Damascus...hardness testing

Deweyknives

Deweyknives

Joined
Nov 29, 2006
Messages
1,097
Can you effectively and reliably Rockwell test damascus? Or is this one of those questions that 'depends on infinite factors'?:D

I've had the oppertunity to work with Damascus Dan [Seaver], heat treating some of his damascus. I'm happy to offer HT'ing for his customers 'in need', but I have to do some homework. I have a piece to make a test blade but would like to have some Rockwell tested also.

Anyone out there with a tester have time to work w/ me?
 
There's some argument for using Rockwell test files here. They're less precise than a indentation tester but the file will have to go across multiple different parts of the damascus. An indentation tester might give incorrect readings depending on just what's under the point.

While this was pointed out to me by a master with significant damascus experience I have not verified it personally because I don't yet make damascus (and am not willing to ruin the few bars I have from other folks until I get better).
 
Hey Dan. You the fella that I was talking to about visiting my shop, right? I would be more than happy to have you up and give you lessons on damascus and patterning if you would like. I'm no guru but some first hand learning would save you a lot of head ache and steel. :)

Also I do feel your right about incorrect readings, I think getting multiple readings at different areas would help by giving you the average. The nickle in 15n20 should help it harden but during the initial weld there is 4x more surface area per square inch than the 1084 causing a greater loss in carbon. Then again the carbon should even out as welding continues but I've heard that nickle steels are slower to diffuse their carbon to other bars.... To sum that up: I'm very interested in seeing the results.
 
From my experiance working with Devin Thomas and his damascus it depends upon the steel mix. A carbon and nickle mix will give you a composite reading of the hard and soft materials. A double high carbon mix will give you a pretty accurate reading on the hardness. His stainless mixes all seemed to give a acurate reading also.
 
Vickers Microhardness penetration tests of different areas will give you a believable and accurate way of measuring your individual layer hardnesses

-Page
 
Dan Seaver said:
Hey Dan. You the fella that I was talking to about visiting my shop, right? I would be more than happy to have you up and give you lessons on damascus and patterning if you would like. I'm no guru but some first hand learning would save you a lot of head ache and steel. :)
Click to expand...

Yep, that's me. Thanks a lot for the invitation, I am interested. When is a bit of a question because most of my next year's vacation will be used up by a family reunion in Oregon (opposite the ABS Maine hammer in, worse luck).

On the other hand, I've just started forging this year, made a grand total of three blades worth finishing so far. So it may be a while before I really need to start on damascus. But it looks like so much fun!
 
Thanks Dan P., I never thought about the files. Something to look into....................

Page, I don't think I've ever heard about the Vickers system. Do you have a source for testing?
 
To my way of thinking, the first variable to consider is the constituent steels in the damascus. If it's simple carbon steels (1084, 1095, 15n20, etc) that won't create a barrier to diffusion of carbon in the matrix, and your HT is done properly, a standard rockwell test should provide useful information. Note that I say "useful" and not "correct" or "accurate". that, again, depends on the steels used. For example, I'd say that in a mix of 1095/15n20, standard rockwell testing should be fine. I say that because neither 1095 nor 15n20 have additional alloying elements that should dramatically affect things. 1084 would most likely be OK, but I'm not certain what the effect of the Mn in the 1084 would be.

I suppose what I'm trying to say is that so long as the alloying elements in either steel that will not diffuse do not affect the hardness of the matrix, you should see pretty consistent readings across a test coupon.

Somebody please speak up and tell me if I'm wrong, but that's what my current understanding is.

-d
 
Deweyknives said:
Thanks Dan P., I never thought about the files. Something to look into....................

Page, I don't think I've ever heard about the Vickers system. Do you have a source for testing?
Click to expand...

http://www.matweb.com/reference/vickers-hardness.aspx

http://www.gordonengland.co.uk/hardness/vickers.htm

http://www.gordonengland.co.uk/hardness/microhardness.htm

Microhardness testing gives you a picture of what's going on in specific areas, which to my mind is much more relevant than doing one rockwell test in the middle of a flat area of a blade (generally the ricasso as that's the only parallel area) you can test a bright area, and an etched area in several spots near the edge which will give you a better picture of your edge heat treat, then do the same near your spine and at the tip which will give a much more realistic picture of your blade properties than saying "my ricasso is a rockwell 58 therefore my whole blade should be" When museums are evaluating historic weapons they will if they feel the need to determine hardness use the microhardness testing to determine the properties of individual laminates (See the Museum of London's "Knives and Scabbards" book where they analyze the metallurgical properties of a group of blades)

Hope this is useful

-Page
 
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