Salt nitride treatment of rifle receiver, bolt, etc.

[MCMXI]

The technical term for typical salt nitride finishes found on some rifles, pistols and revolvers is ferritic nitrocarburizing and many of us are familiar with names such as Tennifer, Melonite, and Black Hat. I sent a Kimber 1911 to Severn's Custom seven or eight years ago to receive his Black Hat finish and he did a good job. I'm interested in sending out a couple of bolt action rifles so does anyone have any recommendations on a company that has done great work?

Thanks.

 

[js8588]

Nitride vs Ionbond is an interesting discussion. I happen to prefer ionbond as it doesn't mess with the temper of the steel.

http://www.jabuie.com/ionbond.html

 

[MCMXI]

Nitride vs Ionbond is an interesting discussion. I happen to prefer ionbond as it doesn't mess with the temper of the steel.

I remember reading something from Ted of American Rifle Company regarding salt nitriding receivers and bolts. Given that it's a surface hardening process that typically occurs at relatively low temperatures, is there evidence that it adversely affects the bulk material properties?

 

[troy fairweather]

What about edm

 

[MCMXI]

What about edm

Are you asking if EDM affects material properties. Typically a part will go to heat treat after EDM, at least that's what I've seen.

I called H&M Blacknitride yesterday. They do a lot of OEM work and can salt nitride a bunch of receivers, bolts etc. I sent them an email today asking about their process and how it might affect the hardness and toughness of a receiver or bolt.

After some digging I found the information from Ted at American Rifle Company.

https://www.americanrifle.com/shop/product/mausingfield-bolt-action-2

"An action needs to have a margin of safety to resist the dangerously high loads resulting from misuse. The margin of safety stems from both proper design and proper heat-treatment of the steel from which the action is made. Therefore, the Mausingfield action must never be subjected to temperatures above 400°F (204°C) for any reason, because doing so will significantly weaken it and compromise its safety margin. The Mausingfield must not be subjected to high-temperature surface treatments such as ferritic nitrocarburizing or salt-bath nitriding, because such treatments are conducted at temperatures ranging from 900-1200° F (480-650° C). These treatments are marketed under several trade names, including Nitrotec®, Tufftride®, Tenifer®, QPQ®, and Melonite®. While these finishes might be suitable for some firearms, they are not suitable for the Mausingfield and may not be suitable for other bolt actions either."

But interestingly, further down the page ...

"SURFACE TREATMENT

The Mausingfield is supplied with a salt bath nitride surface finish to harden and blacken its surfaces. The resulting finish effectively resists corrosion and reduces friction thus enhancing the smoothness of the action. The bolt head is coated with diamond-like carbon (DLC) surface finish. DLC is an extremely hard and wear-resistant layer on the exterior surfaces. This will reduce the friction between moving parts, thereby enhancing the smoothness of the action. DLC treated surfaces hold oil which enables them to resist corrosion reasonably well."

 

[troy fairweather]

Ya that's what I thought, they got beat threaded after, I have not looked into other coatings much tho. I guess the added costs is what keeps it mostly unknown. I see some custom actions do the edm, either the hole action of the bolt I've seen. I've only messed with hot bluing. But that's different.

 

[MCMXI]

@troy fairweather, EDM in my world is Electric Discharge Machining which uses a wire and current to cut metal. It's not a finishing process like DLC (ionbond).

 

[troy fairweather]

Dang I didn't even notice I got the letters wrong lol. Dlc think they call it diamond like coating. They do use dlc on some actions tho, think for the bolt bore or something.

 

[Demi-human]

Nitride+DLC=

Nitride relieves the stress in the barrel and provides a smooth uniform finish on the frame for the DLC’d slide to glide effortlessly on.

It felt nice, I did not get to shoot it.

With all the new coating and finishes and treatments and freaking sharks with freaking laser beams, I’m kind of over stainless steel...

 

[MCMXI]

I received a reply from H&M Blacknitride re their process and its affect on the heat treat of the parts. I provided the HRC hardness specs of the receivers and bolts I'd like to have nitrided and this is the reply I received this morning.

"I would have to run the 4340 and the stainless in separate batches. Stainless steel nitrides faster than carbon steel. also a standard process on the stainless 416 will not affect the core hardness. We will have to run a flash nitride on the 4340 to maintain the hardness. The end finish will look identical."

I'd only be sending 416 stainless parts out so if I proceed with this so I wouldn't expect any problems, only smoother running bolts.

 

[Demi-human]

We will have to run a flash nitride on the 4340 to maintain the hardness. The end finish will look identical.

Nitride vs Ionbond is an interesting discussion. I happen to prefer ionbond as it doesn't mess with the temper of the steel.

So there may be something to that then?
Only in an incorrectly done batch, I would imagine.

I love everything about my Aero nitrided bolt, and barrel. The barrel extension being nickel as well makes everything fall off with a spray of cleaner.
I’m sticking with it!

Furthermore, it seems stainless being easier, I could have a good many firearms re-done in black and have them even easier to clean.
Hmmm...