Even wootz blades can break

Gt Obach · 11th April 2005, 03:20 PM

Hi Jens
5160 is a carbon steel which has up to 1%Cr and .6 carbon.... therefore it is a medium carbon steel that deep hardens...... it works excellently for swords and other long blades...

Cracking... the cracks are not the same ones that you find on some ingots ..... these cracks form as you are forging ..... they resemble the delaminations you find occuring with pattern welded blades... .
- you could remelt the whole ingot......but this would cost alot of money.... 30lbs of propane and 40.00 for the crucible for the remelt....... it is better to grind out the crack.... and continue forging..... which has worked for me in the past.....
-- you can never tell which ingot will turn out to be grumpy and disobedient....lol

- in one experiment.....i left the delam and made it into a sword..... it worked fine....just have a big line in the middle of the blade.... it is unsightly

Greg

Jens Nordlunde · 11th April 2005, 03:59 PM

Hi Greg,

Have a look at the picture. Close to the grip the watering is nice, but then it starts to change - why?

Jens

tom hyle · 11th April 2005, 06:22 PM

BTW, let me just say that it has never been my impression that great strength, in general, was the reputed high magic of the wootz/bulat, but the magical cutting edge?

Jens Nordlunde · 11th April 2005, 06:28 PM

Hi Tom,

I am not sure that I agree to this, but I will have to come back to it later, as I don't have any more time at the moment.

Jens

tom hyle · 11th April 2005, 06:41 PM

Thanks. I don't mean, BTW, to imply that when well made, they are especially weak; just I haven't heard they are extra-strong.

Gt Obach · 11th April 2005, 10:03 PM

Hi Jens
if you have a sort of blotchy area .....it can sometimes result from the way the blade way polished.... I find to get a decent etch you have to avoid burnishing the metal... this is why I like to use abrasive with a lube to wash away the cuttings...... if you load the abrasive up with metal it will intern burnish the surface and make the etch results inconsistent.
-- it is somewhat the same as polishing a japanese sword.... if you burnish the surface it will be extremely hard to see the hamon....

the blotchy areas can also be a result of overheating.... you can over heat a blade in local areas and it won't pattern as well..... or even loose pattern...... it could also be that there is a local area of decarburization... ?

-- sometimes you can have an incomplete melt..... by this I mean that all the charge ingredients you started out with aren't fully melted but are incased within the ingot...... this is a cruel surprise.... that you will only find out when you finish etching the blade at the end....

-- another critical problem is etching.... if the blade is not totally degreased.... and spotless.... you can have really weird streeks and odd irregularities
if your etch is not nice... then I think you miss the beauty of wootz...

I don't think of it as a super steel..... because it just works as good as my regular steel knives... but where it excels.....is the beautiful patterns.... and this is it's true magic

the above blade looks good..... it maybe that the steel was abit burnished in areas before the etch... (but this is just a guess)

the major blotches look like the blade was pulled out of the acid....and the drops of acid on the underside of the blade weren't wiped away.... so the drops kept etching...... this will give that blackened pattern...

- it doesn't look at all like cracking...... so it is a good blade

Greg

Jens Nordlunde · 12th April 2005, 02:42 PM

Thank you for your answers, it is most interesting.
Tom, I think that Indian blades famed by al-Biruni and al-Kindi back in the 8th and 10th century must mean something. They knew swords, probably used them too, so they would not fame a blade 'only' for sharpness, there must have been more to it than that, flexibility, hard to break, things like that. There must have been a reason why these blades were more expensive than other blades.

11th April 2005, 03:59 PM	#2
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Hi Greg, Have a look at the picture. Close to the grip the watering is nice, but then it starts to change - why? Jens Attached Images

11th April 2005, 03:20 PM	#1
Gt Obach Member Join Date: Mar 2005 Posts: 116	Hi Jens 5160 is a carbon steel which has up to 1%Cr and .6 carbon.... therefore it is a medium carbon steel that deep hardens...... it works excellently for swords and other long blades... Cracking... the cracks are not the same ones that you find on some ingots ..... these cracks form as you are forging ..... they resemble the delaminations you find occuring with pattern welded blades... . - you could remelt the whole ingot......but this would cost alot of money.... 30lbs of propane and 40.00 for the crucible for the remelt....... it is better to grind out the crack.... and continue forging..... which has worked for me in the past..... -- you can never tell which ingot will turn out to be grumpy and disobedient....lol - in one experiment.....i left the delam and made it into a sword..... it worked fine....just have a big line in the middle of the blade.... it is unsightly Greg

11th April 2005, 06:22 PM	#3
tom hyle Member Join Date: Dec 2004 Location: Houston, TX, USA Posts: 1,254	BTW, let me just say that it has never been my impression that great strength, in general, was the reputed high magic of the wootz/bulat, but the magical cutting edge?

11th April 2005, 06:28 PM	#4
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Hi Tom, I am not sure that I agree to this, but I will have to come back to it later, as I don't have any more time at the moment. Jens

11th April 2005, 06:41 PM	#5
tom hyle Member Join Date: Dec 2004 Location: Houston, TX, USA Posts: 1,254	Thanks. I don't mean, BTW, to imply that when well made, they are especially weak; just I haven't heard they are extra-strong.

11th April 2005, 10:03 PM	#6
Gt Obach Member Join Date: Mar 2005 Posts: 116	Hi Jens if you have a sort of blotchy area .....it can sometimes result from the way the blade way polished.... I find to get a decent etch you have to avoid burnishing the metal... this is why I like to use abrasive with a lube to wash away the cuttings...... if you load the abrasive up with metal it will intern burnish the surface and make the etch results inconsistent. -- it is somewhat the same as polishing a japanese sword.... if you burnish the surface it will be extremely hard to see the hamon.... the blotchy areas can also be a result of overheating.... you can over heat a blade in local areas and it won't pattern as well..... or even loose pattern...... it could also be that there is a local area of decarburization... ? -- sometimes you can have an incomplete melt..... by this I mean that all the charge ingredients you started out with aren't fully melted but are incased within the ingot...... this is a cruel surprise.... that you will only find out when you finish etching the blade at the end.... -- another critical problem is etching.... if the blade is not totally degreased.... and spotless.... you can have really weird streeks and odd irregularities if your etch is not nice... then I think you miss the beauty of wootz... I don't think of it as a super steel..... because it just works as good as my regular steel knives... but where it excels.....is the beautiful patterns.... and this is it's true magic the above blade looks good..... it maybe that the steel was abit burnished in areas before the etch... (but this is just a guess) the major blotches look like the blade was pulled out of the acid....and the drops of acid on the underside of the blade weren't wiped away.... so the drops kept etching...... this will give that blackened pattern... - it doesn't look at all like cracking...... so it is a good blade Greg

12th April 2005, 02:42 PM	#7
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Thank you for your answers, it is most interesting. Tom, I think that Indian blades famed by al-Biruni and al-Kindi back in the 8th and 10th century must mean something. They knew swords, probably used them too, so they would not fame a blade 'only' for sharpness, there must have been more to it than that, flexibility, hard to break, things like that. There must have been a reason why these blades were more expensive than other blades.