Does the appearance of a hamon have anything to do with a target hardness?

Josh Rider

Josh Rider

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Would this be a correct statement?
Just because I have a hamon on my blade, doesn't have anything to do with the blades hardness as it pertains to RC number.

I'm asking because I've been trying to get better hamon activity with w2. I normalized (as best I could by eye and a magnet) then quenched in 8% brine. The file skates on the edge, tempered 2x @450, have Hamon activity.
But without a hardness tester, it could be anywhere on the scale right?
 
Not Really Related.
A hamon shows the transition between pearlite and martensite. That has no bearing on hardness.

It would show that the HT was properly done to get the desired effect, so if the HT was also designed to produce a hard edge, then that would also be expected ... but they are still two separate things.
 
There can be an effect, but it's if you push the envelope with really low austentizing temps. You might get less than the desires carbon in solution at the edge, but for non artistic applications, W2 will get a great hamon at ideal austentizing temps.
 
Yours is a good question, and i don't know the answer.
Actually i heard many lowering the austemp to get a better hamon activity, and if that's the case, as Warren pointed out, it could lower the level of carbon in solution.
Even then however you can get max hardness from above 0.6 C. I wonder then if the claimed increased activity has business with the carbon left to fine carbides.

Anyway the presence of the hamon, regardless its activity, say nothing on the edge hardness...it is not a visual proof of a satisfactory HRC number.
 
So would you say a better test would be by testing for chipping or rolling the edge?
If my end goal is a blade that has been properly heat treated. By following a proven procedure (thanks to the information on this site and those that contributed).

Without a hardness tester, how can I judge success.
Even with a hardness tester, you would have to test it on the edge of a clayed blade because the tang is going to be softer right?
 
You are correct. An edge test to confirm the HT results is the best non-technical test. The brass rod test is the standard, because it is repeatable with equal results pretty much by anyone anywhere. THe hT can be adjusted as you increase/decrease the tempering and make any other changes, and the new results compared to the previous. This way, once you have the HT parameters worked out, you can expect equivalent results from similar HT sessions. The test us also fast and cheap to verify that subsequent batches are all in line with previous tests.

Chopping, slicing, cutting, etc. all will indicate a good/bad edge, but the tests are subject to non-standardized variances.
 
Josh Rider said:
So would you say a better test would be by testing for chipping or rolling the edge?
If my end goal is a blade that has been properly heat treated. By following a proven procedure (thanks to the information on this site and those that contributed).

Without a hardness tester, how can I judge success.
Even with a hardness tester, you would have to test it on the edge of a clayed blade because the tang is going to be softer right?
Click to expand...

another quick test is after some bevel grinding and leaving the edge thick, is to see if it will cut steel
 
If you don't have an hardness tester the best is to see just how the edge performs...you will be either happy or not. It is that easy. The very edge it's a strong loupe on your steel's performances.
The brass rod test may come handy to compare the HT of 2 identical edge geometries, otherwise won't say much...not much more than just cutting with your blade.
Even if you get an hardness tester you need absolutely flat and parallel surfaces to be tested.
 
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