I awoke to a nasty surprise today. My new Damascus VG-10 blade had begun to develop fissures along the blade edge. I swear they weren't there yesterday and that I haven't dropped or mistreated it.
I've taken photos under 8x magnification so the fissures look big but to the naked eye they look like hairline fractures.
What could cause this to happen? How can the Damascus steel begin to de-laminate? As you can imagine, I paid a lot of money for this blade so I'm not very happy tonight.
Can any experts or metallurgists on this forum explain it before I throw this expensive knife in the bin?
BTW, the black dots and marks along the edge are dust particles
These sorts of blades are made in 3 layers. A center core of VG10, and two outer layers of inexpensive stainless damascus, one for each side. These outer layers are welded to the core. It looks like your sample was improperly welded or had some failure in heat treatment.
It should be covered by the manufacturer warranty.
As phatch says, there is a lamination line between the faux Damascus patterned cladding and the non-patterned core steel.
If you're saying that to the naked eye it's like a hairline kind of thing, I'm thinking that is normal. I would describe my Tanaka VG-10 nakiri as having the same trait. The line is far from the cutting edge of your blade and above the bevel. And naturally you wouldn't want soft stainless cladding getting even close to your cutting edge.
Can you take a picture of your knife non zoomed in?
As phatch says, there is a lamination line between the faux Damascus patterned cladding and the non-patterned core steel.
If you're saying that to the naked eye it's like a hairline kind of thing, I'm thinking that is normal. I would describe my Tanaka VG-10 nakiri as having the same trait. The line is far from the cutting edge of your blade and above the bevel. And naturally you wouldn't want soft stainless cladding getting even close to your cutting edge.
Can you take a picture of your knife non zoomed in?
Yes, the darkish hair-line starts above the middle of the blade, near the edge and extends for 1.5". The fissure follows the damascus pattern exactly.
Under magnification, most of the cladding around the rest of the knife on both sides is properly fused to the VG-10 core but this section appears to be lifting up. I guess most are as puzzled as me. Over the other side of the blade about a 1/4" length of the Damascus near the tip is also peeling away and there's another 1/4" length down near the heel.
I wonder if corrosion under the cladding is forcing it to separate from the VG-10 core?
I have a theory and it goes like this.... the knife was constructed with this fault and the fissures were present when it was first shaped and ground. When it was sharpened, grinding wheel sediment deposited into the fissures creating the illusion that the knife was ok. It then past quality control.
Once I received it, I began using it and through cleaning and use dislodged the sediment leaving the fissure open for all to see.
Why do I think this happened? I sharpened my knife tonight with a whetstone and the fissure disappeared. I tried to wash out the grinding sediment with high pressure water but couldn't dislodge it so now I'll wait and see what happens. If I'm correct, the fissure should return in the next week or so through regular usage.
This is the sort of thing that should have been spotted early on in the construction cycle. Makes me think these came from China. Mind revealing the brand?
This is the sort of thing that should have been spotted early on in the construction cycle. Makes me think these came from China. Mind revealing the brand?
I agree with you and I'm surprised that this one slipped through quality.
About revealing the brand, I'd prefer not to name this Japanese brand on this site as this is probably just a once-off occurrence and I don't want to do unnecessary damage in such a public forum.... for now.
I contacted the company today and they're going to swap out the knife but I'm going to hang onto this one for a few more weeks to do some tests on the steel (is it really VG-10?) and do some hardness testing.
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