5160 staining

[MilwaukeeJon]

Made a kitchen knife from 5160 and it seems very prone to staining. For example, if you slice an orange a dark stain shows up on the blade and almost looks as if there is very minor pitting. Any suggestions? I know that these can be cleaned and the blade oiled but is 5160 known for this problem? 

[JHCC]

Pretty much any non-stainless steel will have this problem. If you want a knife to remain forever pristine, clean it and put it in a case. If you're going to use it, though, embrace the natural patination!

(Just remember to clean and oil religiously after every use, especially when cutting acidic foods like your orange.)

[Joël Mercier]

A good polish + butcher's oil or wax will help but there will always be a patina on the long run

[ThomasPowers]

Just went and looked at a Kabar butcher knife my Mother gave me---it was her 2nd anniversary present from back when they were poor and she didn't have a good knife for the kitchen.  Well that was about 61 years ago and it has a tight adherent patina.  No letting it soak in the sink, no putting it in the Dishwasher!  Wash, dry and a quick wipe down with a food grade vegetable oil.  I expect I'll be passing it on to a grandkid of my own some day...(It's sitting in the drawer with the other old plain carbon steel knives that I acquire whenever I can find them at a good price---sometimes needing rehandling; but that's not an issue!)

[rhitee93]

To some extent, the patina helps slow down rusting.  It also tells the story f the knife.  When I give a kitchen knife to someone I tell them that it will oxidize with time, and not to fight it. The grey/black oxides are the good guys, and as long as it isn't red rust it should be a welcome addition to the knife.

Of course, I hand polished my first kitchen knife to a P2500 grit finish.  I learned not to do that after the first use.  That was a bit heartbreaking