|
S |
M |
T |
W |
T |
F |
S |
|
|
1
|
2
|
3
|
4
|
5
|
6
|
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
|
21
|
22
|
23
|
24
|
25
|
26
|
27
|
|
28
|
29
|
30
|
|
|
|
|
|
|
2 members (montenegrin, SKB),
811
guests, and
4
robots. |
|
Key:
Admin,
Global Mod,
Mod
|
|
|
Forums10
Topics38,445
Posts544,840
Members14,406
| |
Most Online1,258
Mar 29th, 2024
|
|
|
|
Joined: Feb 2009
Posts: 7,463 Likes: 212
Sidelock
|
Sidelock
Joined: Feb 2009
Posts: 7,463 Likes: 212 |
....interesting stuff on the Temp. as well. Most things I have read call for a quench around 1450 F, I enjoyed Craig's post on the CSM video(which I need to track down) and it seems both CSM and ken's info come in at 1333 or so.... I think the 1450* quench is to harden the simple steel, minimal alloying, of the thin case. And, that temp is likely about right to form that hard skin that folks don't like to machine or engrave. The modern alloy likely in the CSM receiver may have the ability to through harden. So, they may be picking temps that don't change the properties of the steel too much in order to get the finish that they want on the surface. Since Ken brought it up, shielding and blocking techniques for parts headed for case coloring are tough to come by. What's also tough to come by is 'finishing', or what the 'freer's' did to actions/guns on final assembly after the parts came back from the case hardener. How was significant warpage, hideous gaposis,etc, dealt with accurately and without marring the finish. But, that's entirely something else, probably a career or three.
|
|
|
|
|
Joined: Jan 2002
Posts: 9,739 Likes: 97
Sidelock
|
|
Sidelock
Joined: Jan 2002
Posts: 9,739 Likes: 97 |
what about tempering? is that not the next step in the process, after the quench?
keep it simple and keep it safe...
|
|
|
|
|
Joined: Dec 2008
Posts: 277 Likes: 4
Sidelock
|
|
Sidelock
Joined: Dec 2008
Posts: 277 Likes: 4 |
Lots of great info.
Doug, nice work as always.
Ill throw my two cents in, about all its worth...
From my point of view, annealing is a necessity, not only does it make the steel softer, but also burns off a lot of garbage on the steel; rust etc. Makes it so much easier to clean up.
Carbon in steel is cumulative, every time a part is case hardened, you are adding carbon, annealing helps diffuse the carbon into the steel.
There is a reason that many, if not most folks practicing CCH today are not doing true case hardening. True case hardening temps are high, I have original recipes from a couple of manufacturers, temps that they were using are in excess of 1600 deg F. Thats ok if you are a manufacturer, you can afford a certain percent waste but for the modern guy, working on someones pride and joy, or a one of one gun, you cannot afford to make mistakes, and you cannot afford to crack a frame. Youve got one shot to do it right. So most will safe side it.
In my mind, tempering after quench is an absolute must. It relieves strains in the metal, and, allows the metal to be tweaked slightly. Remember, when cases hardening you are changing the temperature of the steel by more than 1000 deg F. The steel is going to move, and more than likely, you will have to move it back. Tempering will allow you to do this with less likelihood of cracking. I generally temper around 400 deg F, with little to no change in coloration.
I know some folks will say that blocking will prevent this; it helps, but it does not prevent movement. I use blocks in certain areas, on more than once occasion I have watched the parts move after the blocks were removed. Now I always temper with blocks in place.
Mike
|
|
|
|
|
Joined: Feb 2009
Posts: 7,463 Likes: 212
Sidelock
|
|
Sidelock
Joined: Feb 2009
Posts: 7,463 Likes: 212 |
....Carbon in steel is cumulative, every time a part is case hardened, you are adding carbon, annealing helps diffuse the carbon into the steel....
....I generally temper around 400 deg F, with little to no change in coloration....
....Now I always temper with blocks in place.... Thanks much Mike, I appreciate the comments. That annealing with temps high enough for carbon migration would make me wonder if wood charcoal pack annealing wouldn't drive more carbon towards the piece. It might be hugely disappointing if there were signs that carbon migrated out of the part. Thanks for the thoughts, worth keeping in mind.
|
|
|
|
|
Joined: Mar 2013
Posts: 2,862
Sidelock
|
|
OP
Sidelock
Joined: Mar 2013
Posts: 2,862 |
Lots of great info.
Doug, nice work as always.
Ill throw my two cents in, about all its worth...
From my point of view, annealing is a necessity, not only does it make the steel softer, but also burns off a lot of garbage on the steel; rust etc. Makes it so much easier to clean up.
Carbon in steel is cumulative, every time a part is case hardened, you are adding carbon, annealing helps diffuse the carbon into the steel.
There is a reason that many, if not most folks practicing CCH today are not doing true case hardening. True case hardening temps are high, I have original recipes from a couple of manufacturers, temps that they were using are in excess of 1600 deg F. Thats ok if you are a manufacturer, you can afford a certain percent waste but for the modern guy, working on someones pride and joy, or a one of one gun, you cannot afford to make mistakes, and you cannot afford to crack a frame. Youve got one shot to do it right. So most will safe side it.
In my mind, tempering after quench is an absolute must. It relieves strains in the metal, and, allows the metal to be tweaked slightly. Remember, when cases hardening you are changing the temperature of the steel by more than 1000 deg F. The steel is going to move, and more than likely, you will have to move it back. Tempering will allow you to do this with less likelihood of cracking. I generally temper around 400 deg F, with little to no change in coloration.
I know some folks will say that blocking will prevent this; it helps, but it does not prevent movement. I use blocks in certain areas, on more than once occasion I have watched the parts move after the blocks were removed. Now I always temper with blocks in place.
Mike Great contribution Mike, thanks. Any chance of a picture of an action with blocks in place? Are you recommending recoloring at lower temperatures, say around the 1333F temp that CS uses? Regards, Ken
Last edited by Ken61; 07/29/15 07:12 AM.
I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.
|
|
|
|
|
Joined: Feb 2011
Posts: 1,405
Sidelock
|
|
Sidelock
Joined: Feb 2011
Posts: 1,405 |
One must remember that blocks and fixtures only do so much. Since the braces are at the same temp as the part being colored, they are able to move among with the part.
B.Dudley
|
|
|
|
|
Joined: Dec 2008
Posts: 277 Likes: 4
Sidelock
|
|
Sidelock
Joined: Dec 2008
Posts: 277 Likes: 4 |
No, Im not telling you that 1331 deg F is where you should case, there are a lot of variables.
Quench water temp; big difference in results and drawbacks between 45 deg F and 90 deg F.
How big is your quench tank; does it have enough volume to quickly absorb the heat?
How far does the part drop after hitting the quench water; 14 inches vs. 3 feet can make a difference.
Is the water moving or stagnant? If moving, how, air or water pump?
What is the oxygen content of the water?
What is the hardness of the water? Softer water cools quicker.
Any additives?
Additives such as brine can actually cause the parts to cool quicker.
90% of this you learn via trial and error.
Its kinda like someone who has never driven before asking if 70 MPH is the optimum driving speed. Highway or back road, night or day, rain, snow etc you get the idea.
On blocks, take a look at the parts to be case hardened, you can pretty much figure out where they are likely to warp: generally thin areas. So side plates come to mind, also the tang areas where you have long thin pieces just hanging out there.
B. Dudley is absolutely correct, the blocks can warp. I make mine out of 304 stainless, make them as large /thick as possible. I had a block that I put between the rails on lever actions, the block was 3 inches long and about a half inch thick. After a couple of runs, it warped approximately .05
mike
|
|
|
|
|
Joined: Mar 2013
Posts: 2,862
Sidelock
|
|
OP
Sidelock
Joined: Mar 2013
Posts: 2,862 |
Thanks Mike.
Yeah, I've read about all of those variables. Besides the one's that have been mentioned in the previous posts. I'll just plan on extensive test runs and develop my own specific process.
One account I read was of Parker employees being encouraged to urinate in the quench water. I'm not sure yet if I'll be manipulating that one.
Regards
Ken
I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.
|
|
|
|
|
