Weld with a matching alloy, not Inconel 625. Rene 41 is an 18Cr, 11 Ni, 10 Mo, 3Ti, Balance Ni supper alloy. Inconel 625 is only a 1% max Co nickel alloy.
If matching alloy is not available then the nearest alloy richer in the essential chemistry (Ni, Co, Cr, Mo) should be used.
All weld beads should be slightly convex.
It is not necessary to use preheating.
Surfaces to be welded must be clean and free from oil, paint or crayon marking. The cleaned area should extend at least 2" beyond either side of a welded joint.
Gas-Tungsten Arc Welding: DC straight polarity (electrode negative) is recommended. Keep as short an arc length as possible and use care to keep the hot end of filler metal always within the protective atmosphere.
Shielded Metal-Arc Welding: Electrodes should be kept in dry storage and if moisture has been picked up the electrodes should be baked at 600 F for one hour to insure dryness. Current settings vary from 60 amps for thin material (0.062" thick) up to 140 amps for material of 1/2" and thicker. It is best to weave the electrode slightly as this alloy weld metal does not tend to spread. Cleaning of slag is done with a wire brush (hand or powered). Complete removal of all slag is very important before successive weld passes and also after final welding.
Gas Metal-Arc Welding: Reverse-polarity DC should be used and best results are obtained with the welding gun at 90 degrees to the joint. For Short-Circuiting-Transfer GMAW a typical voltage is 20- 23 with a current of 110-130 amps and a wire feed of 250-275 inches per minute.
For Spray-Transfer GMAW voltage of 26 to 33 and current in the range of 175-300 amps with wire feed rate of 200-350 inches per minute are typical.
Submerged-Arc Welding: Matching filler metal, the same as for GMAW, should be used. DC current with either reverse or straight polarity may be used.
Here is a link for the above given information, always source your data :)
http://www.suppliersonline.com/propertypages/rene41.asp
Here are various vendor names for welding wires that are a material match for Rene-41 super alloy. (AMS 5800)
HAYNES® R-41 alloy
Pyromet Alloy 41 (tm)
Udimet R-41 (tm)
TURBALOY® 41
If your going for MC-Grade wire, my personal prefrence is United States Welding corporation. They have proven themselves in our in house trials to provide the best quality (yes there can be a difference in vendors) in super alloy weldng wire (rod and spools)
http://www.usweldingcorp.com/tds/tds5800.htm
More Technical data
http://www.hightempmetals.com/techdata/hitempRene41data.php
Of the various super alloys used in aircraft engine components, Rene-41 is one of the easiest to work with from the fabrication/maintenance welding viewpoint (at least as precipitation hardenable alloys go.) GTAW operations are pretty standard, with the usual considerations for surface prep and argon backup.
Thanks to both of you!
Lawrence- If I use the R41 filler, I have heard from several sources there are extreme problems with hot cracking (and pwht cracking problems), and our only solution was to have the parts welded in a shop which can heat treat directly after welding. By the looks of your post, welding is similar to stainless procedures. Is this the case in your experience? Or is this material this heat treat sensitive?
I was hoping that I could utilize Inconel 625 as a filler because we stock it where I work. I noticed that Cobalt/Titanium was nil or almost in 625, but I was hoping:
1: the finished welds would have sufficient strength for the temperature they will endure, about 1400 deg F max.
2: would have enough ductility to avoid cracking, but still have greater stiffness at temperature than the SS316L we currently use for our jet vanes.
3: We could also possibly avoid a heat treatment step due to the ast welded ductility of the 625 material.
We would also definitely like to have a filler with better availability and lower cost than r41, but it is not a big issue. Mainly we are looking to get the jet vanes strong enough so that we do not bend them under load. As the 625 material is approx 10 times as strong at our working temp (vs 316L), it easily exceeds our needs. I just do not want to waste our pieces of R41 needlessly, as I have little idea what the finished weldments will do, and the R41 did cost us about a hundred bucks a pound- Ouch! So, basically I was just hoping to get an educated guess/opinion on whether it will work or not.
Thanks again!
-James
James,
I'm a bit spoiled and used to the stress relief equipment being on hand. Also, I'm used to a very structured atmosphere when it comes to filler metal selection. Filler metal changes without Engineering Varience Authority (EVA) is not a thing I would consider in aircraft componant fabrication or repair. No way could I guess about the combination you mention nor would I even attempt trials until I had hard copy paperwork approving the match.
The ASM Metals Handbook Vol. 6 has very good filler crossmatching charts. The wire vendors themselves are another route to take when looking to make a change. Next would be the standard practice manual of an aerospace giant. Pratt & Whitney is tops in my book.
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