Testing welding and steel

[TheoRockNazz]

I wanted to test my small forge for welding heat, and then test the resulting steel. This is simple 15n20 folded 400 times at the lowest possible temp to weld... so I thought. After heat treating and attempting to break (lock it in a vise and bend it) it came apart at the welds... I think. 

Looks like delamination to me; It may be that I am not hitting the minimal welding heat as I thought, what do you guys think? 

[mike-hr]

In knife class #203, Rich says nickel don't like to weld to nickel. How much nickel is in 15n20?

[Rich Hale]

You did not mention how you prepped between layers,,or did you fold and weld?,,,,Looks like poor welds between folded or stacked layers...And I do have to wonder why you would try and see how low of a temp you could weld at...Do you have meters to show actual temps?

[TheoRockNazz]

I do 99% of my forgewelding at the two or three burner in the city where the powerhammer is... which is also where I forgot my thermometer. I was curious to see if my single burner that I use for heat treating and typical forging would hit welding temps. I boraxed as usual, folded my layers, must have been too low heat. Oh wells, thank goodness for the other forges.

[Loneforge]

I tried to fold on my first few billets Theo and they all failed. A wise man (Rich Hale) told me that I would have better luck by cutting and restacking. I tack weld the ends together and once I knew the billet has at least stuck in a few places I grind these welds off to prevent uneven growth in the billet.....and I always get rid of the ends of the billets near the welds as they almost always have some weld flaws near the ends. I ensure all scale is gone before restacking my billets. I never even try a weld unless the flux is dancing around like crazy. I am using a single burner forge and have been having decent luck with my welds. Prep of the billet is key I think. If the billet surfaces are ground nice and clean and I get the flux on before scale can start I usually have good success. Like anything though, 100% success is not likely to occur! Get back on the horse and try again!

 

Cheers, Darren

[Geoff Keyes]

Nickel is a booger to weld to itself.  OTOH, I have built billets with a third of the billet made from 15n20 stacked together, so it is possible.  15n20 is about 2% nickel, so I don't think it's that big a deal.  I suspect that you just are not getting hot enough, and you may have some suspect welds at the ends of a billet.  Even with a 30 ton press, the ends of a billet are vulnerable to delam.

 

BTW, the one steel that I have never been able to get to weld to itself is 5160.  The chrome in it causes all kinds of issues.  It will weld to other simple steels without any difficulty.

 

Geoff

[jmccustomknives]

Try slipping some simple carbon steel in there.  Having layers of the same stuff will not have a very bold pattern and like everyone has said, alloy steel doesn't like to weld to its self.

[Robert Yates]

Nickel is a booger to weld to itself.  OTOH, I have built billets with a third of the billet made from 15n20 stacked together, so it is possible.  15n20 is about 2% nickel, so I don't think it's that big a deal.  I suspect that you just are not getting hot enough, and you may have some suspect welds at the ends of a billet.  Even with a 30 ton press, the ends of a billet are vulnerable to delam.

 

BTW, the one steel that I have never been able to get to weld to itself is 5160.  The chrome in it causes all kinds of issues.  It will weld to other simple steels without any difficulty.

 

Geoff

 

 Much like the billet I sent you Geoff it has to be Hot to work it properly . and here is something for you about 5160 to make it a bit easier to work with .

 

http://www.caffreyknives.net/

 

Go to the (Bladesmith articles) in the drop down tab

 

 

they are good articles by MS Ed Caffrey

 

 

 

I hope these help you and others .

Sam

[Rich Hale]

I stole that cut, clean and stack from a past member here. JPH....more info than that weee little morsel is in his book The Complete Bladesmith and even more in the two he did after that. We can expect the flow to continue in book four when he completes it.
And no I do not work for him or receive monetary compensation for this.... :)


Theo you did not mention if you removed all the scale as you folded. From that I can only guess that low heat may be part of the problem?

[TheoRockNazz]

My equipment was limited, so I folded by grinding the surface clean and cutting almost all the way through then folding over. I think you're right about the heat... I had never seen this before and wanted help confirming what it was. 

I am certain I can get that forge to full welding heat; part of the issue may be that the forge is too long (used for HT mostly), I should move my fire bricks around and make a square-er. 

Darren, you use a single burner, right? What's your setup like?

[Steve Sells]

While pure nickel wont weld to itself, the 2% found in 15N20 isnt enough to be a barrier to welding or carbon migration.  I pointed out in the knife chat that many alloys dont weld the same as simple steels. Same with the less than 1% chrome found in 5160 and L5.  Remember that I and others have forge welded stainless steels in the coal forge.  Keep practicing, dont blame the steel,  we just need to learn the new alloy. 
 
Nothing wrong with experimenting, but there are spec sheets showing the welding and forging ranges for the steels we buy, If we work out side of those ranges, we are asking for problems.