I am soliciting advice from those who have experience with O1/L6 damascus. I just ordered my L6 from crucible and plan on welding up a billet in a couple of weeks at a hammer-in in central Missouri. I've been reading and searching the threads but figured I would post here as well. Any advice on avoiding pitfalls different from than the 1080/15n20 I am used to. Are the welding temps about the same? I plan on using O1 on the outer layers. Any experience or advice anyone would care to pass on.?

Thanks!!

David Rice

Normalization is much more critical. A metallurgist would say that you cannot normalize this mix since it will just air harden, but that is if your goal is to soften the steel, the fact that it will air harden is the reason why it is so important. Never let this mix go from welding temp to room temp without some lower temperature cycles in between. It also doesn't like screaming hot. If you are used to white eyeball burning hot welds get used to something a little less instense (i.e. 2,200F instead of 2,400F).

If you are going to weld up a billet and then set it aside for later, set it in your gas forge when done and allow to cool slowly. It may just be superstition on my part but I get better success by folding it up and forging out a blade all in one shot. probably because of the natural stepping down of temperatures that occurs in forging a blade.

Weld it up and then allow it to cool to 750-800F then reheat it to 1500F then allow it to cool to 750-800F again then heat to 1450F or less and allow to cool. Speroidize anneal it or you won't be machining it at all.

I know my cycles in the last paragraph sound suspicious but the phases of the moon are not involved I promise;). The stepping down is to refine grain and disperse microconstituents so to lower the hardenability of a mix that is already very hardenable, and avoid it's blowing itself apart when dropping below 400F. You need to go to around 750F in order to obtain any sort of transformation, otherwise reheating to critical will not form new austenite grains, since you are still working with the same ones, hence no refinment of them. This stuff won't form pearlite on cooling so at 800F-750F you will begin to make upper bainite, don't believe me check it with a magnet, when the magnet sticks again you can reheat it and actually accomplish something. If you let it cool to 400F or less the martensite will be bad for it until you get that grain size down.

P.S. for hammer ins and demos I use Admirals L6 and 1080, it welds like a dream with none of the above issues. You know the first rule of demos- always go with the simplest and surest thing, because if it can go wrong...

Kevin- this great info for me as I am anticipating from going from 1084/15n20 billets to 01/L6 in the near future. I am choosing these steels as I am in the process of setting up salt HT equipment and would like to use austempering on my blades and if I am correct these steels are good steels for that type of HT. Would you be so kind to elaborate on speroidize annealling as i have had real problems with grain size and not being able to machine this stuff at all. From what you have said in the above thread I should consider normalizing the billet after each folding and welding sequence if the final fold/weld sequence is not be completed until later. I had intended to just normalize after the final weld and prior to finishing the blade before HT using the salt pots to control the temp stepping down 1500 to 1400 degrees in 50 degree increments. I guess my real question is to normalize this stuff in the forge after each weld (if need be) do you use a pyrometer in your forge to get an accurate temp read? Also to judge 2400 weld temp from 2200 without temp measuring insrument in the forge for me is very difficult. Do you recommend using a pyrometer in a forge?
sorry to ramble on here but the more I learn about this the more questions I have. I really appreciate the information you can provide and have provided in past posts on this and other forums. also when the next knifemakers get together in Mich?

Kevin, thanks as always for the great information. I made some detailed notes on the normalizing cycles. I had not realized O1/L6s propensity to air harden. Why is that? I thought they were both oil hardening tool steels. I will follow your advice on the cycles. I know you use O1/L6 quite a bit and read some other threads on swordforum, thats actually why I wanted to try it. O1/L6 seem to be very well suited for each other, so is there any greater risk of a billet delaminating other than the inherent problems of damascus. It's not like they are deep & shallow shallow hardening billet. I do see the logic in choosing steels that would both individually make good blades. Some opinionated guy on the forums has been advocating that.....
thanks

Dave Rice

Sorry for posting and running, but I had to do the Badger knife show over the weekend. There is one point that I must clarify about my suggestions. Weld away all you want and don't worry about it between welds, the only time this stuff will give you grief is if you allow it to go cold (as in hold it in your hands) from welding temperature. There is no reason to cycle between welds, it just needs to be done whe you are finished for the day.

I do plenty of normalizing at the end of forging but, simply normalizing this mix would leave a real challenge at the grinder, I anneal the forging and then grind off all the decarb and proceed to finishing the blade out. Before heat treat.

David, I have heated 1/2" L6 stock and threw it on the floor and then got a 61HRC off from it, while both it and O1 are designated oil hardening, they will both get pretty ornery just cooling in the air. In thin sections this is not such a problem, but in thicker sections it has always been a problem for me to cool from welding temp tp room temp.

Dating all the way back to McQuaid-Ehn and the work of Marcus Grossman it has been well shown what effect grain size can have on hardening, the larger the grains the deeper steel will harden. At very fine grain size these two steels will harden just fine in the slowest of oils, at welding temp the grains are much larger than anybody in thier right mind would want, so when allowed to cool the hardening will be very extreme. All of the cycling and normalizing I suggested is to correct the grain size before you reach the Ms (martensite start point). The cracks formed by this problem will not be like those formed in a 1095 tossed in water, instead it will be a large volume of lengthwise surface cracks that will ruin the piece. Although I recently had a very odd shaped cross section that did crack the blade in two from improper cooling after forging.

Thanks for the clarification. I had misunderstood a bit, got it now. I had to go back and re-read some sections on grain size and hardenability from my metallurgy material after reading your post but it makes sense now. I'm look forward to trying it at the hammer in. It's not a demo for me, just fun so no worries on the first time. I'm bringing my notes anyway. :)

i have had 01 harden in air in my shop before a frend wanted to try it out and he lost the blade

david; where and when is the hammer in , in Missouri. would love to attend. Thanks, stryder