1095 cracking?

[Ray Rogers]

Should already be annealed, soft as butter most likely ....

[metal99]

Very soft Ray. I just thought maybe from being cold rolled there may be stress in it thats all. so it should be good for heat treating the way it is?

[Doug Lester]

Ray may have different thoughts but I would wait and normalize the steel after I had the blade ground out just to relieve any stress from grinding the blade and to make sure the grain size is good. I'd do it right before I quenched the blade.

Doug

[Ray Rogers]

Nope, I don't have any different thoughts. Metal99 said 'anneal' and I doubt the steel needs to be annealed, it's ready to be HTed as soon as he profiles and/or grinds his blade. As Doug suggested though, normalizing as part of the HT process could be very beneficial ....

[metal99]

I usually normalize any steel as many times as it takes for it to hold its shape then I raise to above critical hold for a few and quench.

[Jacktheknife]

Y'all,


Someone please elaborate on normalizing?
This sounds like something that needs to be done to a blade with all the molecular stress in the steel. I could look it up and read about normalizing myself and I don't mean to be lazy but I sure would like a close up description of the normalizing process if Y'all have the time.


Thanks...


JacktheKnife
and just Dukedog

[WynnKnives]

Full Annealing, typically as I understand it, is when the steel is brought above its hardening temp (austenizing temp) and then slowly cooled in the furnace. This process brings the knife to austenite then slowly cools the steel so you have a completely soft uniform piece.

Normalizing you bring the steel fulling into the austenite temp and pull it out of the furnace. Much like a hardening quench but instead of quenching it you pull it out into room temp. So instead of cooler rapidly like quenching it cools slowly in air (unlike annealing, VERY slow)

Normalizing is good enough for major stress relieving, but does result in a steel that doesn't have a fully similar crystalline structure like annealing.

Now there's other types of annealing and normalizing but that's the basics.

Someone please correct me if I'm wrong, although I'm sure you guys will.

[metal99]

And hold your tongue right!

[Doug Lester]

One problem that can come about with annealing is that holding the temperature above upper critical as it slowly cools can cause grain growth. Normalization allows the steel to cool in air without any more of a soak than is necessary to make sure that the steel is fully annealed throughout. Of course, if the normalizing is done wrong, too high a temperature for too long, you can still increase grain size.

Normalization works to relieve stress in the steel by allowing the grains to reform and decrease to tension put on the atomic bonds within the crystals that were caused by forging and tooling the steel. Another way to say it is that it counters work hardening.

Annealing works by decreasing the size of and redistributing the carbides in the steel. Remember that carbides also includes cementite which is iron carbide. Because of cementite's association with other structures in steel, such as pearlite and bainite, it is sometimes considered as something separate from carbides. Annealing improves machinability more than normalization will but I've not found it to make much of a difference when it comes to grinding and drill a knife blade.

Doug

[AUBE]

With most steels I would normalize after grinding but on the 3/32" cold-rolled Admiral sells sometimes it comes with so much stress in it that the knife will warp like crazy when grinding. I've had some small 1" wide, 6-7" long blades warp enough when grinding that if you laid them down on your desk there would be nearly a 1/4" gap between your desk and the middle of the blade. It makes doing a straight grind nearly impossible. So far I only recall having this problem with the 3/32", so I've taken to normalizing before grinding.

Not all of it comes that way, but when it does its a pain in the butt to grind if you don't normalize first.

[metal99]

Thats some really good info you guys, thanks for sharing.

[ckluftinger]

Cold rolled steel has sharper edges, and usually costs more, too. Hot rolled has a coarse, somewhat dimpled, black surface and the edges are rounded. It's cheaper because it is easier to form, I suppose. I read the passages about 1095 with great interest as I, too, have my first batch of it waiting to be used...

[Jacktheknife]

Gentlemen,


About Normalizing:
Am I understanding that normalization is heating the blade till non-magnetic
then pulling it out and laying it on the ground to cool?
And I assume this doesn't affect annealing.


Thank you...


Jack the Knife

[ckluftinger]

I hope not to over-step my bounds, but as I understand it, you should not lay your piece down. This would cause uneven cooling (the area touching the ground would cool faster than the rest) and may cause warping. I heat my pieces to a very dull red, and then just hold them in the air, waving them back and forth gently until they have cooled off to where no red is visible. I do this three times before annealing...

[Jacktheknife]

cluftinger,


Of course, don't lay it on the ground, I {as usual} wasn't thinking.
But this is normalizing, to heat to merely dull red and hold the blade in the tongs till it cools?


Thank you...


Jack the Knife