Jump to content
P.Abrera

Normalizing/Anealling

Recommended Posts

There's Gremlins in the forge!

 

There's Gremlins in the forge!

 

Oh lordy what can we do?

 

Don,... Jimmy,... Oh lordy! What can we do ???...

 

What I'm trying to say is,... "who gives a second thought towards their "ATMOSHPERE", in this thread?"...

 

You might need an atmosphere cleansing job or adjustment. :D

Edited by Tai

Share this post


Link to post
Share on other sites

Tai, I didn't mean to imply that Chuck needed to form a bainitic spine to make a good blade, it was just a question that occured to me. Again, if it was really necessary, a lot of bladesmiths would already be doing it.

 

Fatigue is generally a brittle fracture propagated by cyclical overload. I would not say it is impossible but I am not aware of classical fatigue failures taking place at forging temperatures. The steel is just too ductile at these temperatures to propagate a brittle crack.

 

Contamination of the steel by fuel, forge lining, etc., is a stretch for me. The contamination would have to be on an atomic scale to penetrate the crystal lattice of the iron. Carbon from poorly combusted hydrocarbon fuels might carburize a little bit. Sulfur from dirty coal is a possible contaminant but most exposures to dirty coal are fairly short. Possible, though. High sulfur steel is not very common any more so hot shortness is almost a thing of the past. Forge linings, not sure about what might do this. Silicates do not readily melt or vaporize at forging temperatures.

 

Forging too hot or too cold would be pretty easy, though and can crack your blade in a heart beat.

Share this post


Link to post
Share on other sites

All I'm saying is contamination of the forge lining and steel is possible. It may not be common, but it happens.

 

The type of fatigue I'm talking about may not be classic. I'm not referring to a brittle crack, but more of a "stretch mark", rip or tear in the steel. This usually comes from an abnormal amount of flexing or bending and shows on the surface in varying degrees, normally perpendicular to the edge.

 

Also just the stress from thermal cycling alone could eventually fatigue the steel, say if it were to be cycled several hundred times or abnormally.

 

There can also be mill flaws, impurities and inclusions in the steel which can create weak spots and brittle blades.

Edited by Tai

Share this post


Link to post
Share on other sites

Thanks, RK. That's a real compliment, coming from you. I need to give it another go.

 

Greg, I haven't seen any of the charts on crucibles L6, but I have a feeling that it forms bainite so easily that if you just marquenched it with the traditional clay coating, you would get a similar effect. Just need to see the charts.

 

Jesse

Share this post


Link to post
Share on other sites

Let's don't forget stress risers and the really far fetched "hydrogen embrittlement ".

 

What I'm saying is there are plenty of things other than abnormal or improper thermal cycling that can cause brittle blades. In the case of impurities, gas pockets and inclusions in the steel,... it may not be the smith’s fault at all.

 

Metallurgy can be such fun!

 

Have a nice day! :)

Edited by Tai

Share this post


Link to post
Share on other sites

Oh, yes, there are several things that could embrittle a blade: High sufur and phosphorus for example. Hydrogen embrittlement is transcient and the nacent hyrogen is driven off by heating to 250F. HOWEVER.....there is something called TME, or tempered martensite embrittlement, and this is actually fairly common. This used to be called the "Blue Brittle" phenomenon and occurs when you temper in the 500F-700F range.

Share this post


Link to post
Share on other sites

You don't hear much on blue brittleness these days,... cool! nice touch. :)

 

Yep, sulfur, carbon, phosphorus and hydrogen could embrittle a blade, huh?. What about a combination of two or more of them? Then what? All kinds of strange things can happen when you get these things going on with weird impurities and inclusions in the steel, coupled with abnormal thermal cycling, not to mention a soup of elements inside a dirty forge... Who knows?

 

That's why I try and keep it clean and simple . :D

Edited by Tai

Share this post


Link to post
Share on other sites

It's normal versus abnormal.

 

Imagine if you lived in a world where nothing was normal...

 

No normal people, no normal food, no normal air, no normal water, no normal laws, no normal governments, no normal WARS, ...no normal religion, no normal women,... no normal steel, no normal forge, no normal hammer, no normal anvil, no normal nothing,... THEN WHAT?

 

... normal is a breath of fresh air. :)

suck it on in...

 

Give me normal...

Edited by Tai

Share this post


Link to post
Share on other sites
Imagine if you lived in a world where nothing was normal...

 

No normal people, no normal food, no normal air, no normal water, no normal laws, no normal governments, no normal WARS, ...no normal religion, no normal women,... no normal steel, no normal forge, no normal hammer, no normal anvil, no normal nothing,...

23083[/snapback]

 

 

Wait, I thought THAT was the world we lived in! Hmmmm now I'm confused! :blink: Or maybe it's just California!

Edited by Michael

Share this post


Link to post
Share on other sites

It's amazing just what a good harden cycle in itself will do. I experimented with a scrap blade I'd buggered up the grind on when I first got my salt rig- went in the salt at 1500, held no more than 1 minute then quenched. No temper cycle at all. I found it wouldn't crack in normal cutting use, and it even took a fair bit of flex in the vise to get it to let go. The grain looked like gray silk.

Share this post


Link to post
Share on other sites
It's amazing just what a good harden cycle in itself will do. I experimented with a scrap blade I'd buggered up the grind on when I first got my salt rig- went in the salt at 1500, held no more than 1 minute then quenched. No temper cycle at all. I found it wouldn't crack in normal cutting use, and it even took a fair bit of flex in the vise to get it to let go. The grain looked like gray silk.

23090[/snapback]

 

Yep! :)

 

I've done some experiments with growing the grain abnormally large and reversing it in the hardening cycle. I think it works best with 10 series steels, as they seem to respond much faster. Of course I would never advise intentionally growing the grain, except for an experiment.

 

I have hundreds upon hundreds of working of knives in the field "being used on a regular basis", used hard by serious users,... for over 25 years now. So far, no one has ever complained about the performance of a Goo blade. In fact, they all say they cut great! I don't just make wall hangers...

 

I think this is the best test of methods. :)

(No brag, just fact.) :)

Edited by Tai

Share this post


Link to post
Share on other sites

Yikes!

 

I tried to plow my way through and ended up mostly scanning some of the replies.

I don't know if I misread or misunderstood or if what I am doing is different.

I noticed most here have stated they triple normalize after forging-I have always bought into the argument (mostly from my retired father-in-law) that we should be normalizing after grinding. His reasoning goes along with much of what I read concerning stresses in steel. Any stresses that can cause uneven hardening can be substantially reduced -even all but eliminated-with normalizing.

Granted that on knives I don't have to do a lot of grinding anyway. But on swords I do. I have routinely tested and fractured my blades for research and I am satisfied at the results I get with simple steels so I don't know if I will change anytime soon. Maybe I'm just getting old and stuck in my ways.

 

As we all know (so it wasn’t discussed much)- the welding cycles are high heats so we have to use finish heats in the lower ranges down to cold forming to re-fracture. If my father-in laws arguments are correct though- normalizing can be a substitute for that. To be honest, I don’t buy it that normalizing is panacea for all that ails steel grain. I will always forge to shape whenever and where ever it is possible. And I will normalize only “after" I have ground to shape. And that is just before heat treat.

But then I again I triple temper as well.

 

Maybe it is a bit of ritual. I'll buy that. I don't forge for money or as a living. I am simply addicted...heh heh. So, after a long day presenting to plannng boards and arguing and debating with conservation commissions .... a bit of ritual and hot fires in the snow at midnight I will attest too.

Gremlins?

My gremlins are water sprites!!

They usually only show up occasionally in the water when I put in a 30” katana. I know they are there when I hear and feel a snick!!

They did make me howl at the moon once with a particularly nice katana that I failed at. :unsure:

 

I think I need to get up to speed with salt baths.

 

Cheers

Dan

Edited by Dan

Share this post


Link to post
Share on other sites

If you over heat the blade while grinding, bend the blade or asymmetrically grind the blade, it will be a good idea to repeat the "straightening and normalizing" before hardening. This is because of abnormalities occurring during the grinding process.

 

You can avoid repeating those steps if you are "careful" during the stock reduction. This is why it is so important to "forge" the blade straight, symmetrical and minimize stock reduction, get the blade to set up straight right off, "reprogram" the steel... If a good job is done in forging to shape, the stock reduction can be done easily and quickly by hand without the heat and pressure of a grinder. To do a good job forging a blade to shape will most certainly come down to hand hammers. This approach can save a lot of time and energy contrary to popular belief that machines are more efficient.

 

One thing about being a "professional" is the importance of "efficiency". Professionals are not going to waste a lot of time and energy.

 

"The shortest distance between two points is a straight line."

Edited by Tai

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...