is to apply a butter layer of Inconel filler on the Cr-Mo material and then applying the PWHT. Then weld the buttered surface to the stainless steel, again using Inconel, but no PWHT required this time round.

Regards
Ozniek

By weldktm Date 06-10-2013 10:39

you could have a look to these links:

http://www.weldinguide.com/viewtopic.php?f=2&t=10
http://www.weldinguide.com/viewtopic.php?f=5&t=58