ATS-34: Desperately needs help w/this.

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godogs57

Joined
Apr 16, 2004
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If anyone can help me with this problem I sure would appreciate it. I have been making knives for a pretty long while, but mostly with 440C. I have currently made about 75 or so knives with ATS-34 and love the blades, but have recently begun having problems with the finish of the blades when putting on the final polish. I am getting some serious pitting on some blades. I heat treat at 1920 for 25 minutes, temper 3X @ 450 and it leaves me with a Rc of 59.5. After H.T., I take it on down with 120 grit, 220, 400, 600 and then polish. It is only when I get to, oh, the 600 grit stage do I start seeing the pitting in the blade. Naturally, they do not buff out. This has got me sick, as these were my Christmas knives for customers. What might be going wrong??? This does not happen in each blade, just about one fourth of them in each batch.

I have noticed some interesting things when finishing the ATS 34 blades and wonder what is going on....#1) The steel rusts like crazy when I am grinding on down from 120-600. I will be grinding a batch of 12 blades or so, at the time and grind all at 120, then all at 220, etc...by the time I finish a particular grit with all 12 blades, they will all be covered in surface rust. Go to the next grit and it grinds off, naturally, but it will rust again before I get to that blade again with the next grit. This NEVER happened with 440C for me...makes me wonder what is going on here...#2) I have noticed that the ATS34 is much much harder to work than 440C....it is harder on belts and you dang sure better have all your scratches out before you go down to the next grit, as there is NO polishing it out later on....I could get away with that with 440C, not ATS34! Am I imagining things?

Any comments/suggestions are sincerely appreciated. I am just a hobby knifemaker, making a hundred or so knives a year. I am not a full time maker like most of you guys. Sure do appreciate any help you can offer.

Thanks,

Hank H.
 
1920 for 25 minutes I would not think cause loss of corrosion resistance. Is it possible your pyrometer is off? I presume you are protecting the steel from oxygen while austenitizing. The pitting problem beats me unless it is decarburizing and you just can not detect the tiny pits until the finish is fine enough. Could it be possible it is within the steel, I wonder. This may be answered by someone such as Mete and you may also try dropping your soak time a few minutes (for the corrosion problem).

Interesing post and I will try to follow it.

RL
 
Thanks Roger...I am suspecting some sort of decarburization, but honestly wonder if I got a bad batch of steel??? The rusting while grinding is making me wonder if I really got ATS34...or, possibly some ATS 34 that may have been slightly off on the "recipie". I got the steel from a well known and respected supplier...got me scratching my head on this.

Would I do better to try some Turco as opposed to foil??? This has been suggested. I suspect Turco is not too popular on this forum from what I gathered on earlier threads.

Take it easy.
 
Even with the worst HT it shouldn't rust like that. You might have something else. More and more bladesmiths are using plate quench for the stainless and air hardening steels. Stainless is best HTed using foil since at the higher temperatures oxidize rapidly.Yes ATS-34,S30V are tough to grind but they make very fine blades .......Roger , are you back with us , all settled in ??
 
Hank, it is most likely the steel itself as you received it. "Modern" ATS34 is notorious for having little pecker track pits in the steel, often deep inside the bars. Many years ago, people quit using 154CM because of this problem, and the ATS was clean. Somewhere along the way things changed. Nowadays it's a crapshoot with ATS. Makes me wonder if the same suppliers to us get steel from a variety of manufacturers from their distributors?..

If Kit sees this, his input would be nice, since he was around this steel years back, too.

If you want to use the same formulation without the pits/contaminants, try the Swedish equivalent RWL34. 154CM is supposedly clean nowadays, and the new CPM154CM is supposed to be excellent steel.

If it's just showing up on the ricasso, try taking a bit more off the outside of the bar before use. I found that helped a little bit......

BTW, if the rusting is occurring pre-HT and with the blade wet, then it's normal. I've left a wet ATS34 blade next to the grinder, changed belts, and returned to a blade covered in flash rust many times.
 
Thanks again for your comments. It is encouraging to see that, perhaps, I am not crazy for suspecting the steel then. I got some 1/4" thick ATS 34 awhile back for some Bowies and ended up grinding half of the damn thickness off getting the pits out of it (slightly exagerated!). Should have just bought 1/8" stuff to begin with! The rusting I am experiencing is AFTER h. t., while finish grinding. That is what initially caused me to go "wait a dang minute...". I mean, this is some kind of rust here...so far, no problems after buffing though. However, never this kind of problem w/440C.
mlovett and Fitzo: Am I not mistaken: ATS34 and 154CM are the same recipie, only ATS34 is Jap and 154CM is Red, White and Blue???? And where can I get the other steels mentioned? Who might have the best price? I am seriously considering changing steels again if there is a better one out there. I do like the ATS34 though, but am not prepared to spend half my time fixing up screw ups so to speak. I just don't want to go back to 440C. Comparitively speaking, it is butter soft compared to ATS34. Any suggestions on comparable steels to consider would be appreciated.

Take it easy.
 
Yes, Mete and thanks. BTW, if ever on 40 and 20 CW segments look for me at about the lower 27 KHz spot (KD8BZY). I chase a little DX for a break at times.

Roger
 
ATS34 was originally Japanese. I am not certain who all makes it "offshore" anymore. It's main use isn't knife blades so I've heard it justified as "the pitting doesn't matter to the main market."

While you won't get the "best price" by any means, I'd order my 154CM directly from Crucible. No questions about quality or source, then, and the price difference isn't staggering.

The rusting sort of concerns me, too. I've got unhandled ATS34 blades 20 years old hanging over the bench with nary a spec of rust.

What tempering temp did you use? Bear in mind, there is a loss of stain resistance if using the higher (900*-ish) range for tempering on these dual-tempering range steels.
 
This is the reason I quit using ATS-34.The pitting got terrible.I even tried it from different sources and still had the problem.I use 440-C instead of it now with no complaints.Dave
 
I read of your problem Hank and I sympathise, sorry I cannot help.

Reading all the posts here tho got me thinking.
Just as a matter of interest, I have 2 pieces of 1/4'' x 2" ATS 34 in my shop, bought about a year apart from the same supplier and a while ago I noticed that the finish on them is vastly different. Both the pieces have not yet been worked at all, they are still in the rough state.
The one has a very smoothe surface, sort of dark grey and looking at the sides, it has clearly been sheared from a larger sheet, you can see where the guillotine cut it.
The other piece has a very rough surface, as if it has been bead blasted pretty aggresively and the color is black. It has not been guillotined as the edges are slightly radiused and the bead blasted finish goes all the way round. It looks like it was rolled to the correct width. Just an observation, they are clearly from different mills. This may just enhance what some other guys have said.

As for ATS 34 being made by some unknown "offshore" source now, I shudder to think. The Japs. have always made pretty good steel, if somebody else is supplying it now then one just has to wonder. My company, wanting to save some money made the mistake of buying some milling cutters from Asia some time ago and even though they are HSS steel, and TiN coated, they cut like crap even when they were new and did not last nearly as well as the local, engineering grade cutters. They are lying somewhere in a corner now, we refuse to use them, nothing more infuriating than a crappy cutting tool.:mad:
There are clearly different quality standards around.
Sheesh, this is scary, ATS is my steel of choice too.
Hope someone can solve your problem tho, however it does seem to be rooted in the steel. Too bad.:mad:

Mike
 
I had the same pitting problem about 2 years ago and that is one of the reasons I switched to BG42. I should have done it sooner.

I know that doesnt help you with your current batch of knives but you might want to consider trying BG42 or even S30V.

Thnaks Michael
www.adammichaelknives.com
 
BTW, NO steels are totally immune from this phenomenon. (It just seems that in the case of ATS34, what was once one of the cleanest steels, is no more.) A friend had this occur on several blades of S30V. At least in his case, the domestically produced steel was replaced free of charge by the manufacturer, Crucible.
 
Don't use Turco.It would break down around 1650 and become corrosive.It is fine on simple carbon steel,but not to be used on stainless (I mistakenly made the suggestion to use Turco on stainless once).Make sure your foil is rolled and crimped tight,with a piece of brown paper wrapped around the blade (inside the foil).
 
I am confused about the Turco. While I haven't yet tried the can I have, I thought I remembered Ken McFall at K&G claims he uses it all the way up to ATS34 temps. I got it to try on plain steels. It just says "Turco" on the label, though, so I've never been able to track down exactly what the specs are since there's no data sheet. You have any further info, Stacy, you could share? I'd really appreciate getting a data sheet on this stuff.

PBC, on the other hand, certainly DOES get acidic up at 1650F. Eats some big old pits in 10xx. :(
 
I quit using ATS34 some time ago due to it's constant problems of pitting or its blotchy appearance. The rust sounds like flash rust that seems to come in mere minutes when grinding 200 grit and larger with lot's of water. If ATS34 rusts, it leaves nasty black pits that go deeper than you'd guess in no time at all.
I now use 154CM (it's a very similar formula to ATS34) more than anything and recently made a few from CPM154CM. I've also done some in RWL34 which absolutely rocks in terms of the cleanest finish I've come across. The CPM154CM is supposed to compete with RWL34 in finish (among other things). It's an improvement over 154CM (also from crucible) but I'd still have to give the nod to RWL34 for a liquid mercury look.
 
tmickley said:
I quit using ATS34 some time ago due to it's constant problems of pitting or its blotchy appearance. The rust sounds like flash rust that seems to come in mere minutes when grinding 200 grit and larger with lot's of water. If ATS34 rusts, it leaves nasty black pits that go deeper than you'd guess in no time at all.
I now use 154CM (it's a very similar formula to ATS34) more than anything and recently made a few from CPM154CM. I've also done some in RWL34 which absolutely rocks in terms of the cleanest finish I've come across. The CPM154CM is supposed to compete with RWL34 in finish (among other things). It's an improvement over 154CM (also from crucible) but I'd still have to give the nod to RWL34 for a liquid mercury look.
Click to expand...

Where is the RWL34 available, Tracy? I have been working off an old run of Hitachi ATS-34, which is almost gone. This batch has been very good to me, and I will be very sad to see it go. I have heard good things about the CPM154CM, but I want to try the RWL34. Oh, and since I made my plate-quencher, the Higgins shop has been filled with the white light of radiant joy and goodness. LOL, just kidding, hahah but I do love my air-hardening steels.
 
I've been using ATS34 for years. While grinding,it rusts immediately if left wet. If I'm not going to finish grinding and put the blade down for awhile, I spray it with WD40. Before grinding again I remove the WD40 using alcohol.

The rust happens fast when the blade is rough ground. More pits on the surface from using rough grit belts. As you move up to finer grits and have smaller pits in the steel left by the belt, then it takes longer to rust.

ATS34 will rust over time unless protected and dry. Following proper heat treat and finishing, the steel is rust resistant unless left wet or with acid, such as blood, on the surface.

Sound to me like you're using as rolled steel and not removing enough bark to get under the decarb surface. That's the reason I've always used ATS34 flat ground steel. The grinding removes the surface decarb and pits.

Any steel direct from the rolling mill has a decarburized surface and pits.

I suggest you pay a little more and buy flat ground stock. That may solve your problem.

Yes, I agree that 154CM and ATS34 have swapped places over the years in variations of cleanliness. I don't know which one is cleaner now.

I've switched over to CPMS30V and am very satisfied with it, even in the as rolled condition, since I grind the decarb off before making the blade.
 
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