I'm still studying the Japanese knives and must now prevent the different defects that could appear in this tool. I consider a high-carbon steel blade with a wooden handle, with the size of a Sakai Uchi Hamono knife (from 165 mm to 240 mm).
I must then find a non-destructive method to detect those defects before it's too late. Here is the list of methods I am allowed to use:
- Penetrant Testing
- Eddy current
- Infrared thermography
My main problem is that those Japanese knives are famous to be extremely well manufactured, and they have a life-time guarantee, meaning that they basically can't break... Nevertheless, let's consider 3 possibilities:
- The wooden handle gets a defect: highly improbable in my opinion since you only use it with your hand, without any particular stress on the wood;
- There is a problem between the blade and the wood: as you can see it in my previous question here, the two components are not simply stuck together. Knowing the shape of the knife and the strength of the steel, I can't possibly imagine how I can separate the two objects without applying a disproportionate force;
- The steel gets a defect. A "defect" would for instance mean that it doesn't cut properly anymore (maybe because of water when you need to wash it?) You can see how this kind of blade is forged here.
What kind of problem could I have, on the molecular scale for instance (fatigue failure ?) that would create such a defect? What kind of method in the list above can I use to find it?
Of course, if you find a potential problem linked to the handle, I'd be glad to hear about it.
PS: If you believe this is the wrong place to ask this question, could you please tell me where I should post it?