Adam R.

How much strength should I expect from a forge weld?

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Good Evening,

I just started practicing forge welds and so far have been successful.  At least in getting the metal to stick and actually be welded.  My concern is that while it was definitely welded, the weld didn't seem as strong as I expected.  I practiced with a faggot weld (i think this is the right team for this) and checked its strength by severing the bend, putting it into a vice and trying to separate it.  I wasn't able to do this by hand, but it didn't take much to get the weld apart with a hammer and chisel.  I expected more.  The metal where it was welded looked very clean; almost shiny.

The details of the weld:

I used 1/4"x1 A36 hot rolled, folded the steal over to make a tear drop shape (about 1"x1-1/2" of surface area for the weld)  20 mule team borax and a chile forge 2 burner at about 19 psi (20 is max recommended).

Should the weld be nearly as strong as the parent material?  Or is this a typical amount of strength for a forge weld with low carbon steel?  I expected more because I wouldn't trust what I experienced to hold on a pair of tongs using a drop tong method, so I am guessing i did something wrong or incomplete with my test weld.

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a proper forge weld is as strong as the parent metal because its fully fused

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Probably didn't soak the stock long enough to get the deep penetration of the weld. As others said it should be as strong as the parent steel. Could you see a line where the two were joined?

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A good forge weld is as strong as the weakest alloy in the join. For example two layers of 1060 and one 1018. The billet will have a yield strength very close to 1018.

Frosty The Lucky.

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1 hour ago, Steve Sells said:

a proper forge weld is as strong as the parent metal because its fully fused

This is what I was under the impression of as well.

 

1 hour ago, Irondragon Forge & Clay said:

Probably didn't soak the stock long enough to get the deep penetration of the weld. As others said it should be as strong as the parent steel. Could you see a line where the two were joined?

Yes, there was a visible line.  It is quite likely it didn't soak long enough.  I got the piece to the same color as the forge but didn't wait much after that.  So the surface may have been ready to weld but not internally.

At least I have an idea now what to improve on.  Thanks guys!

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Forging after a weld can help up it's strength.  Remember that battleship driveshafts used to be forge welded up out of different pieces of wrought iron way back when. Also anchor chains for major warships were forge welded from WI.

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Setup is important. When possible we do a scarf. The scarf is slightly rounded. Start in the middle and slag is forced out towards the sides, thus no slag inclusions. When doing pattern welds this can't be done. So start welding along the centerline and work your way to the edges.

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a forge weld will be as strong as the base material to a limited extent.  (based on how well it was executed, proper heat, clean, etc, etc and direction of force). 

sounds to me like you only had a tack weld or a flux stick.   sometimes you can actually get 2 pieces of metal stick together with flux only. Of course it falls apart as its not welded at all. 

There are steps taken with a scarf,  scarf design and direction at which the weld is done.    In other words just like modern arc welding the weld joint design can benefit from having proper execution. 

Certain metals are easier to weld than others.  A36 is not one of my favorites. More and more it seems to be displacing 1018 HR (hot rolled) So end up using it more and more.  Yes it welds and it's fine but it's more sensitive to temperature and over heating. 

Forge welding is one of those things where experience allows for a lot of actions that simply can't be done at a lower skill level. Anybody can forge weld and with guidance it can happen from the first time consistently.  It's a basic skill set. 



 

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Anvil; can you explain why it "can't" be done rather than it's not usually done? I have seen it done both by grinding and by forging the billet to make the   |)(|  .

I usually don't do it; especially when I am starting with BSB&PS; but I won't say it's impossible.

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17 hours ago, ThomasPowers said:

I usually don't 

My bad. I don't usually use words like "can't".

Better said, I've never done it that way. I did consider it once upon a time, but upsetting the centerline of 8 pieces 1/8"x1"x6" seemed to be a daunting task. 

Actually when thinking about it grinding  does add some interesting positives as well as negatives. The negative is material loss. considering the loss during forge welding, this would have to be accounted for.

However on welds after the first, grinding just may create interesting pattern development.

Goes to show,, never say never.  ;)

thanks for the heads up.

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17 hours ago, ThomasPowers said:

BSB&PS

I'm sure when I'm told what this stands for I will be feeling foolish and slapping my forehead but could someone please tell me it's meaning.

Pnut

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Mr. Moose,

Thank you for the definition of BSB & PS acronym. I also found it very specialized, obscure,  and unintelligible.

Live and learn.

It is useful and I shall to commit it to memory.

SLAG.

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Gets tedious to type it all out when it's been mentioned so many times before.  For just messing around I like to start with 20-25 layers of BSB&PS.  For me it's a free material with decent contrast and if you try the quench&break test on the PS and use the stuff that hardens you can get a decent carbon content too.  If you need to juice it up an old black diamond file with 1.2% C, yes 120 points C, can be added either as san mai or in the stack for welding and folding and welding and folding...

Now talking anvils; are y'all good with PW, HB, MH, A&H, etc?

As a typist---I'm better with a hammer;  my old boss got me a retro keyboard as he said my pounding on the keys wore them out too fast on the modern ones.

Slag; I have found that if you just tattoo the information on yourself, using a rusty nail dipped in kerosene, you are less likely to forget it in the future.

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I too am better with a hammer than typing either on my phone computer. Between blacksmith fingers and that nefarious invention called spell check, I always spend too much time with digital whiteout. I swear, I double and triple check what I've typed, post it, reread it even then. Then comes a reply and I scan my OP and wonder just who wrote that! 

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My daughter stopped by to see my new office---said she could tell which one it was from down the hall from just listening to my typing...

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