Hard chrome plating knives?

I work in an industry that hard chrome plates 4140 for abrasion resistance. We usually have about .010" thickness after finish grind. It is not pretty until it is ground. We have very little flaking unless there is an edge collision with the hardened alloy we are machining. I would be concerned about changing the dimensions and the rough finish of unground plating.
 
knarfeng said:
As a materials engineer who is a subject matter expert in corrosion, I'd rather have premium stainless than chrome-plated non-stainless. Less expensive, and you lose the toughness, which is one of the best properties of non-stainless alloys. Also chrome is galvanically dissimilar to steel. It will drive corrosion at the exposed edge. Even if the entire blade starts out chromed, the edge cannot remain chromed, because the chrome is ground off as you sharpen the blade. For this reason, if you are determined to coat non-stainless, you should coat it with a non-metallic coating.

Blades were chrome plated in the past because the knowledge of how to properly heat treat stainless had not yet been discovered.
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You can see the edge effect in vintage chromed kitchen knives where most of the blade is still chromed, but not around the edge.
 
brownshoe said:
You can see the edge effect in vintage chromed kitchen knives where most of the blade is still chromed, but not around the edge.
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That's where I saw the flaking in the chromed ceremonial dagger though the edge didn't look sharpened and was chromed all the way including the apex except where it came off of course.
 
LeatherStrop said:
What about using a sacrificial anode like zinc connected to the steel somewhere on the knife?
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As far as knives go, under normal conditions, galvanic corrosion is a non-issue due to lack of electrolyte. Just look at old knives, with all kinds of dissimilar metal parts like pommels, guards, pins, etc.

Might be an issue for diving knives or kitchen cutlery (dishwasher), but other than that, not much to worry about.
 
knarfeng said:
As a materials engineer who is a subject matter expert in corrosion, I'd rather have premium stainless than chrome-plated non-stainless. Less expensive, and you lose the toughness, which is one of the best properties of non-stainless alloys. Also chrome is galvanically dissimilar to steel. It will drive corrosion at the exposed edge. Even if the entire blade starts out chromed, the edge cannot remain chromed, because the chrome is ground off as you sharpen the blade. For this reason, if you are determined to coat non-stainless, you should coat it with a non-metallic coating.

Blades were chrome plated in the past because the knowledge of how to properly heat treat stainless had not yet been discovered.
Click to expand...

All wrench I use in my service is a hard chrome finish ..... Some are there for more than 30 years ...... I don t see any problem with corrosion on them :) they are even with very few scratches ..........hard chrome is hard :thumbup:
 
I would second that a hard chrome would most likely last if done correctly. They actually use it on piston rings, valves, and bearings.
 
knarfeng said:
As a materials engineer who is a subject matter expert in corrosion, I'd rather have premium stainless than chrome-plated non-stainless. Less expensive, and you lose the toughness, which is one of the best properties of non-stainless alloys. Also chrome is galvanically dissimilar to steel. It will drive corrosion at the exposed edge. Even if the entire blade starts out chromed, the edge cannot remain chromed, because the chrome is ground off as you sharpen the blade. For this reason, if you are determined to coat non-stainless, you should coat it with a non-metallic coating.

Blades were chrome plated in the past because the knowledge of how to properly heat treat stainless had not yet been discovered.
Click to expand...

I remember Mad Dog having a problem like this years ago with some of their hardchromed blades, and that was one of the reasons why they were phased out of SEAL team use. I'm not 100% certain, but I seem to remember the rust creeping under the coating, creating an invisible breakage hazard too.

Granted, SEAL team use is at the extreme end of the spectrum.
 
Well, I had several knives hard chromed over the years, It works but it just didn't seem to be worth the effort, just let em patina :D or go stainless.
 
FWIW I think it’s aesthetically pretty cool looking.

I have a Maxpedition large fish belly that has this over D2. I’ve only used to to clean large game exposed it to soap and water.

Anywho...keep pressing the boundaries man and experimenting with edges, steel types, and HT protocols. Cool stuff.
 
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