Traditional charcoal & bone case color

[Bruce Day]

We need Ed "The Torch" Good to come back and explain case colors.

[edgarspencer]

Originally Posted by Craig Budgeon

Edgar. you can not do a Rockwell test or a Brinnell test on a casehardened surface because the depth of the case is in the case of a gun receiver is less than .002 deep. Therefore when the diamond penetrator enters the casehardened surface it enters to deep giving a false reading. Casehardening leaves the inside soft which makes the component stronger. Carbon steels have a carbon content of 0.4% or higher and will harden through the entire part although the core will be softer than the surface

I Probably should have asked if he did Vickers hardness testing, but it would have been rhetorical. >oo2 sounds a bit thin, as compared to etch testing already performed. I would expect to see case depths of .005 or thicker.

Originally Posted by Michael Moffa

Carbon Steels usuaaly start with low carbon like 1008 and go up to 1030, medium carbon are 1040 to 1060 and high carbon is 1070 to 1090. Note the last two numbers refer to the decimal percent carbon content. These are simple unalloyed steels. Low carbon is not heat treatable per se but can be case hardened. The case depth is dependent on the process used and can be as little as .005 for nitriding and .010 for carbon packing and furnace heating. Gas carburizing can even go deeper.

Case hardening only makes the surface harder for low carbon steels. It does not make it stronger. What is the outcome of the process is a hard outer surface with a non-brittle tough core. Note that this is a very old process done with low tech steels.

This sounds too broad a statement, unless you know the chemistry. Soak times also affect depth.
Unlike many gunmakers, Parker used forgings with elevated nickel and moly, not plain carbon steel. Blindly heat treating anything without knowing its analysis can leave you with much deeper harness, and reduced ductility.

Originally Posted by Bruce Day

We need Ed "The Torch" Good to come back and explain case colors.

I KNEW someone would bring up good ole Ed's name in the conversation.
Admit it, Bruce, you miss him too, right?

[B. Dudley]

Originally Posted by Bruce Day

We need Ed "The Torch" Good to come back and explain case colors.

I think Ed was achieving better colors. And likey the same amount of warping.