hard chrome plating

N

Neo

Joined
Sep 12, 2002
Messages
1,283
Does hard chrome plating allow rust to build up under the coating?

I found these post about it:

And as Mad Dog found out...the bare steel exposed edge allowed rust to form UNDER the HC and blade failure from cracking was a possibility...
Click to expand...


The rust thing under hard chromium is a geometry effect rather than galvanic corrosion (Chromium is the more active metal, but only slightly, and the small beneficial potential difference can be overcome by the reaction kinetics) The nature of the chromium plate, especially when compromised, allows differential oxygenation corrosion (crevice corrosion or filligree corrosion -creeping fingers of rust) to operate along the microcrack between the steel and the chrome plate. This isn't driven by the chrome or the steel, but by atmospheric moisture and differences in the available oxygen at the tip of the advancing corrosion reaction.

Paradoxically, neither a more porous coating, nor a more strongly bonded perfectly impermeable one, would be so susceptible.
Click to expand...

Does this mean hard chrome isn't good for a high carbon steel?
 
I was a grinding machinist and a plater in a aircraft cylinder chrome shop for a lot of years and never saw rust under chrome.I really dont see why you'd want it on knife though.Also,you'd need very specialized equiptment to do it properly.And the city,county,state,and federal evironmental regulators will hassle you to no end.
 
Hard chrome should work well for protecting a carbon steel blade.
I have offered to do an electroless nickel test blade for an established maker. No takers yet.
 
bill, i know we have talked about plating a blade and one of these days i'm going to take you up on that offer :D. i just need to make a knife that i want to get plated.
 
I'm not a knife maker but I'm thinking of buying a knife.
Normally I dislike coatings on a knife, I like the patina on carbon steel knives,
especially with knives made from natural materials (wood, leather sheath)
In this case the overall look of the knife won't go well with a discoloured blade
This knife is made from some sort of 52100 (with a lot more carbon).
I quite like the hard chrome plating on it, but I don't want that the knife develops some sort of corrosion under the chrome

01.jpg
 
I forget the specifics and maybe I am talking about a different process, but in the off-road industry, parts that are meant to last are never chromed. There have been cases of the steel in shock shafts and other load bearing items failing due to the chroming process weakening the steel.

In the case of a knife I would never buy a chromed blade; if its shiny, it better be polished.
 
David66 said:
I forget the specifics and maybe I am talking about a different process, but in the off-road industry, parts that are meant to last are never chromed. There have been cases of the steel in shock shafts and other load bearing items failing due to the chroming process weakening the steel.

In the case of a knife I would never buy a chromed blade; if its shiny, it better be polished.
Click to expand...

Chrome and hard chrome aren't the same. Hard chrome is generally a matte finish, and it's MUCH harder that shiny nickel chrome.

-d
 
Plating doesn't make things shiny. It only coats the existing surface texture of the underlying metal. The work comes out the same texture, only plated.
 
Michael Lovett said:
Puma did is successfully for decades.

Mike
Maker
The Loveless Connection Knives
Click to expand...

I don't know what steel Puma used to have but this is a really high carbon steel.
(C-1.3-1.4%)
The maker brings it to bainite structure with high toughness an edge holding.
But the higher the carbon the higher the oxidation.
So what are your thoughts about this.
 
Just keep it sharp, and you won't have problems. If in doubt, oil the edge.
 
chrome plating will do you no good at the edge where it matters most. Once you sharpen it you're through the chrome

-Page
 
sunshadow said:
chrome plating will do you no good at the edge where it matters most. Once you sharpen it you're through the chrome

-Page
Click to expand...

:confused:

I don't see the problem at all.
I would just threat it like any other carbon steel not like H1
I consider the plating only to prevent getting a patina on the blade in this particular knife design
 
David66 said:
I forget the specifics and maybe I am talking about a different process, but in the off-road industry, parts that are meant to last are never chromed. There have been cases of the steel in shock shafts and other load bearing items failing due to the chroming process weakening the steel.
Click to expand...

Chrome is very brittle, and any load that puts the surface into tension (like bending) can cause it to crack. Those cracks then propagate into the steel. A tough steel probably won't snap on the first bend as a result of the crack, but it will break there eventually. Either from repeated loading or from corrosion forming inside the crack. I wouldn't want chrome on any blade I intended to use.
 
Seems there are a lot of plating experts here. How many of you have actually plated anything?
 
1973-1999 here.Mostly grinding old chrome out of a/c cylinders.But i did my tour over the tanks and ended up running the shop till i was able to escape.(-: Chrome is a great coating for steel.Kind of overkill for a knife,but what the heck,there's a lot of that.
 
You must log in or register to reply here.
Back
Top