HT doctors needed!...opinions please

C_Claycomb

C_Claycomb

Joined
Dec 11, 2000
Messages
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This is O-1. I etched it after taking it to a good 1200grit finish.

http://www.britishblades.com/forums/attachment.php?attachmentid=483
http://www.britishblades.com/forums/attachment.php?attachmentid=484

The blade got hard on quench, it seems to cut alright, and the edge doesn't chip when flexed over a brass rod, but I don't like the look of those silver flecks. I haven't had those in the other blades I have etched and I am wondering if I botched the HT, possibly over heated? It was edge quenched in some sort of Castrol HT oil that was used by the HT dept where I work. They said it would be fine for O-1 and I have used it on all my other blades without a hitch.

Any ideas what those little silver specks are? :confused:

Also, any idea why the spine and ricasso have faint tiger stripes?

Thanks.

Chris
 
Maybe those spots got decarburized, and therefore don't etch as well. Like XRAYED said, it probably got overheated.
 
Tiger stripes are alloy segregation which originated in the steel making process. You can't do anything about it. Can't say about the specks.
 
I think they may be on to something. Here is a quote from Stamasteel's (a damascus) heat treating recommendations: "Do not soak blades any longer than specified time, the steel will decarburize and you will not know it until you etch it."

Perhaps you did not get all the decarb grinded off before etching. You can grind and repeat etch.

RL
 
The specs could be something from your etchant. Been using aluminum or something as a hook for dipping your blade?
 
I really believe it is a sign of overheating....you can normalize the blade and try again. A long time back I had it happen with a 1084 blade of very thin stock.

It might be decarb on surface too...my guess again from overheat....you can go back to the belts then to hand finish...but I would really heat treat this one over again.

If you are heat treating in a forge...heat the tang end first and then flip the blade around so the tip doesnt get too hot right away....and keep testing with a magnet.

The good thing is that O1 is very forgiving.
 
I agree with the others. It looks like you overheated it. It could just be poorly made steel but the line is too well defined. Try it again and see if it goes away.
 
Thanks for all the input! I think that you are probably right that I did over heat, I have had problems on a couple other blades with them not getting hard. This time I wanted to be sure :rolleyes: oh well.

I don't have a grinder and don't fancy doing hand sanding to get rid of the specs, if the steel has been affected badly, grinding isn't going to solve it.

This was the second time I treated this blade, the first time the quench line was only 1/4 inch from the edge for about half the length. I wouldn't imagine that treating it again is gonna do anything good to it. If those specks are de-carburized, how will normalizing and re hardening help? Won't that just be taking carbon from somewhere else in the blade?

Out of curiosity, anybody know where to find a TTT curve for O-1, on the net or elsewhere? I know that it won't help my HT much, but I would still be interested.

Thanks again!!

Chris
 
How about bubbles. Was the blade completely degreased? Bubbles forming on the blade surface keep the etch from the blade hence spots. Maybe hit the 1200 again and agitate the blade so bubbles dont form. Might not work than again it just might.
 
I don't have enough experience etching but aside from that I believe he may have over heated it. It is worse to under soak than to over soak unless the temperature is too high. If the temp is too high soak time can hurt.

RL
 
The rehardening might help for the overheating problem but will do nothing for decarb. If you can't find the TTT diagram on the net Icould copy it from my book..... O-1 ,Hardening temp -1450-1500 F. Overheating can cause grain growth and hardening cracks.
 
ONly thing I don't get, is that if it is overheating, how come it seems to me(unless I"m misunderstanding pictures), that it's from spine back, but isn't really showing up on the edge and tip. Is this just from martensite/pearlite etching differently, or is it because the problem isn't on the edge/tip. And if it's not there, how did you manage to overheat the spine and not the edge/tip, as if you can control the heat that well to overheat thickest part and not overheat thin part, you're way better at this than I am. :)
 
oh no.....DOTS!

Dots,,,I had dots on one of my blades...

but I had then running along the cutting edge only...I never did fully understand where and why they came from, however I have a few hints...

As I said, My dots were running along the cutting edge and this hints of over heating. the dots were not seen before I etched the blade,,and once etched they were darn hard to grind out.

Buffing the blade did not seem to work, I needed to cut past the etch depth with my sanding belts...

the dots did disappear after the 2nd buffing,,,I believe that they might have been parts of the blade, that burned during heat treating,,,sometimes just for kicks I place some left over steel into my forge and heat it until sparks jump off of it, I am not sure but I bet that the sparks are the future dots after the quench?
 
I'd not be surprised if you had oil on your blade when you etched it, or have oil/grease/contaminant in your etching solution. Any of these things will cause a blade to etch that way.

Nick
 
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