Dear Sirs,
first of all a stressed "Cheeeers" Darren! :-)
I have long considered before I started to write this post and there's a simple reason for.
Who else have "cut their teeth" more in Stainless Steel Welding and Welding-Metallurgy than Chuck, Jeff, Henry... . I personally do not know anybody having larger expertise in Stainless Steel Welding as the mentioned Gentlemen.
Thus once again it was a true pleasure to read their replies and nothing further should be necessary to say.
But please forgive me, meanwhile you know me :-) and thus please let me make a very short addition, since there are on the other hand two major reasons for that I would like to write:
1. I am currently listening to Johann Sebastian Bach's Concerto No. 6 in B Flat Major, and this inspires me...
2. There are some particular information I have regarding the topic which I would be glad to share with you
O.K.
Since reddoggoose has stated in his initial post (Quote):
"I don't have any detail on composition, geometry, or size, all I know is it is on a casting repair..."
I have remembered a welding application been performed in the 1980's and where a previous employer of mine had specifically developed and subsequently delivered the filler materials for. I would paraphrase it as an application going in the direction of being a - already mentioned by Jeff when he uses the term - "...depender...".
Although it has nothing to do with the finally mentioned 316 (cast-?) alloy and I personally have never preheated "common" Stainless Steels as a measure of distortion-reduction (surely founded on the reasons to be read above) before I have welded them, I would like to treat this special "Stainless Steel Cast" welding operation.
This welding operation was conducted in the Switzerland, in a company, at that time one of worldwide leading ones in the field of casting stainless steel power plant components etc.
The material to be welded at that time was a DIN standardized G-X 5 CrNi 13-4 (~ 0.05 % C / ~ 13% Chromium / ~ 4% Ni) cast material. It's been used for instance for casting a 91 ton "FRANCIS-Wheel", please see also the attached FRANCIS-Wheel_jpg. I hope to translate it correctly when I say it is thus an "Annealed" Martensitic Chromium Nickel Steel. In Germany we are using the technical term "Weichmartensitischer Stahl" what should express that the Austenite is being transformed into Martensite and subsequently achieving highest mechanical properties in particular increased toughness properties by being annealed.
Before I would like to continue in respect to weld-processing this material, please allow to let me briefly explain what kind of welding terminology we are using in Germany, particularly in coherence with "cast steel welding". I mean that this is important to have a better understanding of what I would like to describe.
Therefore one must know that here we are distinguishing between three different terms in order to find out what kind of welding conditions are to be expected.
These three technical terms are:
1. «Structural Welding»
In using this welding procedure we have conditions as already Chuck has excellently explained by saying (quote):
"...distortion should be considered before starting the job, and using appropriate welding processes and welding sequences to eliminate as much distortion as possible..."
This means, that in first order different subcomponents should be joined together to a larger structure. By having the chance to schedule the construction b e f o r e the welding process is being carried out, one has the chance to consider the most proper conditions for welding, testing, positioning, dimensioning, clamping,... . By doing so one has the chance as well to consider measures for reducing or preventing distortion, respectively.
2. «Fabrication Welding» ("Fertigungsschweißung" in German)
Fabrication Welding, in regard to steel cast manufacturing, can be seen as a fixed constituent of the manufacturing process itself. It is used for the correction of defects or inhomogeneities within the cast steel part or component, respectively. Background of this welding procedure is to secure similar mechanical-technological properties comparable to those ones of the base material. And now comes the crucial point in regard to preheating the parts for welding. It is standardized that the "...residual stresses after welding may not significantly deteriorate the later intended use of the steel cast component...".
3. «Repair Welding»
This welding procedure is being used for "repairing" or "reconditioning" components or parts having been damaged while they were used under daily routine processing conditions. Herein one must consider that different metallurgical or mechanical properties can occur, after the "Repair Welding" has been conducted.
Well, for the next accomplishments we can now use the term "Fabrication Welding" which has been used within the Swiss company I am speaking of. They have mainly used the Shielded Metal Arc Welding (SMAW) for the correction of cast process caused inhomogeneities. Due to the fact that those parts to be corrected by using the "Fabrication Welding" are large components, having great masses and weights, one has to consider that the "defect-area" which can be located anywhere within the cast part and to be corrected by welding can be seen as an unwanted perturbation and thus can cause stringent residual stresses in the surrounding area of the weld.
This again can - in worst case - subsequently cause cracks and thus a partial damage of the "Fabrication Welded" part.
Therefore one had fixed that time a particular procedure for "Fabrication Welding" the stainless martensitic cast steel "G-X 5 CrNi 13-4" under utilization of the Shielded Metal Arc Welding process.
This special procedure I would like to show by attaching the "Actuating_Variable.pdf".
Herein one can see, that there a preheating (> 100°C) of the Martensitic Stainless Material (cast steel) is being considered and required. The major difference in regard to what reddoggoose has mentioned (reduction of distortion) is, that this kind of preheating procedure could - from my point of view - be rather seen as a measure to avoiding delayed cracking under occurrence of stringent residual stress conditions in between the areas of welded defects and the surrounding large and very large cast steel component.
I personally can rather not imagine that stainless steel cast components having large and very large masses or weights and to be "Fabrication welded", are afflicted with the risk of a large distortion after welding, but rather are at risk to be damaged by cracking mechanisms due to their stringent stiffness and inability to compensate residual stresses induced by the welding process.
However, this is - to repeat myself - certainly a very special application and surely not transferable upon a common level with respect to a "Stainless Steel Generalization".
As Henry, Jeff and Chuck have mentioned there are certainly too many peculiar reasons in charge of that this "Generalization" will not be feasible.
So far my humble try of a contribution to this interesting topic...
Best Regards,
Stephan
Hi Stephan!
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