why industrial(black oxide)

[rwhite692]

....Channellock did away with chrome plating on it's products a long time ago, years ago.....

Really?

The various pliers have always been bare, though they still offer plenty of chrome-plated tools....Screwdrivers, Nutdrivers, etc

http://www.samsclub.com/sams/shop/product.jsp?productId=126240

 

[ptschram]

If the finish is properly applied, black oxide resists rusting better than chrome in damp and salty environments. The key is to hot oil treat them before putting them to use. All of the black oxide tools I've used in oilfield and exploration services held up much better than their chromed counterparts. Black oxide is just rust that has been boiled and then (usually) oil treated. The key is repetition and properly carding the converted rust. If you do that, you'll protect the entire surface and it wont rust further unless you scratch off the finish. Basically, you can't rust what has already been rusted. The black oxide is simply a protective shell of sorts. Nothing more than stabilized rust. Almost any gunsmith will tell you that a slow rust blue (black oxide) is superior to any other finish (except for maybe Parkerized). Got a rusty black oxide wrench? Boil it for 20 or 30 minutes, then card off the excess converted rust with oiled 0000 steel wool. Hot oil treat them and you're good to go.

There is a whole lot more to it than this.

First off, the "rusting" is a carefully controlled oxidation of the surface, one of the benefits of which (and one shared by "Parkerizing" metallic phosphatizing) is that the surface has many, many, many coarse pores to trap and hold oil.

Black oxide is achieved by immersing the steel in a boiling super-saturated bath of sodium nitrate, sodium hydroxide and sodium nitrite-depending upon the alloy, stainless requires more nitrite. This bath boils at around 300'F, IIRC.

Parkerizing OTOH is the deposition of manganese, zinc, or iron phosphate on the surface of the material. This is typically a VERY coarse finish that has some slight rust-resistance, but gains most of it properties by capturing oil in the rough finish.

Many of my professional jobs involved surface finishing and my dad and I owned a gun shop where we did bluing and parkerizing.

 

[Packard V8]

Do any of you use the the industrial finish just because you like them better? Anybody just cause you like them?

I've used the industrial finish Snap-on tools for almost forty years, mostly because I got a steal-deal on a new complete set which walked down here from the Alaska pipeline.

When it was time to add metrics, I had to look hard and bid high on eBay to get 3/8" metric sockets and combination wrenches in black. Interestingly, the new stuff is much more of a suede surface finish. The '70s tools were almost like a polished surface which was black oxide finished rather than chromed.

Because local garage/estate good buys occasionally came along, today, I've got maybe 1/3 of my sockets and ratchets in chrome.

The industrial finish sockets which have been used hard still look better than old chrome which has been punished.

As an aside, I've got a set of '30s-40s Blue Point combination wrenches. The chrome on them is still good, but nothing special. It is obvious they weren't doing a full-polish show chrome finish on wrenches back in the day. Around 1950, when they rebranded the wrenches Snap-on, they kept making them from the same forging dies. Anyone know for sure when Snap-on went to full-polish?

jack vines

 

[WHT]

Stronger and tougher would be a better way to describe impacts. But there is no way they can be "softer" or they'd never be able to withstand the daily high hammering or high speed torque delivered to them with impact guns. .

Sorry, but impact sockets ARE softer than conventional sockets and that is why they are tougher, more malleable and wear more. You can't have it both ways. A harder material will be more brittle and tends to shatter rather than yield under pressure.

I'm in the petroleum industry and we spend considerable time working with different steels in corrosive and high pressure environments. Hydrogen Embrittlement is another reason oxide surface treatments are used for some tools like impact sockets rather than chrome plating (very simple explanation below):

"Hydrogen gas enters the grain boundaries of a metal in the etching process and in inefficient plating processes like chrome. Hydrogen permeates the metal through its grain boundaries and over time weakens it.

The harder the metal, the more it will be damaged by hydrogen embrittlement. Hydrogen embrittlement has virtually no effect on cold rolled steel, but is a killer on fully hardened 4140 steel."

 

[sk1nner]

Ok, Ill give you some perspective on this from a platers stand point. No the black oxide finish does not have a better resistance to rusting, copper/nickel/chrome (standard chrome plating) will resist rust for alot longer a salt spray cabinet can and will confirm this. Yes black oxide does create hydrogen embrittlement, that's why at my shop we have to bake parts after black oxiding them. The only reason i can see for them to not chrome the "industrial" sockets its that in the professional work place cost and function override form. In other words they would rather have a lower cost piece that will work good, but not look as nice as apposed to having a pretty piece that works good but also costs more.

 

[ptschram]

Yes black oxide does create hydrogen embrittlement,

How does this occur at such a high pH?

If this were the case, it would not be THE standard surface finish for firearms.

I don't think this is the case for not only the chemistry but the temps involved.

 

[sk1nner]

PH has nothing to do with it. As an example cadmium plating is done at a very low PH and still creats hydrogen embrittlement. Nadcap mandates that we have to do H/E testing even on black oxide, and there are times that it fails. Say what you want, but with working in the field for many years (most of them in aerospace section) i know for a FACT that it does.

 

[GoBlue]

Generally speaking, high quality chrome plating doesn't flake even with abused or hard use. I've seen high quality plating on tool where the tool handle bent or twisted due to extream force and the chrome plating seemed to actually move with the tool without flaking (slight cracking could be seen, but no flaking).

Chrome plating as done by Danaher seems to peel and flake by simply looking at it.

What do you consider high quality? Ive got a KRL full of Snap on, Matco, Mac and ******** with flaking chrome due to abuse!

 

[ptschram]

PH has nothing to do with it. As an example cadmium plating is done at a very low PH and still creats hydrogen embrittlement. Nadcap mandates that we have to do H/E testing even on black oxide, and there are times that it fails. Say what you want, but with working in the field for many years (most of them in aerospace section) i know for a FACT that it does.

I would expect it at a low pH where there would be an overabundance of hydrogen ions (def'n of low pH).

Not all cadmium plating is done at low pH as some is done in a cyanide bath, just like some zinc and all gold.

Got any references to the AESF? I'm curious.

After doing some reading, it sure seems as though one of the benefits of black oxide is the almost complete absence of hydrogen embrittlement except in the case of extremely hard materials and some springs. I'm still curious as to what AESF has to say.

 

[WHT]

Yes black oxide does create hydrogen embrittlement, that's why at my shop we have to bake parts after black oxiding them. The only reason i can see for them to not chrome the "industrial" sockets its that in the professional work place cost and function override form. In other words they would rather have a lower cost piece that will work good, but not look as nice as apposed to having a pretty piece that works good but also costs more.

Some shops do experience hydrogen embrittlement because of inappropriate acid cleaning procedures and/or lack of knowledge; and NOT because of the black oxide treatment itself. Also, some shops use phosphate treatments instead of a true black oxide and they will also cause hydrogen embrittlement:

"No hydrogen embrittlement. Since Hydrogen is not evolved in the chemical process of black oxide coating, no hydrogen diffusion into the metal occurs."

"No hydrogen embrittlement: The black oxide process does not require an acid activation nor is it an electro-process; therefore, hydrogen embrittlement is not a factor. If the parts are scaled or rusty and an acid pickle is required, any hydrogen that may have evolved during the cleaning process will quickly dissipate in the black oxide tank (running temp. 285 degrees F). Any remaining hydrogen will be completely dissipated within 48 hours after processing. MIL-SPEC C-13924C Class 1"

"Black oxide passes highly accurate hydrogen-embrittlement test. Protective coating has no adverse effects on fastener life. Notched square-bar specimens are black-oxide coated and tested to failure to determine susceptibility to hydrogen embrittlement. Fastener manufacturers routinely apply a protective finish to bolts and screws that prevents rust and corrosion. However, there is some concern that plating processes can contribute to hydrogen contamination in fasteners, resulting in a potential for embrittlement. Materials undergo hydrogen embrittlement when atomic hydrogen is absorbed and diffused throughout the metal during electroplating or coating. Accepted theories of hydrogen behavior in high-strength materials stipulate that hydrogen is a mobile atom in the crystalline matrix of metals and will, over time, migrate to points of highest stress. This can eventually result in brittle failure. Generally, higher applied stress means shorter time to failure. And susceptibility to embrittlement tends to increase with the tensile strength or hardness of the steel. Thus, the very design of high-strength fasteners, with their many stress risers and notches and typical exposure to high dynamic loads, makes them ideal candidates for failure by hydrogen embrittlement. Hydrogen is an acknowledged by-product of many surface-treatment processes including black-oxide coating, and zinc and cadmium plating. Acid cleaning prior to plating is of major concern because it can generate hydrogen on the fastener surface. Plating can involve electrodeposition of protective materials, which can produce hydrogen. The processes also expose fasteners to various cleaning solutions and coatings, many of which have not been fully evaluated with respect to hydrogen contamination. One reason for a lack of information is that there has been a limited ability to measure hydrogen embrittlement. Recently, a method has been developed to measure the hydrogen-generating potential of coating and plating processes. This test gives a clean bill of health to a black-oxide coating."

 

[sk1nner]

After doing some reading, it sure seems as though one of the benefits of black oxide is the almost complete absence of hydrogen embrittlement except in the case of extremely hard materials and some springs.

This may be the case with what we process at my shop. As i said i work in the Aerospace aspect of plating, where EVERYTHING we process is high strength steels. It would just seem to me that good quality tools would be made of high strength materials, but i guess i was thinking that it was harder than it was. I was only going on my experience, sorry if i came off as hostile.

 

[Wakefield]

When we tried to electroplate something in High School science class I think I remember that bubbles came from the submerged metal object that we were trying to plate(I think with copper from whatever was connected to the other side of the battery).
Seems like I remember that the bubbles were hydrogen or oxygen?
Its been a long time--anode or cathode!

Wonder if hydrogen embrittlement had anything to do with some of those nice tools that broke at their flex joints that people posted pictures of on the Forum?

 

[sk1nner]

That could very well be. If the base metal is hard it has a tendency to hold the hydrogen. That was hydrogen you saw coming from the part being plated. Part is cathode (negative) other electrode was anode (positive).

Even a cyanide cad bath creates hydrogen though, that is what we use in my shop and H/E is a factor. Hell today while i was at work i had to run 5 sets of H/E test bars. I;m not trying to start an argument, as i said im just going on what we process at work, and what NADCAP/FAA mandates.

 

[ptschram]

I was only going on my experience, sorry if i came off as hostile.

I am also working from past experience and not trying to be hostile, however, truth is important.

Even a cyanide cad bath creates hydrogen though, that is what we use in my shop and H/E is a factor.

If hydrogen were being generated through this process, you'd be generating HCN gas and you'd have plating techs dropping like flies.

 

[sk1nner]

HCN gas is produced when acid (such as hydrochloric) is mixed with cyanide. The hydrogen produced during the actual plating (in the plating tank) does not carry much (if any) cyanide with it.

 

[ptschram]

HCN gas is produced when acid (such as hydrochloric) is mixed with cyanide. The hydrogen produced during the actual plating (in the plating tank) does not carry much (if any) cyanide with it.

You don't have much chemistry background do you?

 

[sk1nner]

I have enough to know how to work with my plating bath, I'm not going to argue this. If you don't believe (or trust) what I have learned from working with the stuff for years, that's fine, I guess you know every thing there is to know about plating, good for you. Have a nice day.

 

[ptschram]

I have enough to know how to work with my plating bath, I'm not going to argue this. If you don't believe (or trust) what I have learned from working with the stuff for years, that's fine, I guess you know every thing there is to know about plating, good for you. Have a nice day.

Look up Bastian Plating accident 1988.

I was hired by the insurance company to investigate how five young men died that day.

I understand plating chemistry.

I hope you don't make the same mistake those five young men did that beautiful June morning.

 

[sk1nner]

On the day before the accident, an industrial cleaning and hauling company pumped the waste from the tank, leaving a layer of zinc cyanide sludge in the bottom. At 4:30 a.m. on June 28, the night shift leader began preparations to clean the remaining sludge by spraying 1 or 2 gallons of muriatic acid (hydrochloric acid) into the drying tank

As i said HCL and cyanide don't mix well.

 

[KX250Fmotoracer]

I read somewhere that the black oxide finish on "industrial" tools is to battle the human version of what was called Crow's Syndrome.

The story was that real crows will swoop down out of the air and grab shiny things. The black industrial tool idea is to avoid having industrial tools (likely owned by the employer or job site) attract the attention of by-passers/spectators and disappear. Inside as well as out.

I'm no metallurgist or plating engineer. But I wonder if the absence of chrome plating on impact sockets has something do do with the stiffness. Are impact sockets softer but stronger to handle fatigue? But that chrome plating wouldn't stand up to that indefinitely so impact sockets are unplated?

Andy

I believe it. I doing an engineering internship over the summer at tier 1 automotive supplier plant. Often, the machine operators had to check bores of a couple runs of parts at a time.

Our go-no-go gauges were a glossy anodized red, green, with a blue handle. Couldn't keep the damn things at their stations for a whole shift haha. They looked similar to this:

The solution was to have the operators sign the tools out and make them liable for their return at the end of their shift.

I dont know what one would want with a plug gauge like that, theres no real use for them at home or in the garage... But they did look cool as hell!

 

[wafrederick]

Battery acid does eat chrome off too.Snap On's battery pliers are not chrome for this reason.