De-lam issue... picking brains

[Jason @ MacTalis Ironworks]

working on a 300 layer billet. I have a bit of a delamination problem, after the first weld at 25 layers, I found that I had a major missed weld at the core, and a couple minor partial welds. I flatfaced the 2 parts that fell apart, and will tack weld them back together for another attempt. I am pretty confident that the issue was caused by the fact that this is the first billet I have made that big without the aid of a gas forge and power hammer. I've always had good luck getting missed welds to work themselves out by cleaning, fluxing, and applying some smackage. Just wondering if anyone else has any tips on this. I am welding in a clean, but somewhat small coal forge, and found hitting temperature to be a little tough. I think I ended up getting it hot enough on the edges, but just didn't quite get there at the core. Any input on the matter would be appreciated. Also, I've often thought about attempting to clean inside the partial welds with vinegar just to see if it would break up any oxides that may have formed in there. Anyone ever try that?

[s meyer]

Hi everyones set up is a little defrent so what works for me may not work for you. 25 layers as a starting stack seems a bit high for a hand hammer.Maybee try starting with fewer in the stack. after the borax is dancing aroud and the billit looks good and stikey let it stay in the heat a little longer. I would make shure your stack is as clean as posible of scale before you stack it . Also longer time at tempeture to make shure the core reches the right temp .You might try starting your blows in the center and working your way to the edge.running a seriese of normalizing cycles between welds can help. I youse anihiedres borax for flux instead of twenty mule team and have better luck with it. Well I'm not shure of your prosess so sorry if I covered things you already do. Hope this helps.
Steve

[Jason @ MacTalis Ironworks]

Yeah, though the problem is more of getting heat in the core I think... after thinking on it overnite, I think I just might make it into 2 billets. layer counts on them are 14 and 11 where they didn't weld. I think if I tack a piece of mild to the are HC that is on the 14 layer, I can get a 15 layer out of it, which will be much easier to heat, as my firepot just doesn't seem big enough to handle a 25 layer stack. I don't mind hand hammering large billets, but I have always done it with propane which allows a much longer soak, coal requires alot of fussing around with the billet which makes it rough to get an even and thorough heat.

[Steve Sells]

while I am sure there are people that will disagree, I have found that tac welding around the edges wont allow the layers to shift as they start to weld, so it bubbles up rather than shifting and allowing the layers to stay parallel. tack ONE end only and start welding there, and move along as it welds.

Just my 2 cents worth

[Dodge]

I am welding in a clean, but somewhat small coal forge, and found hitting temperature to be a little tough. I think I ended up getting it hot enough on the edges, but just didn't quite get there at the core. Any input on the matter would be appreciated. Also, I've often thought about attempting to clean inside the partial welds with vinegar just to see if it would break up any oxides that may have formed in there. Anyone ever try that?

I agree with Steve. Weld one end and work from that end. Pushes impurities out as you work. Also I believe you may have solved part of the issue yourself. The entire billet needs to be at weld heat. Not just the edges

[Jason @ MacTalis Ironworks]

Dodge: I am definately no neophyte to pattern welding, I have easily a few hundred billets under my belt, but those were mostly all gas/powerhammer work done in a friend's shop when I was working for him forever ago. I used to run anywhere from 2-5 billets a day in those days. It was ultra rare for us to have delam issues, and any we did have, Gren usually fixed up. This is pretty definately an issue of a 25 layer billet being just too **** big to get to heat in my coal forge. As I said in my previous post, I am gonna just call it 2 billets and roll with that.

Steve: I just run tacks up either side in the middle, near the end, and on the handle end of my stacks. Once I have initial weld, and I've cut and stacked, I weld fluxless from there. I seal up the seams between the bars with a TiG torch or whatever I can get my hands on. Heat and weld from there. Works great.

[ThomasPowers]

For me a 25 layer billet is under 1 inch tall at first weld---S you must have short arms---or be using different stock!

How *wide* was the billet? Harder to get crud to leave the weld area if the stock is too wide for the amount of smackage you can employ.

My first billet was welded up around 1983 and I was teaching a couple of students a couple of weeks ago---one thing I emphasized was that the billet is sized for the forge! To start them off I had them do 1/2 length of my typical billet so they could have all of it in the hot spot at once.

I also taught them my fluxing trick: run the forge up HOT and stick the billet in and then turn off the air and go get a drink, pee, etc just to let the billet soak in a reducing fire. Then flux and start bringing the fire up slowly to go toward a weld. I figured this out as I was too anxious to start welding way back then and needed more time for the billet to be hot all the way through.