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Multibar - Wont weld!


Alveprins

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Alright, so I wanted to make a multibar Bowie - and I am having some problems welding.

The construction of the blade is 3 bars of twisted UHB20C, UHB15LM and 15N20 mixed with tool steel (old rasps).

The images below range from left to right:

Weld 001.jpg

Weld 002.jpg

Weld 003.jpg

The two bars that have clearly taken the weld (they took the weld right off the bat...) are 15 layers of the above steels, twisted 40 times.

The single bar (edge) is 60 layers of the same steel (from the same stack actually) twisted 60 times.

 

Now - for some reason the edge bar will-NOT-stick... I have forged this bastard at white hot - and yet it will not take.

First attempt - the two 15 layer bars sticks, the 3'rd one actually falls off. I straighten the bars up, let them cool - and grind their welding-flats nice and shiny.

Second attempt - I hammer and hammer and hammer the damn thing, both by hand and machine. No use. At one point - it LOOKS like it has taken, but as soon as I try to flatten the bar out - I realize it has in fact not.

I am at a total loss here guys... :(

Anyone have similar experience? I mean - same steel, no clank or impurities between the bars... ... jeez...

Edited by Alveprins
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I'd be guessing and would probably go back to basics. Check fire condition and adjust to reducing environment. I'd try and set the weld with very light hammer and then go for an immediate second welding heat before continuing. I would probably also get out a 'touch bar' ( 5 mm ms rod drawn to a very long taper) , flux it up and just check when this steel is becoming tacky.  High C, alloy steels often weld a scarily low temperatures, AISI O1 as an example. Elevated temps can sometimes be the issue.

Hopefully a member with more experience with these specific alloys will jump in and set us all straight.

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58 minutes ago, MacKINNON said:

1. Check fire condition and adjust to reducing environment.

2. I'd try and set the weld with very light hammer and then go for an immediate second welding heat before continuing.

3. I would probably also get out a 'touch bar' ( 5 mm ms rod drawn to a very long taper) , flux it up and just check when this steel is becoming tacky.

4. High C, alloy steels often weld a scarily low temperatures, AISI O1 as an example. Elevated temps can sometimes be the issue.

1. It is a propane gas forge. Temperature is above 1100 celcius.

2. I've done this. No luck. Light hammer - squeezing he bars together. It "looks" as they are welded. Then I go for a round two - with more force. Then I try to flatten and straighten the bar - and the bars just come apart.

3. I have never done this. I will try this for sure. Good idea. :)

4. I did not know this. Ordinarily I forge weld everything at "insane hot" - as I've always presumed that if it can weld - it will weld if only the temperature is high enough. The thing is though - I have forge welded these exact steels many times before - with no problems whatsoever. Also - the two bars that did weld - are the exact same steel, welded under the exact same conditions. .. weird.

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the first thing that I would looke at is the atmosphere of the forge , is it running oxidising?

 1100C is not hot enough  for forge welding. diferent people have thier own rules but I forge weld at 1300C Min. and as long as I am not burning the steel I run as hot as I can.

 Are you welding using flux? my indicator for flof the flux and that it is smoking when brought out of the fire.

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forging soul in to steel

 

owenbush.co.uk

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31 minutes ago, owen bush said:

1. the first thing that I would looke at is the atmosphere of the forge , is it running oxidising?

2. 1100C is not hot enough  for forge welding. diferent people have thier own rules but I forge weld at 1300C Min. and as long as I am not burning the steel I run as hot as I can.

3.  Are you welding using flux? my indicator for flof the flux and that it is smoking when brought out of the fire.

1. No oxidising inside the forge.

2. I wrote "above" 1100C.. The thing is - I have an infrared laser thermometer - and it maxxes out at 1050 centigrade - so I have no way of actually measuring the heat. Still though - my general rule is the same as you - "...I run as hot as I can..." ;) 

3. Yes, I am using flux. And it has been smoking when I bring it out of the fire - yes.

I have never made a single blade in my forge that has not been forge welded - so this is quite an unusual problem for me. I have never before experienced this. It is the very first time a weld has simply refused to take in this particular manner.

I guess I can make one more attempt - but after that I fear I will have smashed the whole bar to oblivion. Right now I am considering cutting off the bar that will not stick, grind off any residual steel from it, forge the bar nice and straight, clean it up on the belt sander - and forge a brand new bar for the edge steel. :unsure:

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I work mostly with my own steels , so there are problems that occur though C% and impurities etc. I'm similar to Mr. Bush, I like to weld in an extremely hot fire and I weld on a 'rising heat'. Since I work in the Japanese style the welding temp increases for the billet as the steel loses C% . The initial welds are often at relatively low temperatures ( hence the use of a touch rod if things are giving me issues).

Only one more thing I can suggest. Quench the billet out a few times. I only have a hypothesis about this but it seems to 'cure' some of my steels. If we're lucky a metallurgist will pop up and tell us the truth. Some of my high C% steels weld well at very low temperatures but after a few folds begin to become very 'unsticky'. If I continue they will progressively degenerate into a 'paste' , similar to burnt steel complex , FeS or high Phos. issues.  I can rule out the most obvious impurities ( I know what these look like, and analysis says otherwise), so I 'clutched straws' with "Critical Grain Growth". Martensite formation should 'reset' grain size and periodically quenching out my foundation billets did improve there welding/plastic characteristics.

Just a hypothesis based on limited understanding but it does work in my situation.

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9 minutes ago, MacKINNON said:

Only one more thing I can suggest. Quench the billet out a few times. I only have a hypothesis about this but it seems to 'cure' some of my steels. If we're lucky a metallurgist will pop up and tell us the truth. Some of my high C% steels weld well at very low temperatures but after a few folds begin to become very 'unsticky'. If I continue they will progressively degenerate into a 'paste' , similar to burnt steel complex , FeS or high Phos. issues.  I can rule out the most obvious impurities ( I know what these look like, and analysis says otherwise), so I 'clutched straws' with "Critical Grain Growth". Martensite formation should 'reset' grain size and periodically quenching out my foundation billets did improve there welding/plastic characteristics.

I can't say one way or another that this is a good, bad, or even real thing.  I COULD make up a fairly convincing argument for it to be true, but it may not be accurate (grain growth and grain boundary angles blah blah blah etc.).  I can say that you don't need to risk a quench to go all the way to martensite if it is accurate.  Just 3-4 (or more if you want) normalization cycles should reduce your grain enough.  Interesting theory.  

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You sound just like my metallurgist , Mr. Miller. When He told me I was an idiot and why wasn't I doing microscopy on samples. He also suggested a series of normalising cycles to which I said, 'Will quenching it out work ?'. With constenation on his face he replied , 'Probably , but it's a bit extreme and you risk severe cracking'. For me, at this stage of foundation forging the stuff is a mess anyway , so a few cracks just don't matter.

However, with the present situation in mind , normalising seems eminently more sensible ;-)

Edited by MacKINNON
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Given a situation where you are sucessfully welding and then It starts to not work you have to look at all of the variables and see what has changed...

 it is very easy to slip out of best practice without noticing when or why.

 

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forging soul in to steel

 

owenbush.co.uk

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On 11.4.2017 at 11:49 PM, MacKINNON said:

Only one more thing I can suggest. Quench the billet out a few times. I only have a hypothesis about this but it seems to 'cure' some of my steels.

At what temperature should I do this quench? Should I take it above critical - or just let it go dark red?

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I'm just refining steel so for me it's just a fast 'Trick'.

I would take Mr. Millers advice and try putting your billet through 3-4 normalising cycles. Check the data sheets for the normalising temps.

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I cannot guarantee that this will work, but it's worth a shot.

During your initial weld everything seems to stick, then it comes apart when you try to draw it.  So take it apart, clean the adjoining surfaces, flux and re-weld.  Let's assume it appears to weld together.  Next heat, reflux, let it soak at welding heat for 15-20 minutes... This will strengthen the bonds between the rods.  After 15-20 minutes, gently yet firmly hammer it together, treating it like it didn't weld the first time.  Reflux, and let it soak again.  Now see if it holds together when you draw it out.

I do not know the science behind it, but these long soaks have allowed me to save a few multiple bar billets despite the experts saying it can't be done.  Be sure to normalize the heck out of it afterwards to get the grains back down to a reasonable size.

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George Ezell, bladesmith

" How much useful knowledge is lost by the scattered forms in which it is ushered to the world! How many solitary students spend half their lives in making discoveries which had been perfected a century before their time, for want of a condensed exhibition of what is known."
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10 hours ago, GEzell said:

I do not know the science behind it, but these long soaks have allowed me to save a few multiple bar billets despite the experts saying it can't be done.  Be sure to normalize the heck out of it afterwards to get the grains back down to a reasonable size.

I would say the science is diffusion and grain growth (which is kind of like a diffusion process).  Normalizing after the long soaks probably help solidify the weld as well due to the grain refining across the weld interface.  

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I've had this issue before but only when my bars weren't 100% square or when I wasn't hitting them totally on point for welding and compressed one side more than the other.

 

If your bars are becoming rhombus shaped instead of staying square or are starting slightly off square that could be why they seem to weld and then turn right back around and don't stay together when you try to draw them out. 

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Is there any chance you're decarburizing the outer surface and raising the welding temperature without knowing it?

Also, Emiliano hits on a good point. I found that when I became really anal about squaring things off, the welds took much better.

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3 hours ago, Emiliano Carrillo said:

I've had this issue before but only when my bars weren't 100% square or when I wasn't hitting them totally on point for welding and compressed one side more than the other.

If your bars are becoming rhombus shaped instead of staying square or are starting slightly off square that could be why they seem to weld and then turn right back around and don't stay together when you try to draw them out. 

I think you are correct Mr. Carrillo. The bar in question was in fact not completely flat on it's contact surface with the rest of the billet. I suspect this is indeed the reason - because I've never had a problem like this before, and then again; my bars have always been pretty damn square. I figured it wouldn't matter all that much - but it would seem it does.

1 hour ago, Al Massey said:

Is there any chance you're decarburizing the outer surface and raising the welding temperature without knowing it?

Also, Emiliano hits on a good point. I found that when I became really anal about squaring things off, the welds took much better.

Good point about the decarb. I will keep this in mind for future billets. :)

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Last night I went down to the forge and just chiseled off the bar that did not stick. At this point the whole billet is too long and thin for me to do anything about - other than use it for some other purpose later on.

Right now I am working on making a brand new billet. A stack of railroad track steel, and those plates on which the railroad track rests on is now waiting for me to forge fold.

This time - I will not be cutting it into pieces, cleaning up, welding with arch-welder and then forge welding again. I will dunk it in water to get the scale off, and simply fold it onto itself. I haven't done this lately - and want to see if it is a quicker way of doing it... I really hate spending hours on end with the angle grinder and arch welder... :P

 

So, I will still make a Bowie - but a big one! Also - I will use the discarded bars from my failed billet for the guard... I am optimistic. ;)

Edited by Alveprins
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The bars must be square with parallel surfaces, if not they will weld, then pop apart when the side of the stack is struck.  This happens to me more than I'd like to admit, and the long soak method I described above, combined with a big dose of stubbornness, is the only fix I know of other than tearing it apart and squaring everything up.  

If the mating surfaces are not parallel, the stack will bow.  When you hit it on the flats, the welds will come apart every time... Unless you soak the heck out of it.

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George Ezell, bladesmith

" How much useful knowledge is lost by the scattered forms in which it is ushered to the world! How many solitary students spend half their lives in making discoveries which had been perfected a century before their time, for want of a condensed exhibition of what is known."
Buffon


view some of my work

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8 hours ago, GEzell said:

The bars must be square with parallel surfaces, if not they will weld, then pop apart when the side of the stack is struck.  This happens to me more than I'd like to admit, and the long soak method I described above, combined with a big dose of stubbornness, is the only fix I know of other than tearing it apart and squaring everything up.  

If the mating surfaces are not parallel, the stack will bow.  When you hit it on the flats, the welds will come apart every time... Unless you soak the heck out of it.

I will not make this mistake again! (at least not on purpose :P)

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Alright - so I thought I'd give a little update...

 

Now, I didn't really as much solve my problem, but still... I managed to forge out a couple of nice billets today. Some more forging and twisting tomorrow - and I will be ready to do the same operation at which I previously failed - hence this post. ;)

 

Anyhow, everyone loves pictures, so here's a pic of my two stacks for the knife.

Stacks 001.jpg

To the left we've got railroad track and railroad plates all forged out and stacked - and to the right we've got 15n20 and UHB20C. The railroad steel will go into the body of the knife, and the latter into the edge. Gonna fold these to 16 and 78 layers respectively.

 

Oh, and one more thing... When making huge (for me they are huge... :P ) stacks - I finally get to use the "Devil-Tongs" my sister made for me for winter solstice last year!

Devil Tongs.jpg

Can you see the little devil? ;)

Oh, btw... I forge welded these two billets with no flux... And I must say - I noticed no difference between using and not using flux....

Edited by Alveprins
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  • 4 weeks later...

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