Steel turned blue???

[KnuckleDownKnives]

Anyome know why this may have happened? I used it to cut a pork loin, washed it off almost emediately and the steel turned blue. 15n20 steel.

 

[jdm61]

My suggestion? Cut up more pork loin. Cutting meat is supposedly a very effective way to force a patina and sometimes you get lucky and get that pretty blue color.

 

[Don Hanson III]

The start of a nice patina is what happened.

 

[KnuckleDownKnives]

Ok, thanks guys. My first kitchen knife and this type of steel, and never had anything better than a Walmart kitchen knife. Never seen one turn blue.

 

[jdm61]

A combination of blue, yellow, etc. that kind of looks like a faded case hardened firearm part is the ideal IMO.

 

[jdm61]

Thats because Wal Mart doesn't sell 15N20.

Ok, thanks guys. My first kitchen knife and this type of steel, and never had anything better than a Walmart kitchen knife. Never seen one turn blue.

 

[Mike22]

My Mora did that the first time I used it cutting up a case of chicken breasts. Thought it looked pretty cool.

 

[DevinT]

Experienced chefs who like carbon steel knives want that on their knives.

Hoss

 

[JTknives]

A2 will get that coloring when cutting apples

 

[E.Carlson]

Also 15N20. The owner called me thinking she ruined her knife. I now include a "what to expect" paragraph with my care instructions.

 

[Karl B. Andersen]

It was really dull. You sawed back and forth so fast the friction caused enough heat to lose the temper and turn the steel blue.
That's the only logical answer.

 

[stezann]

or it could be the massive amount of nitrites they use to preserve the meat and the heat form the friction...hot salt bluing!

 

[hhmoore]

Hopefully that wasn't a quick test before sending it to a customer...(it can be polished off, if it was)

 

[Natlek]

The start of a nice patina is what happened.

This knife /1.2519/ I made for my brother .Before I send knife to my brother /live out of country/ I give knife to my friend butcher to use several days .I told him ......use it on meat but no cleaning with water .To bad I did not take picture how it looks when I get back ........beautiful blue color ....forget I can not explain in english . My friend butcher use only stain CUT less knife and he did not want to give me back this knife , he offered me money as much as I could ask

 

[Greenberg Woods]

What actually causes the color, and all color in steel like straw, blue and purple during tempering is actually really amazing! Its a phenomena called thin film interference. There is no dye at all!
https://en.wikipedia.org/wiki/Thin-film_interference

 

[jdm61]

Is that similar to what you get when you anodize titanium?

What actually causes the color, and all color in steel like straw, blue and purple during tempering is actually really amazing! Its a phenomena called thin film interference. There is no dye at all!
https://en.wikipedia.org/wiki/Thin-film_interference

 

[Greenberg Woods]

Is that similar to what you get when you anodize titanium?

Yep. Same phenomena at work.

 

[AVigil]

It is the spirit of the animal absorbing into the steel

Or so I heard