case hardening question

[hawaii five-0]

When using the oil quench meathhod of case hardening,do you do the water first,then the oil?Or is it the other way around?

[Mikeb]

When using the oil quench meathhod of case hardening,do you do the water first,then the oil?Or is it the other way around?

A little clarification might be in order. What do you mean by the oil quench method? Water is usually used with case hardening. The case harden piece is then ready to go. The base metal is still mild steel so it is not brittle. Oil is used to quench high carbon and alloy steel to prevent too rapid a cooling . At that point the work is hard all the way through and is tempered by bringing it to the temper point. That can be quenched again or left to cool. The temperature it gets to in tempering will determine the hardness of the part.
I don't think that answers your question.
take care
Mike

[Sky_DiveR]

Hey five-0, wassup? Long time no hear.

Are you talking about an AK receiver?

Mikeb, so what you're saying is that if you quench the receiver in oil after you heat it, you need to temper it but if you use water/salt solution, you don't have to temper it? Could be the reason why we're having to case-harden again using the water quench (especially on the ejectors). We're reheating and air cooling to temper after the water quench which, if I understand you correctly, isn't necessary?

[Mikeb]

Hey five-0, wassup? Long time no hear.

Are you talking about an AK receiver?

Mikeb, so what you're saying is that if you quench the receiver in oil after you heat it, you need to temper it but if you use water/salt solution, you don't have to temper it? Could be the reason why we're having to case-harden again using the water quench (especially on the ejectors). We're reheating and air cooling to temper after the water quench which, if I understand you correctly, isn't necessary?

Like I said I'm not sure I understand the question. Case hardening is used to put a hard wear resistant surface on a piece of steel that doesn't contain enough carbon to harden. Take a nail... heat it till a magnet won't stick then quench in oil or water. What do you get? pretty much what you started with. The nail doesn't have enough have enough carbon to harden. now take a nail and bury it in charcoal or better yet cover it with case hardening compound. Heat it to the point a magnet won't stick and quench. What have you got now a nail with a very hard surface. A file will not cut it. Now that hard surface is only a few thousandths thick. If you grind off the case what do you have? you're back to the soft nail. The case can be made thicker by "soaking" the part at the high temperature for more time. Water quench will be harder than oil...I think. My can of Kasinet recommends water. If you are trying to case harden and it is not working my guess would be either it's not hot enough or the oil quench is cooling too slowly.
Is that clearer?

[hawaii five-0]

Let me rephrase my question.I am trying to harden a piece of 16 gauge mild steel to use as a trigger guard on my saiga 12.Please explain the process.

[Mikeb]

I am trying to case harden a piece of 16 gauge mild steel to use as a trigger guard on a saiga 12.Maybe this is more complicated than I thought....

No I think you can handle it. What materials are you using? Though I would wonder why you want to case the trigger guard... but that's your business. If you are using Kasinet or something similar try the instructions on the can. If your looking for colors that's a bit different. You might want to cruise the Brownell site. they have a lot of instructions on there somewhere.
If that doesn't work I'm sure someone here can put you on the right path.
take care
Mike

[tujungatoes]

I think you're over thinking this whole thing. it's just a trigger guard. it's not really a structural/high stress part. why the need to harden it?

[hawaii five-0]

I guess I am.The original one was hardened(I know 'cause I tried to drill through it),so I figured I'd try to harden it.

[tujungatoes]

hey man i'm not sayin' you shouldn't. I can't think of a reason not to. Just that if it was me, I wouldn't bother. I'm lazy like that

did you make this thing yourself? if so, lets see some pics. it sounds like a cool bit of fab.

[SJgunguy24]

I guess I am.The original one was hardened(I know 'cause I tried to drill through it),so I figured I'd try to harden it.

It wasn't case hardened, it was heat treated. That is what Mikeb was talking about when describing the heat and quench process. Kasenit is a carbonization treatment of the surface that can be done at home.
True case hardening is done in a furnace and the metal to be hardened is packed in a sealed box with the carbon bearing material and is cooked for a prescribed amount of time to reach the desired depth of hardening.