Spots on my ZT350

[mikegideon]

That's some real good blade steel. Whatever is causing it can't be anything more than cosmetic.

[leroy]

Triple:___________

 

Been watchin this thread about the "spots".  When i looked at the picture again this mornin somethin hit me.

In the "old days" when i actually worked for a livin; one of my jobs wuz doin welding and fabrication related stuff.

One of the problems that showed up from time to time in stainless steel fabrication wuz a thing called carbon contamination of stainless steel.  S30v steel is a high grade stainless with about 14 points of Chromium.

 

In a nutshell, carbon steel tools, principally grinding tools used on carbon steel that have carbon steel particles embedded in them will sometimes "contaminate" a stainless steel surface and that surface will show a tiny bit of rust which is due to the small spot of carbon steel rusting on the surface of the stainless steel material.  Im sure that the s30v is "hard as a harlot's heart" (...it's a martensitic stainless steel...) and that these blades are ground to their final shape; or polished up some way usin surface and contouring grinders. 

 

My bet is that when they were "cleaned" (...i dont know how they do it...) for the DLC coating, that a tiny bit of carbon steel dust stayed, which i think is highly unusual in itself.   What ya are probably seein is a tiny bloom of carbon steel "rust" that cant push thru the DLC coating; it just discolors it.   The way we "fixed" these problems (...which were geneerally much bigger areas...) wuz to flapper wheel out the offending spot with a "clean" (...not used on carbon steel...) flapper wheel.  You dont want to do that to your DLC coated blade.

 

Havin said all that, its pretty much like Mike said above.  Outside of the little discoloration, its a "no nevermind".

 

Dont know if that's the problem or not; but it's at least a "could be" theory.

 

leroy

[CQB Elite]

I know this is old thread- my new Strider SA has very similar spots, actually one large spot. I wiped it with a silicone gun cloth and it faded but once the silicone dissipated it came back. I wonder if it's the coating since ZT uses same/similar? Also, could it be stains from the kydex sheath? Edit: I read Leroy's post above mine and his explanation seems to make sense.... Edited November 24, 2013 by CQB Elite

[TripleDigitRide]

Because the knife was a blemished model intended to be an EDC, I have ignored the spots. I do need to invest in a decent sharpener, however.