[pickled]

I need to start this thread out with the preface that I have made a significant quantity of industrial and custom knives in my day, but it is currently NOT my primary business. While looking at a potential industrial project that required a delicate balance of mechanical properties, corrosion resistance and abrasion resistance I was drawn to 440C and AEB-L as potential prototyping materials. AEB-L seemed to have remarkable pricing at the stock thickness that I require! I have worked with numerous stainless steel materials in the past and have competency in contamination control, avoiding work hardening, thermal processing etc. This includes the standard austenitic varieties (303, 304 and 316.), martensitic 17/4 ph,as well as numerous powdered metallurgy "knife grades" (CPM 154, 20CV, S30V and 110V) used in boutique food and consumer goods industry production equipment. FYI- The current design that I am working with is pretty robust to tolerance mismatches, but the performance and corrosion resistance need to be spot on for the environment.

Having stated all of this I have ZERO hands-on experience with AEB-L nor do I have any feel for how it would machine, grind or take a polish relative to other materials that I have worked with in the past. The Sandvik 13c26 calls out some recommended feeds and speeds, but I'd like to ask if anyone with one of our class of machines has successfully ran this material and measured the resultant tolerances after heat treatment to 55+ Rockwell C. As I stated earlier it appears to be a cost effective option from a raw material perspective for now, BUT I typically try to envision things from a holistic perspective as to not lose any more of an already thin operating margin! Thanks, in advance, for any feedback that you have to offer!

[extdrive]

I do a fair amount of milling in AEB-L (custom knives as you might expect Cox Workshop) I'm not sure I'm understanding your question though. I heat treat to approximately 63 and then temper back to 60. What tolerances are you interested in? For the work I do tolerances aren't nearly as problematic as warping during heat treat.

[pickled]

Thanks for the reply and I really like the looks of your design. That AEB-L certainly takes a nice hand rubbed satin finish! Warping is certainly no fun to deal with. I'm typically running stress relief cycles with my stainless parts after any extensive milling ops so I hope that this stuff isn't any worse than the 17/4 ph that I have worked with.

My main questions have to deal with the machining quality that you get for fine features. Does it have a real tight sweet spot for not having burs in sharp corners as the parts come off the mill. A lot of my 300 series parts really suck for that from lot to lot of material! Speaking of which does it seem to machine consistent from lot to lot with your tooling (assuming you use carbide)? Does it hand polish up relatively easier than S30V for instance?

The last thing that I'm wondering about is whether the shrinkage on reamed holes is substantial. For instance when I'm working with other martensitic stainless I have to ream 3/8" holes 0.0005 oversized to get a good finish fit due to shrinkage. Trying to open this stuff up after it has been hardened typically is a nightmare so I was just curious if you have noticed pin fits to be a pain in the ass?

Thanks again for anything that you can answer. I certainly appreciate your time!

[extdrive]

I think you will find warping to be no bigger an issue than you have had in the past. I've found AEB-L warps less than some of the other stainless I've tried. I've started milling my primary bevels all the way down to 20 thou and that's when I've had to work more on watching out for warping during HT.

As far as the milling goes. I've recently switched to flood coolant. It likes flood coolant. Had a lot fewer issues with burs after the switch. It also really likes sharp tools (obviously right). Not as bad as titanium but same situation. When an endmill is too dull for titanium I can usually still get at least one knife blade out of AEB-L. It becomes very apparent when its time to switch an endmill out. And yes I only use carbide. It is MUCH easier to work with than S30V. That's good and bad I guess. As I'm sure you are aware (but for the sake of others that might be reading this thread) its not nearly as wear resistant as S30V. But it take an edge (and a sharper edge) very quick and easy. My experience is that the average person has a tough time sharpening a S30V blade, and field sharpening S30V is tough even for an experienced user...sorry I'm getting side tracked on the virtues of AEB-L

When I get my feeds and speeds dialed in and my fixture is ridged the finishes look fantastic. I buy all my AEB-L from the Steel Baron in NJ. Its does not appear to vary, very much from lot to lot. I've not found hardened spots, or at least if I have I've not noticed.

I ream all my holes 3/16 before HT. After HT I run some 400-600 grit sandpaper in them to remove any decarb or scale. After a quick sanding the 3/16 pins appear to fit that same as the did before HT.

I've tried to be accurate with my comments but take them all with a grain of salt as I'm still very much a novice when it comes to machining. Hope to have added at least some value though.

[extdrive]

Almost too embarrassed to post this but, I've got a video on my channel of a blade being machined. In case its of some help...

[pickled]

I think you will find warping to be no bigger an issue than you have had in the past. I've found AEB-L warps less than some of the other stainless I've tried. I've started milling my primary bevels all the way down to 20 thou and that's when I've had to work more on watching out for warping during HT.

As far as the milling goes. I've recently switched to flood coolant. It likes flood coolant. Had a lot fewer issues with burs after the switch. It also really likes sharp tools (obviously right). Not as bad as titanium but same situation. When an endmill is too dull for titanium I can usually still get at least one knife blade out of AEB-L. It becomes very apparent when its time to switch an endmill out. And yes I only use carbide. It is MUCH easier to work with than S30V. That's good and bad I guess. As I'm sure you are aware (but for the sake of others that might be reading this thread) its not nearly as wear resistant as S30V. But it take an edge (and a sharper edge) very quick and easy. My experience is that the average person has a tough time sharpening a S30V blade, and field sharpening S30V is tough even for an experienced user...sorry I'm getting side tracked on the virtues of AEB-L

When I get my feeds and speeds dialed in and my fixture is ridged the finishes look fantastic. I buy all my AEB-L from the Steel Baron in NJ. Its does not appear to vary, very much from lot to lot. I've not found hardened spots, or at least if I have I've not noticed.

I ream all my holes 3/16 before HT. After HT I run some 400-600 grit sandpaper in them to remove any decarb or scale. After a quick sanding the 3/16 pins appear to fit that same as the did before HT.

I've tried to be accurate with my comments but take them all with a grain of salt as I'm still very much a novice when it comes to machining. Hope to have added at least some value though.

Thanks! I'll have to look at the Steel Baron...have never shopped there before so will check it out. This was just the information that I needed to feel confident with bringing the material in house and using it for this non-knife application-THANKS! Though now you got me thinking that I might want to make a Nakiri out of AEB-L :-). I agree with you on S30V. Anything that I have made or own with S30V stock ends up with a convex edge because the belts and mist coolant don't mind the hard work required to finish it :-). Stropping with diamond paste and marble flour get me the last bit of the way on those blades. Having worked S30V on stones a few times I can also attest that it is a tedious experience to recondition a chipped bevel. As everyone says there is no perfect blade steel, but the utilitarian in me is thinking that maybe the left over AEB-L from this project will end up getting some slabs put on it and live the rest of its life in my kitchen. It sure doesn't cost as much as some of the other more exotic varieties and you CAN actually buy it.

[pickled]

Hey thanks for posting that video of your machining process. Wow I am amazed at the "friendly nature" of AEB-L based on what I saw. It is a pretty nice material to work with for its corrosion resistance and ability to thermal process to hardness based on your input and the literature that I have recently reviewed. I'm going to be using it for lighter load contact surfaces in wet environments on this specific project, but if it proves it's corrosion resistance in certain environments I'll probably try to migrate away from some 303 stainless parts to this material.

By the way have you made a table based fixture to make multiple blades yet? If not you definitely should. After getting ahold of some aluminum plate and CAD from McMaster you are only a few hours away as far as I can tell. At any rate I don't want to fill this thread up with talk of how to improve your process. I'll send you a PM and work forward from there. It's the least that I can do after you have shared so much to help me out.

[extrapilot]

Guys

Sorry to bring up an old thread-

Has anyone found any speeds/feeds data for AEB-L/13C26? I have contacted manufacturers/resellers, and they all seem to just be stunned that people would mill this material vs laser cut and grind… Don’t know why- it should be no worse than most of the better stainless tool steel alloys we use for blades these days- 20CV, 110V, S35VN, XHP, etc.

I haven’t had very much luck with solid carbide tooling in as-delivered/non-hardened AEB-L- tends to break cutters like nothing I have seen. I cut 6Al4V and XHP all day- no problems… So Im either really over on my SFM, or really out of whack on feed-per-tooth.

Thanks guys- really don’t know where else to turn when Sandvik and Uddeholm’s people sort of throw their arms up…

Best

[jwatte]

The short answer is: "No" :-)
But I, too, am interested in this.

Are you cutting with inserts or end mills?
Have you tried annealing the 13C26 before cutting? (unless it's guaranteed to be delivered in annealed state already?)
Do you use cooling? The steel may work harden.
Conventional or climb cutting? Conventional is better for surfaces that harden (or have scale.)
Also, have you talked to the Sanvik tooling makers, instead of the Sanvik knife steel sellers?

Have you tried any recipe that would cut 52100, or 316?

Finally, if the problem is breakage of carbide, have you tried cobalt steel tooling? You'd have to run it slower and it wouldn't stay sharp for as long, but it's tougher against breakage.

[extrapilot]

Tooling in question is solid carbide end mills- square and radiused. Same tooling we run on other stainless tool steels.

The material is annealed. We have an in-house Rockwell tester which helps to verify the condition, but the provider also has specified its condition.

We use flood coolant. We expect that it will work harden- so as with other materials of this class, we tend towards larger values on the IPT range for the cutter size.

We have been running climb on this- because we found less gouging on inside corners with smaller tooling (i.e. 3mm end mills doing stop-pin slots etc). And, we have not seen problems running climb on other stainless tool steels.

I have contacted multiple Sandvik sites- from the metallurgy crew to their tooling engineers. Everyone seems to point another direction. I think this is probably because the process people there deal primarily with the standard application- thin strip coils which are punched/laser cut and then ground on a high speed line.

I haven’t setup for 52100 or 316. I asked the metallurgy people at Sandvik and they suggested their best guess at a proxy would be 440a. But that hasn’t worked out. A vendor has suggested 42012/420HC as a better proxy, so that might be our next try.

We don’t run HSS in these materials. Maybe it is worth a try for AEB-L, but it just seems to be more a problem like with Ti- where you can destroy it with a good carbide end mill with proper feeds/speeds, but conversely it will destroy your cutter if you are out on SFM by 30-50%.

Just figured there has to be some guidance out there on what works with decent finish and tool life.

[jwatte]

If you solve it, please post back; I'd really appreciate it!