The billets for these knives started out being 17 pieces of 1/16 in thick 1095 and 15n20. They were drawn out and tripled twice to get the 153 layers.
I do all of my drawing at welding heat, I stop forging when the billet drops below 1200 deg F. I have seen bars come apart when forging at a low temp.
These billets were forged to 3/4 square before twisting. I also twist at welding temp. Before I twist, I forge the corners off of the 3/4 square billet. This removes the sharp edge and lowers the chances of cracks forming while twisting. You don't have to move alot of material, just enough to ease the corners. After the billet is twisted, I bring it back to weld temp, lightly flux with borax, and forge it back to square, well kinda like an octagon. It does not come out smooth, it still has the of the vallies from doing the twist.
Back up to crital on the temp and let her air cool (normalize). Then I clean her alittle with the belt grinder still leaving some of the evidence from twisting. Kinda looks like a steel candy cane at that point. If my initial billet of 17 layers was 12 inches long, my twisted billet of 153 layers is about 3/4 diam and 20 inches long.
A 6 inch piece of this twisted billet can easily be forged into a billet 1/8 thick 1.25 wide and 8 inches long. The knifes above are thicker than 1/8 and about 7.5 long. I forged the blade to help keep the stars in the bevel and save material.
I think you have the right idea about your temp being low. If you start to have delamination, you might be working the billet at too low of a temp, have cold shuts or slag inclusions in the billet, etc. Just start with clean material in the initial billet and work very hot if the material properties allow you too and everything should be ok.
By working very hot all the time you will get grain growth which is not desirable, The blades above were triple quenched during HT to try to reduce the grain size. I am going to try some thermal cycles soon to see what happens to the tuffness of my blades
Hope this helps.
