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

Okay guys,

As much as I hate to tell you this, please don't belittle those banned from this board. We are not letting back on to defend themselves!

Mark

I'm not belittling him, Mark. I actually miss the old boy.

case coloring
 

As I have stated before, the process of color case hardening is fully controllable for pattern and color range. There are many reasons that each of the manufacturers, using similar process recipes, yield such different patterns. We employ different formulas for each type that we case. Every facet of the process impacts the yield in various ways. Dr. Gaddy understood this and was able to target certain aspects. Unfortunately the original manufacturers did not document their process.
Surface preparation is critical. The majority of the manufacturers did not use coatings over the metal. I have never seen an original Parker with Lacquer on the receiver, Smiths were all shellacked thus the case appears to peal off with wear.
In the case where appearance is not the target, case hardening is still important to protect the metal.

Brad

Edgar casehardening depths vary from less than.0005" (speed case) to .030" (carburize) and is regulated by time and process. Spin Drift was right that casehardening doesn't make it stronger. I should have said that casehardening maintains strength while providing a hard surface.

Agreed. Have I said something to the contrary?

Edgar, earlier you commented along with myself and Michael Maffia that .002' depth seemed shallow to you and you expected depth to be .005' or more. In the past I have repaired 2 cracked receivers where I had to mill through the case which I found to be no more than .003 deep. I expect your experiences were different than mine.

Craig, you and Michael seem to differ on the Carbon content of plain carbon steel. I am most familiar with ASTM A216, as that was our daily bread and butter. That document indicates an allowable max C of .030%. A 216 (and SA216 for ASME) are cast steel specifications.
You give fairly broad ranges of case depths here, and indicated you found depths of .003". That would certainly seem to fall into, and at the lower ranges.

As I indicated earlier, Parker began using forgings containing higher nickels, and our spectrometer indicated, on a VH20 to be much closer to a .35C NiCrMo alloy. That VH 20 is floating around New England somewhere, and can be identified by the 5/16" dia. etched circle on the watertable. That was a gun I owned and I did the analysis in order to select an electrode, and repair a crack in the top tang.
Yes, my experience was different than yours, but I suspect if we both sampled many more Parker forgings, our experiences would cross, and vary significantly.
A sidebar I found interesting; Parker regularly purchased forgings outside, as well as running their own forge shop. One well know forge was the Collins Company, in Collinsville, CT, and Billings & Spencer, in Hartford. If Parker produced some of their own receivers, I don't know where their ingots came from, as they did not pour steel in their foundry.

Edgar I think Michael and I in total agreement. Michael sights 1008-1030 as low carbon steels which are not hardened. I state that plain steels with a carbon content of 0,4 and above can be hardened, anotherwords 1040-1095 can be hardened. The VH you note which had 0.35 carbon can be hardened but in order to harden it using only its own carbon you have to reach critical temperature (martensite) before you quench. I believe Parker added carbon to the surface and quenched at a lower temperature leaving the core soft.

This is your statement, word for word, in post #25

You keep refering to AISI numbers and implying that steels with C lower than .40% cannot be hardened.(although your words in red simply state that carbon steels must have a C above .40) Low alloy grades, such as AISI 8625 are certainly hardenable, and even 1020 can be quenched and tempered for Brinnels above 200.
I owned and ran a foundry that made, on average, 300-400 tons of Carbon, Low Alloy and Stainless per month. It was nearly all for power generation and Mil shipbuilding industries. I did it for nearly all my working career. Frankly, your nightly arguing semantics with me is annoying.