What the hell CPM 154?

I think we all agree that we have never had properly heat treated and finished CPM154 rust this easily.

The issue is - what is causing it on this knife?

On a side note:
I had a customer call me about a ring I had made last week. She was upset that the gold was bad, and was turning colors. She said it had a big dark spot on the gold. I asked her to bring it in. When she did, I looked at it, chuckled, and took my fingernail and popped the spot off - dried food:)
 
Nice timing, Stacy,

I literally just got some pictures from my friend about the same time you posted. I asked him to recreate the issue and I believe that the knife is reacting with his stainless sink. Some crazy rust at the point of contact over night, the contact may be forcing slighter rust in other areas. I'll post his iPhone pictures in a few.
 
OK,

What is this?

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thanks all.
 
The three words men find so hard to say... "I don't know" :D

Why would a stainless steel sink react with a knife blade? :confused: I still think there's some other factor causing that.
 
The sink is made of a different stainless steel ,a 300 series AFAIK . Stainless steel's corrosion resistance ,like some other metals depends on the oxide layer. If that is damaged you can get not only corrosion on the bare steel but even galvanic corrosion between steel and oxide layer. This effect can drill tiny holes into the steel ! Putting the knife into the sink risks other sources of corrosion.Take even a stainless steel spoon ,put a small drop of water in it , then sprinkle salt into it the spoon. The highly concentrated 'salt solution' should produce rust in a short time --it happened to me recently ,not by intent !! Other possibilities are there also. When finished with your knife wash, dry ,and put away .It takes only a minute and you'll never have a problem.
 
Thanks, mete. I clearly have a lot to learn about galvanic corrosion.

mete said:
When finished with your knife wash, dry, and put away. It takes only a minute and you'll never have a problem.
Click to expand...

I do know from experience that that works, whether the blade is "stainless" or not. :thumbup:
 
mete said:
The sink is made of a different stainless steel ,a 300 series AFAIK . Stainless steel's corrosion resistance ,like some other metals depends on the oxide layer. If that is damaged you can get not only corrosion on the bare steel but even galvanic corrosion between steel and oxide layer. This effect can drill tiny holes into the steel ! Putting the knife into the sink risks other sources of corrosion.Take even a stainless steel spoon ,put a small drop of water in it , then sprinkle salt into it the spoon. The highly concentrated 'salt solution' should produce rust in a short time --it happened to me recently ,not by intent !! Other possibilities are there also. When finished with your knife wash, dry ,and put away .It takes only a minute and you'll never have a problem.
Click to expand...

I think Mete has it. Everything he said is consistent with what's going on. I'm going to tell my friend to give me the knife for a while. If my mother in law can't wreck it, I think it's corrosion associated with the sink contact.

Thanks all, thanks, Mete.

EA
 
The stain looks clearly like galvanic action. It should clean off easily with a little stropping.
As mete said, it was most likely caused by some acidic food/liquid on the tip while the tip was in contact with the sink or some other utensil.
I have seen similar stains on stainless cutlery run through the dish washer.

The instructions I give with my knives say, "Rinse the knife and wipe dry when done cutting, then hand wash, dry, and put away as soon as is convenient. NEVER PUT IN A DISHWASHER."
 
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