ladder pattern with shading

RSWORD · 3rd December 2006, 01:33 AM

Here is an example of a ladder pattern blade which has a dark zone in the lower half of the blade. From the first few pictures, it looks as though there is no pattern above this dark zone, however, as you can see from the final picture the wootz pattern is consistent throughout the whole blade.

Jeff Pringle · 3rd December 2006, 07:29 PM

Blades that have been partially transformed to martensite (by edge quench, or however) respond unevenly to the etching process - usually the hardened steel is more acid resistant, and the pattern etchs less deeply - but it depends on the type of acid, degree of polish, many variables.
Is there any difference in the depth of the pattern on this sword, or is it only a color change?

RSWORD · 4th December 2006, 12:42 AM

Hi Jeff,

It is only a color change. I have noticed that the color change is most prevelent depending on the angle of the light. As you can see in the last picture, if you get the right angle, the steel looks to be a homogenous color. However, when viewed at a different angle, the lower half of the blade shows a much darker coloration and the pattern has stronger contrast and you can barely see the pattern above this zone. From a metalurgical point of view, is something going on with light and how it reflects off the surface of the blade and how does angling the blade create a different look and color to the steel?

Jeff Pringle · 4th December 2006, 03:38 PM

Hardened steel will look darker than unhardened at the same level of polish, so that might be part of what's going on here. Usually, quenching also causes less contrast in the hardened area, but that ingot I made with relatively high phosphorus did not seem to suffer from a contrast drop in the hardened area.
I'm not sure about the metalurgic reasoning behind how the light reflects off the surface, but since the pattern is due to the structure of the steel, there must be some metalurgy beghind it, intermixed with the reflection mechanics of the polish level.

Gt Obach · 4th December 2006, 04:56 PM

Hi Jeff

that is so cool the the P slowed the contrast.... good to know..

i think that the acid in the etch eats abit quicker on the martensite.. ..so, more oxide and a darker pattern...

just my thinking ?

Greg

3rd December 2006, 01:33 AM	#1
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,086	ladder pattern with shading Here is an example of a ladder pattern blade which has a dark zone in the lower half of the blade. From the first few pictures, it looks as though there is no pattern above this dark zone, however, as you can see from the final picture the wootz pattern is consistent throughout the whole blade. Attached Images

3rd December 2006, 07:29 PM	#2
Jeff Pringle Member Join Date: Nov 2005 Posts: 189	Blades that have been partially transformed to martensite (by edge quench, or however) respond unevenly to the etching process - usually the hardened steel is more acid resistant, and the pattern etchs less deeply - but it depends on the type of acid, degree of polish, many variables. Is there any difference in the depth of the pattern on this sword, or is it only a color change?

4th December 2006, 12:42 AM	#3
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,086	Hi Jeff, It is only a color change. I have noticed that the color change is most prevelent depending on the angle of the light. As you can see in the last picture, if you get the right angle, the steel looks to be a homogenous color. However, when viewed at a different angle, the lower half of the blade shows a much darker coloration and the pattern has stronger contrast and you can barely see the pattern above this zone. From a metalurgical point of view, is something going on with light and how it reflects off the surface of the blade and how does angling the blade create a different look and color to the steel?

4th December 2006, 03:38 PM	#4
Jeff Pringle Member Join Date: Nov 2005 Posts: 189	Hardened steel will look darker than unhardened at the same level of polish, so that might be part of what's going on here. Usually, quenching also causes less contrast in the hardened area, but that ingot I made with relatively high phosphorus did not seem to suffer from a contrast drop in the hardened area. I'm not sure about the metalurgic reasoning behind how the light reflects off the surface, but since the pattern is due to the structure of the steel, there must be some metalurgy beghind it, intermixed with the reflection mechanics of the polish level.

4th December 2006, 04:56 PM	#5
Gt Obach Member Join Date: Mar 2005 Posts: 116	Hi Jeff that is so cool the the P slowed the contrast.... good to know.. i think that the acid in the etch eats abit quicker on the martensite.. ..so, more oxide and a darker pattern... just my thinking ? Greg