First Successful Forge Weld

[Dan C]

I've tried to forge weld before, and the last time felt I was close but resorted to finishing it with my stick welder as I began having trouble getting the forge hot enough.  This seems to be an issue if it's been burning for more than 3 hrs and I haven't cleaned out the coke dust.  No problem getting hot in the first few hours though, it's an 11" brake drum forge using blacksmith coke and a squirrel cage blower, flanked w/ fire bricks.  This time instead of upsetting the end, splitting it and driving the bit into the end, I wanted to do faster that would ensure no lack of forging heat, so shaped a piece of Nicholson file into a U to fit around the end of an upset, squarred HC RR spike, I did do a small cheat by tacking it with my stick welder.  Maybe not necessary but I didn't want to complicate things by having it move on me, maybe next time I'll try wrapping it with wire, the stick welder was the easiest method for me.

 

 

Anyway after brushing, fluxing and saying my prayers to the forge welding gods, I piled on the coke since I'm not using coal to form a beehive with, kept checking the end of the spike and rotating it.  Seems like burning up metal before helped judge the correct temp because this time I pulled it out just before it turned into a sparkler, brushed and using one of my smaller hammers set the weld, flux'd again and returned it to heat.  The next time out I brushed again and used my usual forging hammer.  This time it appeared to be taking so then I was able to continue forming and upsetting the end.  I had to wrap things up as my wife had errands to run, but very pleased with what seems to be success.  I did notice a seam on the top that needs to be addressed.  I assume just repeat the above steps until no seams are visible, I did leave the piece buried in the forge to slowly cool to relieve stress.

 

From the top showing the seam.

 

 

Seen from the side which initially was squarred with the U shaped cap.

 

 

I've sell most of what I make, but this spike hawk's going to be the exception as this was a milestone and a goal I've had since beginning blacksmithing a little over a year ago. 

 

 

[Ridgewayforge]

If there is a seam, there is a good probability that some scale got in there, preventing the adhesion of the metal.

[Dan C]

I would think that as I continue to upset the end of the spike any seams would reveal themselves and I'd need to repeat the forge welding process until completely gone.  Sorta reminds me of what you do as a kid playing with playdough when mixing two pieces.

[Rich Hale]

That seam is a part of the weld that is not welded. Not a big deal for wot it is on and certainly a good outcome with a first weld. It is rather hard to weld that part of the joint for a couple of reasons: If you had tapered that way down before welding....It ir really hard to heat the thick part of the piece as well as the tapered part to the same temps. In both of your first pics you can see that the thicker end is hotter than the area where that bad spot is. Another reason is that a thin area loses heat extremely fast. By the time yiu pull from fire and move to the anvil you will lose heat that adds to the problem. 

A few thoughts that may help: Leave the end a little thicker. Before you even heat the piece, do a few dry runs, pull from forge,,have tongs in correct place so your do not have to turn or take any more time than needed. Have your hammer in hand so the face you need is right. This is not a race and if you see someone do it you may think it is done slowly...it should be a fluid motion...When I was learning I found that a flux from Cecil Swan helped me fix this very item. have not looked for it for along time..A flux mentioned on here several times..think it is called iron Mountain. It is said to weld at a lower temp than other fluxes. 

Back to the pics..the heated area needs to run up the bar toward the tongs a few inches. It stops at about the problem spot. .Maybe reduce air and let it soak a little longer...And a old time tip....After you have welded and wire brushed all scale from outside and it has cooled...hold with fingers up to your ear and tap it with a light piece of metal...it should ring..if not it is not welded solid. A mentor told me once that if every time I fire the forge I weld something,,it will get a lot easier. 

[Dan C]

It went easier yesterday, at least when I was doing the same task of welding a piece of file onto the upset end of a spike.  This time there were no seams, then I went back and fixed the seams on the other one.  Where it got interesting was when I forge welded a file along the length of a RR spike.  The first time I tried I burned up the small end (wasn't really surprised at that), 2nd time it worked without any problems. 

 

What happens to the grain size when you forge weld?  I would assume that it's enlarged and you need to then normalize a couple of times, perhaps bake in the oven for 400' for an hour to relieve forging stress.

[Rich Hale]

All covered in the heat treat stickies! :)

[Dan C]

Thanks, not sure if I'm looking in the right place, but I did find this thread which you had answered the question there! 

[Dan C]

It's taken me awhile to finish the knife and hawks I was making in this thread, but am finally doing so.  Reading other threads and this one about hamon lines, it seems that I would be able to have one appear since the cutting edge is an old file forge welded into an HC railroad spike and the line is caused by the difference in hardness between the two steels right?  Anyway I'll give this a shot and post pictures when I get them finished.

 

[ThomasPowers]

NO the line between different alloys is NOT a hamon.  A hamon is a line reflecting different hardening in a single alloy due to differential hardening.

[Dan C]

Hi Thomas.  I was thinking a line would show because the steel from the spike and the file are going to be a different hardness.  Not so?

[Rich Hale]

The line you describe is due to two different steels.

[Francis Trez Cole]

Dan I was reading through you first post and I though of a few things that might help you in your welding. first when you are prepering the piece to be welded on thin the edge that will give you a scarf and give you a cleaner weld the line in you second picture is from forcing a square edge into the parent stock. Second when you pull the piece of metal out of the fire do not waste time and heat wire brushing hit the 2 pieces together not to hard but enough to push out the flux and garbage. wire brush and then flux again reheat and weld hitting harder. Third I have found as you are pulling the piece of metal out of the fire the first time if you give it a little flick of the wrist most of the excess flux will fall off so on your first strike you will not have a big spray of flux going every ware. Hope this helps