a problem about forge welding

[matthewfromers]

19 hours ago, pnut said:

There's a PDF you can download on the ABANA website called controlled hand forging that explains it. 

Pnut

Dear Pnut, I see the pdf and it's really interesting! Thanks for all the advice

16 hours ago, jlpservicesinc said:

In simple terms a scarf or the important part is the very end which needs to be as thin as possible with no square corner.

Dear Jlp, I've understand what a scarf should be!

so basicly this is what I've done, weld a piece of w1 on a bar of iron, without any scarf or preparation area, cut in alf and the "transition area" it's, of course still visible.

if I have correctly understood how kindly you have exposed me, in my specific case, what I should do is something like this:

this should prevent the formation of this "step" or "transition area". Am I right?

 

Thanks you ALL for the post and the knowledge that you 're sharing.

 

Matthew

[jlpservicesinc]

Matthew that is correct. 

[anvil]

Or make sure your two pieces are the same width. 

My process for this is:

!: forge weld along the width, as in your drawing above.

2: Forgeweld the edges as if you were champfering the edges. Meaning hold your hammer face at an angle and forge weld the edges,,, both sides so that the double champfer is centered on your parent stock. minimize the champfer width. The wider your champfer, the more you have to forgeweld and upset to get back to a rectangular cross section in step 3.

3: now, edge down and forge weld the "champfer" back into the parent stock. 

You should be able to do this in one heat, per section forgewelded. 

Take a second fw heat heat and clean it up.

[Frosty]

That's the type scarf you want for this type weld, there are others but this is what I use so I can't endorse others. 

Now to blow patterns. When doing this type weld you want your first blows in the center of the stack and progress to the edges. This pattern allows anything caught between the layers to be driven to the edges and out.  You don't want to spend a lot of time aiming or lay out a special pattern, just center the first couple few blows. 

There is also "soak time," this is the period of time necessary for necessary heat to penetrate to the center of the billet. This is true for welding and forging, if the center isn't hot enough the more plastic surface layers (lamina) will flow sideways in a shearing motion rather conducting deforming force into the center. 

Frosty The Lucky.

 

[anvil]

Frosty' way works as well. Just be very aware that by the time the center double mass is at a forgewelding heat, your thinner edges may burn, especially when using two different steels.

[matthewfromers]

20 hours ago, anvil said:

Or make sure your two pieces are the same width. 

Dear anvil, do you mean some thing like that in your forge process (in this case of course):

20 hours ago, Frosty said:

That's the type scarf you want for this type weld, there are others but this is what I use so I can't endorse others. 

Do you mean something like this Frosty?

20 hours ago, anvil said:

Frosty' way works as well. Just be very aware that by the time the center double mass is at a forgewelding heat, your thinner edges may burn, especially when using two different steels.

Yes I think that could be a risk! I'll try!

Thanks you all for the support!

[J.L.S]

that seems about right with what ive seen from my research on japanese tool smiths forge welding.
tho I have seen a video of a japanese smith with considerable skill, experience and beautiful hammer technique who did it like this:

1. 1 blow in the middle 
2. 1 blow on each corner
then followed by regular hammering working from the middle outwards
and he was incredibly fast and accurate, he knew exactly where he wanted his blows to go(least thats what it seemed like to me)

[Frosty]

That's the basic idea of the hammer pattern but don't get carried away, it's purpose is to allow inclusions a path to be driven out of the join. 

As Anvil says you can burn the thin scarfed edges before the center is soaked to welding temp. So, start heating in a lower fire until it approaches welding temp THEN turn the heat up gradually. 

I've also found a SPRINKLE of flux on thin stock prevents oxygen contact so it's much less likely to burn.

Another technique I favor is fluxing lightly when laying the billet materials before wiring or tack welding. Heating the billet to red or orange heat allows scale to form almost instantly on contact with ambient air. A dusting of flux in the joint before it's heated melts and coats the faces before it can reach temperatures that scale quickly.

Frosty The Lucky. 

[Ted Ewert]

I tried welding a couple of pieces of 3/8" square bar using the techniques suggested in this thread and both welds came out real good. I used both no scarf and a sloped scarf with equal success. I even drew out the scarfed piece with no separation. I then ground and polished the pieces along the welds and could only find a very tiny line where the welds were. A lot of places I couldn't find any line at all. I guess it's ideal to have no line, but these welds were solid nonetheless

Up to this point my forge welding had been spotty at best. Big thanks to everyone who has contributed their knowledge and techniques! I still have a lot of practicing to do, but I'm much more clear on the concept.

[jlpservicesinc]

Ideally flat to flat is also best for the best finish possible.  same width is the most important.  any iron/steel can be forge welded together at any point (end, middle, side, etc) and any shape (round, flat, hexagonal, etc, etc).  But the best welds or the easiest welds are with 2 bars ideally the same width.. 

thickness also plays in but for most or many, they will never experience welding 3/32" to 1"  or slipping in a 1/16" between to 1" diameter rounds. (these types of welds can have a shearing effect on the thinner metal). 

 Anyhow flat to flat the same width usually gives the easiest results and why welding at the end of a bar is usually used  as the first welds for practice. Also easiest to hold in the forge. 

Any other shape will make it difficult to get a really good seam unless there is enough forge work to completely change size/shape. 

When I am wanting hammer time but have no item in mind I will just start forge welding items together and use different scarfing techniques to do this. 

When I am making an item like in the videos on tapers I just cut the ends off and they go into a little bucket under the forge.  When I am looking for this hammer practice I pull out a bunch of these pieces and start to weld them all together and literally just use funky weld scarfs using the taper on any bar that will terminate in the middle or another bar. 

[matthewfromers]

Hello guys! And thanks for all your advice! I see that I've a lot of work about forge welding! On saturday I run my forge and japanese bellow with the purpose to make some other forge welding, after all you advice.

First of all I've choose more compatible material w1 with iron and 1070 with iron. The result this time are for shure better and I didn't have any delamination. I show my result:

I'm happy about that, I guess that I've learn a little something more! The "scarf fact" open up a world to me and I'm very happy about that!

In one of the forge weld I stumbled in some cracked small area, almost certainly caused by the excessive temperature, (the packet coming out of the forge threw out little stars), and I think that this problem depended precisely on this fact. Should I learn to recognize the temperature just below the melting temperature and weld to it, to avoid this?

Another question that intrigued me a lot was, how long can a package be for effective welding? It could be possible (using hammer and anvil) forge weld at 6 inches x 1.5 inches?
I'd like to get a material ready to be turned into a knife.

Thanks again to you all, have a nice day!

 

Matthew

[matthewfromers]

There's a little line between the two pieces of w1, I didn't find out anything about that on line, it looks like good forge welding and there's not any sign of delamination. It is normal?

[pnut]

Does the line catch your fingernail when you drag it across?

Pnut

 

[matthewfromers]

No, it doesn't!

[pnut]

If it doesn't catch your fingernail it's probably ok. I'd like to hear what others think though as I don't feel like I have enough experience to say one way or the other with much confidence.

Pnut

[billyO]

I've seen that before, and it's something that happens with forge welding at times.  Properly normalizing the steel usually takes care of it.  Another trick I've heard of to avoid this is to coat the pieces with graphite spray before welding together.  

[ThomasPowers]

How large a billet you can hand weld depends on how large a billet your forge can heat evenly to forgewelding temps and how fast you can work it on the andil.  I've als welded up billets that took more than one heat to weld the entire length; clean and flux and back in the fire and start inside the welded section and work towards the open end.

You may have a decarb line in that billet, speed and atmosphere control helps prevent them.

[matthewfromers]

very kind Thomas, I'm trying to figure out how to control the atmosphere of my coal forge (side turkeye, Japanese style) trying to keep the packets above the air inlet with a good quantity of pieces of coal on top to cover the all. Any other advice about it?

I really appreciate the support from you all.

Many thanks to all.
Matthew

[jlpservicesinc]

Matthew.  On a  solid fuel forge, there are 3 areas within the fire.  Carbonizing (reducing), neutral, Oxidizing. 


This Neutral would be the heart of the fire where there is a balance between how much air vs fuel is actually being burnt at the same time. 

Oxidizing is the lower part of the fire near the grate or Tue iron or outlet pipe.  and carbonizing (reducing) is above the heart of the fire. 

The way all areas in the fire are controlled is by how much air (both volume and pressure) is added.  A strong blast with much pressure will raise the neutral part (heart) of the fire and so on and so on.  (small fire, very low air blast, medium fire, medium blast and any combination there is)

So, much of where the neutral aspect of the fire is is controlled by the air. 

Some will say you need a deeper fire for welding ( deeper being with more fuel on top). With charcoal, this blanket helps to hold heat in and reflecting it back into the metal.  A clean fire. etc, etc.  There is a lot about it that is directly related to air blast and what you can do.


The reason why I mentioned it is the aspect of where the best part of the fire is.   Many think or have read more into it than need be.    Steel, forge welding etc, etc are all very archaic (imprecise) ways of working with metal. there is room for many errors and still, end up with a great product. 

there is always the "Ideal".  But this rarely ever takes place and puts a lot of stock into everything aligning or being perfect to get a great forge weld. 

You are on a very good start and as long as your not burning the steel and the metal is indeed sticking with no voids your way ahead of the skill. 
 

oh, one more note.  

if the metal is cleaned with no scale, fluxed and held tightly together and you raise it slowly to welding temperature the billet will almost weld itself as the temperatures are matched. 

the setting of the weld with the hammer is overdone as a cure for bad technique as there should be no gaps to begin with. 

Unlike other aspects where you are dealing with gaps,  larger to smaller sizes etc, etc,  (like making chain, or radical changes in shape or scarf). 

many times just a few light taps sets and completes the weld.  Its the reason why everyone mentions it being clean. 

When one moves away from flat welds and into other forge welded shapes  it really is amazing just how dirty a fire or how un perfect it all is to still bring about the desired results. 

[matthewfromers]

Dear Jlp,

I really appreciated your explanation is very clear and I will treasure it for the next times!
I'm trying to learn a lot what the forge "expresses" during the runs. The color of the flames, the type of sparks, the noises. In addition to being all very fascinating it is very important, in my opinion, to become familiar with the forge and bellows. The bellows, among other things, allow me a lot of air and flow control. Place some photos.

I feel very good about it and I think that this guy (fuigo Japanese), increases the feeling with the fire. It is very difficult for me to understand the color of the package when it is well covered with coal. I'm always afraid of overheating and I often try to control it.

Thanks again!

Matthew

[jlpservicesinc]

A Japanese type bellows is a very precise tool.  It allows full control of all aspects of air delivery. 

a Japanese style forge for blade work is by far also one of the better designs and it serves to conserve fuel and allow for the most options for blade making. 

All great choices.   If I were doing nothing but blade making,  These would be my choice for sure. 

what did you use for the seal on the piston?  does your fuigo come apart with traditional wood joinery?  Dovetails and pegs? 

there is a bunch of information out there that while it has some truth to it, is like a half truth.   Saying one can't do something or that something should be indeed perfect to get a certain result is not the case at all. Getting it as close to perfect will help give a better chance of success, but If something had to be 100% anything for it to be built or made or forge welded it would never happen as it would be a terrible failure every time. 

Not bragging nor trying to talk anyone out of anything. But I've welded in a fire that was 1/2 used up and filled with clinker on the bottom.  Is it ideal.. NO, not really but I also wasn't going to tear apart a fire to clean it just to tear it down again in 5minutes to call it a day to simply forge weld X, y, z. 

In the beginning of the learning curve there will be things that get thrown at you. but you are using a very clean fuel (charcoal), a good bellows system and with all things being even you have demonstrated by your samples that you grasp the main concepts. 

If you are into the testing of your welded steels there are different ways to test them to see how they will or won't fail. Bending,  knicking and bending,  cold forging, etc, etc,  These things are easy to do and they will all fail in some way. it can be fun though just the same. 

As pointed out before a good forge weld will not simply come apart.  

Looking forward to seeing some of your finished works. 

[matthewfromers]

Dear Jlp,
regarding the bellows, I chose to use all reclaimed woods that I already had and I was not very attentive to the traditional method of construction. I made something definitely solid but certainly not original. For the seal on the piston I used an old soft carpet that resembles a fur coat and keeps it greased with Vaseline! It works very well as a system!
I thank you for the suggestions and I will try to better test my results, for now, a small first experiment is this spear plane that I have finished and I must say, that there are no traces of delamination and cuts the hair of the arm very well!

[jlpservicesinc]

Looks great. Well done.   

[matthewfromers]

Thank you very much Jlp!

I made a little outline based on what you told me, to get a clearer idea of the concept, to see if I understood the above and why I like to do drawings

Can the areas I highlighted be considered consistent? Considering of course that they can change based on how much air is blown inside.

Thanks for your support, 

Matthew

[jlpservicesinc]

Yes they can be consistent if the air and fuel ratio remain consistent also. Which is ideal.

 

This means one can work in any given sized fire for the work loaded needed based on air pressure and volume. 

Small item , small fire, small air blast and still forge weld.

 

Medium item, medium sized fire, etc etc.

Large item, larger fire.