Heat treat

[leftiye]

Hi, I just bought a commercial Mauser receiver that might not be heat treated. Does anybody know of someone who can tell me if it has been heat treated (test it)? Can one tell by using a punch maybe? Non treated metal should be similar to mild steel (I have some annealed 4140 to use to compare with). Does anyone know of a company that can heat treat it? Thanks, Ted

[Reg]

To properly do things, you really need to check the receiver on a Rockwell hardness testing machine. If you have been around heattreated receivers a bunch you can get a rough idea using a sharp punch but it would be very rough only.
Call the Brownells tech dept, I bet they know a source for a heat treater
Over the years there have been a bunch of soft and some actions that had no heat treat at all out on the market. Best to check, then pay to have it properly done.
Also the bolt needs to be checked as well.

:drinks:

[John 242]

I don't know of a 'field expedient method of testing the hardness of a bolt.

That being said, I came across this MidwayUSA video a little while ago:
http://www.youtube.com/watch?v=ZSBK3EwPE6A
Not the 'field expedient' method you are looking for, but at least it gives an overview of testing the hardness of a Mauser bolt and action, just in case anybody is interested.

Any machine shops, gun or knife smiths that may have a device like the one in the video?

By the way, the device used in the video appears to be exactly like this model from ENCO-
http://www.use-enco.com/CGI/INSRIT?PMAKA=505-1897&PMPXNO=953941&PARTPG=INSRHI

[theperfessor]

Many Colleges and Universities with engineering or technical programs have hardness testers (Rockwell and Brinell). They're pretty common pieces of material test lab equipment. Any places like that near you? If you lived near southern Indiana I'd be glad to do it for you.

Note: you probably shouldn't show up unannounced on a campus with a weapon!

[badgeredd]

Ted,

My suggestion would be to look for a tool shop in your area. Call around and ask if they have a Rockwell Hardness Tester. Once you find a shop with one ask if they could check a gun part for hardness. Of the dozen or so shops I've worked in 3 had testers.

There are some cheapie testers, but for the life of me I can't recall who makes them or who has them for sale. I'd imagine one of the tooling supply houses would have them. Also a thought that occurred to me is one could use an automatic center-punch to go with a comparison method. If I remember correctly, I am thinking that the newer actions are heat treated to somewhere is the mid to high 30s on the Rockwell C scale which really doesn't seem that hard to most of us. Perhaps John Taylor will chime in as he is more qualified to give a good answer on the correct hardness of receivers than I. Hope this is at least a little help.

Edd

[scb]

There use to be an outfit in Salt Lake that did re-heat treating of receivers. Don't know if they are still around. Problem is a lot of companies won't touch a job like yours unless you can tell them exactly what grade of steel was used to make the receiver. If one uses the wrong heat treating procedure on the wrong steel it can make your receiver as hard as glass, not a good thing. The other problem that can arise is warpage. If a company doesn't do the as a regular part of their business they probably won't have the fixturing to keep your part from getting "twisted". There are a lot of heat treating shops around, be sure to find one that knows what they are doing.

[Dutchman]

Military Mauser actions, for example, are not heattreated, they are case hardened. Case hardening and heattreating are 2 different processes.

Why would you think there's something incomplete about this "commercial" Mauser receiver?

Dutch

[flounderman]

there used to be a place in denver. I sent them an enfield that had been thru a fire. they would test it and treat it if it needed it. they did the bolt and receiver. check on the net for heat treating in denver, maybe.

[gnoahhh]

It's a dicey proposition to try to heat treat steel if you don't know the alloy its made of. Having it tested in a lab for its chemical breakdown is possible, but likely it would cost more than the thing is worth. A hardness test won't tell you much about its makeup. It'll just tell you if its 'hard' or not.

[nanuk]

Dutchman: is there any reason to "heattreat" a receiver if it is not heattreated, and NOT case hardened?

I would assume case hardening is not for longevity, but for the surface wear... would one need it for a sporter?

[Shiloh]

I don't know of a 'field expedient method of testing the hardness of a bolt.


Not sure I would trust this method.
to have 50K-60K pressure catastrophically let go would ruin ones day.

Shiloh

[largom]

Military Mauser actions, for example, are not heattreated, they are case hardened. Case hardening and heattreating are 2 different processes.

Why would you think there's something incomplete about this "commercial" Mauser receiver?

Dutch


Dutchman has it right, case hardened only. If you have a "commercial" Mauser it should be fine, no testing needed.

Larry

[theperfessor]

Case hardening s a heat treating process whereby the surface of the part is exposed to or in contact with a material that diffuses (permeates) into the surface of the part and to a depth that depends on a number of factors. When case hardening is done with carbon, it is called carburizing,, when it is done with nitrogen it is called nitriding.

Quench hardening is the process of cooling steel at a rate fast enough to prevent transformation from austenite (a face-centered cubic crystal that forms above about 1400F in most alloy steels) into ferrite (a body-centered cubic structure found in annealedd steel at temps below 1400F) by forcing it to turn into martensite (a body-centered tetragonal crystal that forms by rapid cooling). Untempered martensite is hard, strong, brittle, and not very tough. It will shatter from a shock load. That is why all quench hardened steels need to be tempered - reheated - after quenching. This reduces the strength and hardness a little, but really improves toughness and shock resistance.

Case hardening makes the surface harder and more wear resistant, and still leaves a tough inner core.

[405grain]

leftiye:

If you do decide to have your Mauser receiver case hardened, you could, if you want, have it color case hardened. This would give it a very distinctive appearance. No matter how you have your action heat treated, I strongly recommend that you have it done by someone who KNOWS what their doing. :-?

405grain

[nanuk]

thanks for the definitions Perfessor.

[W.R.Buchanan]

Find an inconspicuous place on the receiver, like on the recoil lug on the bottom. Run a file across it. If the file cuts then it is not hardened or not hardened very much. This may or may not mean anything.

If it is case hardened the file will just zing over it an not cut at all. If it cuts a little then it is probably heat treated well enough for the intended purpose. If it is a commercial Mauser action it is probably done right.

Most German Military Mausers are case hardened. The case is about .010-.015 deep on all exposed surfaces. Currently in the real world this is done by heating the part in an sealed oven to around 1500 F and injecting acetylene gas into the furnace. Since there is no Oxygen in the oven, the acetylene doesn't burn and the carbon in the gas penetrates the material. The depth of the penetration is controlled by the length of time the Acetylene is left in the oven.

The acetylene is sucked out of the oven before the door is opened so everybody doesn't blow up.

This yeilds a surface that is about 63 Rc. the interior is still soft, or as soft as Cro Moly gets which is still better than mild steels.

IF this is an Interarms Mark X action it is not heat treated very hard. However it is made of Cro moly steel so it is just fine for any cartridge it is designed to take, however it will wear faster if used alot, and it will enver have a really slick feel to it.

They made a really cool mini mauser action that was perfect for small caliber varmint rifles like .222 Rems. They had alot of complaints about them being soft. They don't make them any more, but I have never heard of one blowing up due to any fault of the action or the material. Idiots can screw up anything.

Try the file thing it is the quickest and easiest way to test to see if something is hard. I can't believe nobody said this in earlier posts. A punch will not tell you if the part is thru hardened or case hardened. Plus that you'll have a punch mark you can't get rid of. It is all needless if you are just trying to figure out if the metal is heat treated or not. It probably is to some degree.

Randy

[theperfessor]

The file test is a good idea Randy. I was doing a little consulting work recently testing the hardness of some items that were case hardened. Instead of specifying a hardness range on a particular scale the manufacturer used the phrase "surface to be file hard" on the print.

One of my suggestions to improve QC was to specify a hardness on an appropriate superficial hardness scale. They were aware of the limits of a standard hardness test when testing case hardness but weren't really onto the idea of testing with a superficial test procedure.

[Shiloh]

Good Info perfesser.

Gonna look int the terms you mentioned. Austenite, martensite, ect.

Shiloh

[Pavogrande]

IF, I recall correctly, milt mauser receivers were cased hardened from the inside.
A rockwell test to the exterior surface is not very meaningful.
I am with the others, a commercial action should not require heat treat, though I understand some of the santa barbara receivers are suspect as to their heat treatment. Apparently they were puchased by santa barbara untreated and the methods they used for treatment are suspect.
The operative phrase being " if I recall correctly"

[W.R.Buchanan]

Pavo: when anything is case hardened by the current method,,, All exposed surfaces are hardened. Inside outside and the edges too.

The only way to mask an area is to plate it with copper at least .002 thick. This is difficult to do on something as complicated as a receiver.

I have made cam roller pins for Indian motorcycles. They had a case hardened bearing surface and a smaller dia that had to be soft so it could be riveted into place in the rocker arm/cam follower.

The pins were turned oversize with the step on them. The step was turned to .004 under finished size.

The entire part was copper plated .002 on a side.

The copper plating was then centerless ground off the bearing surface still leaving enough material for finish grinding.

The parts were then case hardened by the method stated above.

The parts were then centerless ground to finished size for the cam roller to run on. The plated part of the pins was dead soft and the bearing surface was case hardened .020 deep and was 63 Rc.

Alot of planning went into these parts and they came out perfect, and are still the only source for cam roller pins for Scouts and Chiefs.

This was a simple 3/8 pin with a 5/16 step on it. Can you imagine how complicated a receiver would be to selectively harden.

Randy

[mstarling]

Douglas Barrels tests all Mauser actions they work on and require a minimum hardness before they will rebarrel an action. They use a Wilson Hardness Tester with a round rest. The action is placed on the rest and the test done on the flat just in front of the bullet ramp.

You may be looking for Blanchard Metal Processing Company in Salt Lake. See: http://www.bmproc.com/

I seem to recall that a place called Pacific Heat Treating or something like that also did or does Mausers.

[Clark]

I have ~100 Mausers and have been collecting them for 47 years.
I don't think the case hardening has much of anything to do with strength.
I do some over load experiments.
If I convert a 98 Mauser to belted magnum and do an over load work up, the lug abutments in the receiver start to push back and moving in to pinch the bolt body at the same bolt thrust that bolt body starts to get wider behind the bolt lugs on the bolt. That is ~ 107 kpsi in a belted magnum.
A few minutes of valve grind compound, and the rifle is working again.

http://i757.photobucket.com/albums/xx220/ClarkM/7mmRemMagantelope2011.jpg
I did that overload with this rifle and then shot a deer and an antelope with it in 2011.

The bolt thrust problem is separate and distinct from the case head failure problem.
I have blown the case heads apart 3 times, and all three times there were extractor parts and case parts that came back like projectiles at where a left handed shooter face might have been.

Jerry Kuhnhausen's book on double action Colt revolvers may be definitive, but IMHO, his book on Mausers sucks. Especially the part about heat treat.