Working annealed "super" steels

[Rsq]

In their annealed form, how much difference is there in these steels? Would 1095 vs s30v vs s90v vs cowry y or x be very different to work with before they take a HT?

 

[Danbo]

Before heat treat, you're not going to see much difference. As long as they're fully annealed.

 

[Frank Niro]

I have found a big difference , but then it might just be the pieces I received were not as annealed . Frank

 

[james terrio]

I can feel the difference between O1 and CPM-3V on the grinder for instance, but it's not so much as to make me dislike working with 3V. To a production line grinding 100 blades a day or whatever, it would make a big difference in time and costs.

You definitely want to get close to your final dimensions and finish pre-HT with the "super steels", though, especially any containing significant vanadium. They are a royal pain to finish post HT compared to O1 or 1084.

 

[peter r]

pre ht not much. post ht harder to finish s90v cleanly without overheating the steel. i use sharp new belts post ht and try to get the blades down to 400 pre ht with higher grade steels.

 

[Jason Magruder]

S90v will dull a new file real quick even annealed, 1095 won't.

I notice a slight difference between carbon steels and the high alloy steels on the grinder. After heat treat they are worlds apart.

 

[Tait]

I found I didn't like 440C or AEB-L because they were too gummy - yuck! 1084 and O1 were NOT gummy.

154CM was better, and S35VN isn't gummy at all but does grind slower than O-1.

If you PM me, I can send you couple of pieces of scrap to play with if you like.

 

[mgysgthath]

Tait.. gummy?

 

[tiguy7]

The Vanadium carbides in the S30-60-90V series have an 82 HRC (hardness Rockwell C). I don't think those carbides lose their hardness in the annealed state of the steel. The matrix loses hardness when the crystal structure of the Iron and Carbon is altered, but the non-Iron carbides don't lose hardness.

 

[Nathan the Machinist]

Even in the annealed state, something like D2 has relatively poor machinability compared to something like A2. I could probably tell the difference between the two just listening to the cut. I'm machining some P20 today (prehardened chromo) and it is a lot like annealed D2.

I was surprised how quickly CPM 154 wore out cutters. It cut okay, but cutter life was poor.

The carbides in the super steels will wear out cutters (or belts) quickly. The chromium content of certain steels may make them gummy and I think contributes to work hardening.

Things like A2, O1 and 1095 actually process pretty well.

 

[Tait]

Tait.. gummy?

Yes, gummy. Like soft stainless. Or copper, but not as bad.

When sanding, the lee edge builds up a huge burr. Then you sand a bit on the backside to cut the burr off, and its formed a small burr on the front again.

Gummy was the best word I could come up with - if you can think of a better one, I'd appreciate learning it, 'cause gummy IS a little vague.

 

[ERIK KNIVES]

I have finished 440C, CPM154, AEB-L, Elmax and M390. I find them all difficult to finish, but I don't know any better. I'm still experimenting with belt progressions pre and post, but M390 may be the toughest for me. At least I'm writing the stuff down now.

I keep thinking I will try some 01....., but alas, next up is N680.