WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
(OP)
HI GUYS
WE ARE HAVING SOME ISSUES WITH OUR 316/CF8M CASTINGS.
AFTER THE PICKLING AND PASSIVATING PROCESS HAS TAKEN PLACE,
THE AREAS WHERE THEY HAVE BEEN COSMETICALLY WELDED, THE WELD MARKS SHOW UP AS BLACK PATCHES AND ARE MORE PROMINENT THAN BEFORE THEY WERE
TREATED.
THIS PROBLEM AT THE MOMENT SEEMS TO BE ONLY WITH THE TIG WELDED PARTS.
ANY IDEAS GUYS
WE ARE HAVING SOME ISSUES WITH OUR 316/CF8M CASTINGS.
AFTER THE PICKLING AND PASSIVATING PROCESS HAS TAKEN PLACE,
THE AREAS WHERE THEY HAVE BEEN COSMETICALLY WELDED, THE WELD MARKS SHOW UP AS BLACK PATCHES AND ARE MORE PROMINENT THAN BEFORE THEY WERE
TREATED.
THIS PROBLEM AT THE MOMENT SEEMS TO BE ONLY WITH THE TIG WELDED PARTS.
ANY IDEAS GUYS





RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
so we weld up any defects to smooth up the surface area , which will be machined out by the customer.
but this issue is has only started a few months ago , no process changes have taken place during this period.
the welding rods have been analysed and are a very similar spec to the parts they are welded onto.
just having a real game to work out why this is happening
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
http://www.picklingandpassivation.com.au/SiteFiles...
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
In many cases it is because the pickle is actually etching the residual delta ferrite out of the weld filler, leaving this material slightly porous on the surface. The pitted texture looks dark, or traps oxide leaving it with a color.
If you were to lightly blast the area before pickle it would be much less noticeable.
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Plymouth Tube
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
My advice will be to minimize the occurrence of surface defect, rather than keep salvaging them which is time consuming and expensive.
You have received excellent advice about discoloration , some of which was a learning experience to me.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
you have given me alot to think about.
i will follow up with the way the castings are weld repaired, see how they look after pickling which is carried out offsite.
As for minimizing the occurrence of surface defects, that's another issue altogether, most castings need touching up a little.
the slag-off (koag)always makes its way into the moulds when casting.
we are currently looking at other types of ladles to help eliminate this problem and keep welding to a minimum.
Thankyou Guys
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
Is it mandatory to do the Passivation or pickling of SS welding ?
if yes is any codes & standard supports documents ?
RE: WELDING ISSUES WITH 316/CF8M PICKLING AND PASSIVATING
Even welds that look bright will have improved corrosion resistance after a pickle.
Of course if you really cared you would either be using over-alloyed filler or doing post-weld annealing.
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Plymouth Tube