wootz with interesting "striping"

RSWORD · 3rd December 2006, 02:28 AM

This is an interesting example in that the wootz pattern has "striping" throughout the patterning. I would be interested in what is causing this.

Jeff Pringle · 3rd December 2006, 08:15 PM

I think those lines are the remnants of the primary dendrites, the first steel crystals to solidify from the melt. If the melted steel is cooling very slowly through the liquid/solid transition, the 'trees' can get pretty big. They make it through the forging process to one degree or another depending on size, how much elongation happens and if the ingot is heat treated to diffuse the alloy content or not.
Figure 1c on page twelve of Figiel's "On Damascus Steel" shows an etched ingot, the dark lines you see on that face are the primary dendrites.
I'll see if I have a photo to post...

RSWORD · 4th December 2006, 01:46 AM

Jeff,

I have a copy of Figiel's book and see what you are speaking of. It makes for an interesting feature to a wootz blade. Structurally, any disadvantage to having too many "trees".

Jeff Pringle · 4th December 2006, 04:51 PM

Quote:

Structurally, any disadvantage to having too many "trees"

No, I suspect they have no effect on the blade's structural state, too small in relation to the blade's cross section. Since the first steel to solidify is most pure, it would also tend to be the least brittle in the finished blade, so if there was an effect it would be towards increased toughness. Since the carbides don't collect in them, they might cause microscopic dull spots on the edge? Probably not significant to overall edge performance.

3rd December 2006, 02:28 AM	#1
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,083	wootz with interesting "striping" This is an interesting example in that the wootz pattern has "striping" throughout the patterning. I would be interested in what is causing this. Attached Images

3rd December 2006, 08:15 PM	#2
Jeff Pringle Member Join Date: Nov 2005 Posts: 189	I think those lines are the remnants of the primary dendrites, the first steel crystals to solidify from the melt. If the melted steel is cooling very slowly through the liquid/solid transition, the 'trees' can get pretty big. They make it through the forging process to one degree or another depending on size, how much elongation happens and if the ingot is heat treated to diffuse the alloy content or not. Figure 1c on page twelve of Figiel's "On Damascus Steel" shows an etched ingot, the dark lines you see on that face are the primary dendrites. I'll see if I have a photo to post...

4th December 2006, 01:46 AM	#3
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,083	Jeff, I have a copy of Figiel's book and see what you are speaking of. It makes for an interesting feature to a wootz blade. Structurally, any disadvantage to having too many "trees".