Filler Metal for Unknown Tool Steel?

I think welding with the amount of fill rod needed to fill that bevel is going to pull the machined sides of the part "up." The part will end up bowed away from the pin. I don't think this will happen with brazing, at least not to the same extent.
Robert
 
Hey y'all, heads up on an apparently super good deal over on ebay. 1-lb of 3/32" Hastelloy-W rods for $43.99

ebay

This is a great price for these rods! I picked up a pound for myself. Might be good to have some stored away for special cases.

As far as the piece being cast, I do not think it is. The way is grinds, files and looks up close seems to be plain mild steel. On the one unmachined face you can almost make out ancient mill scale. Also the piece measures about 0.495" in thickness which tells me they just started with a 1/2" flat bar and cleaned up one side. Just a guess though.

I probably won't try to fill the V groove completely. If it ends up a little concave that would be fine. I wanted good penetration, hence the deep/large groove. I'll have it clamped tight to a big aluminum heat sink for welding.
 
Just for fun put a straight edge on the pin side and see how flat the face is before and after welding.
Robert
 
Here's what I came up with...

I clamped the part on a big aluminum block with another copper plate butted right up on the underside of the pin. This plate just happened to have a big hole in it the straddled the pin nicely.

EM520200.JPG

To keep pressure upwards on the pin I used a small arced piece of copper plate. It acted like a leaf spring to hold the pin in place.

EM520201.JPG


For the actual welding I swapped the spring clamps for vice grip pliers. I hit it with a MAPP gas torch for a few minutes for a little pre heat then welded around the groove with a 3/32" Hastelloy-W rod. In hindsight I could've used a 1/16" rod probably and the weld would've been a little more concave.

After the weld was laid in I went back over it with a somewhat hotter weave to flatten it out.

EM520203.JPG


I came out pretty flat to slightly concave which is what I was hoping for.

EM520205.JPG


I tried to do a nice tapering out on the finish.

EM520206.JPG


After welding I hit it with a MAPP torch a little bit to help it cool more slowly. It doesn't seem to have warped at all but we'll see when it's unclamped. Fingers crossed!

Thanks for all the advice guys! I guess I won't know if this is a good repair until it's seen some service.
 
Nice job!!

I'm really getting to grips with TIG brazing. Finding it very useful
 
It looks great!
-brino
 
That looks really great. I'm sure that weld is very solid. Can you tell if you got any warp at all on the pin side?
Robert
 
It's kind of hard to show in a picture but there does not appear to be any warpage. Holding a 6" scale as pictured I cannot pass a 0.0015" shim underneath it. I also checked it across the other way, perpendicular and it seems flat.

EM520208.JPG
 
Well done!


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