Yes the welding rod is kept in ovens to keep the moisture out of it. ASME
nuclear certifications require all low hydrogen rod (lo-hy) to be stored
this way. 7018 rod can be kept out of a heated container for a maximum of 4
hours, with 2 hours for 8018 and so on up to only 30 minutes for 110-18. I
believe that the military specification is pretty similar. The problem with
keeping rod out too long is that for it to be useful again, it has to go
through a re-baking process at a pretty high temperature. Our large rod
storage ovens at the shop are at a constant 250-350 degree temp, and any
lo-hy that has been subjected to cold temps for more than it's maximum is
thrown out since we have no facility for re-baking.
BTW Grant, you might have welded in some of our stuff...we made a lot of
HY-80 manways for Electric Boat over the years, probably with my name signed
off on the ultrasonic and X-ray reports. Hope you did a good job welding
'em in!!! :-)
All this is good food for thought for you guys that might be welding on your
oletruck in the cold months. Make sure the steel is warmed up and this will
help the structure of the weld as well as that hydrogen embrittlement
problem.
Wally / certified nuclear welding inspector, but only a so-so welder!
> I also used to do some welding on nuclear subs. I was under the
impression
> keeping weld wire in ovens was to preserve the coating or shielding
material on
> the rod.
> The only steel we used to preheat was HY-80 used on the pressure hull
and
> missile tubes. I was under the impression that the reasoning here was to
decrease
> the temp differential during welding. All high tensile and mild steel were
welded
> cold (and I mean cold here in Ct.)
>
> Grant
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
|