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Quenching oil help

i_r_machinist

Titanium
Joined
Apr 12, 2007
Location
Dublin Texas
I've read alot of posts about quenching over the last hour. I need to have the ability to produce hardened tools immediately. I made a tap with a thru hole in it out of 4140 and heated and quenched it in the only oil I had at the time. It worked but not as well as I would like. I've ordered some O-1 stock from MSC. The problem is I read a post about #2 quenching oil, and I can't find anywhere to buy it.

http://www.parkmetallurgical.com/park/products/oil_based_quenchants/oil_based_quenchants

This place has alot of oils. Can someone please point one out that would be suitable? I'm doing this with a rosebud in an open bay.
Thanks
i_r_machinist
 
O-1 is pretty tolerant stuff. I have quenched it in several oils from thick to thin. I would go with something thin.

It is really more important to get the oil preheated and the steel to the right temp than to obsess over the oil type IMHO.

That wasn't helpful at all...was it?
 
Heat your O1 part until it looses its magnetisum(sp?), heat your ouenching oil to
120*F and quench ouickley. I use automotive ATF, cheap and works well with O!.
Butcher
 
I use Quench-Tex 70 from Texico.
It is a comercial product that was given to me 20 years ago.
I use it on O-1 and have never had a crack or bad warp.

A good Sword or Knife makers book should have several sugestions. I've even herd of people using Olive Oil. Be prepaired to put out the fire!

Paulf
 
Automotive ATF + 25% kerosene by volume. Preheat oil to 125*F as stated above. Don't worry if you don't have a thermometer, just get it as warm as your hot tub! Works very well.
 
0-1 can make decent carbon steel taps. 4140 doesn't have enough carbon to make a tap for anything but very soft non-abrasive materials.

Industry used to be one of the largest markets for rapeseed oil and it was used for quenching steels. Years ago in a PR move to make it acceptable to a larger market (i.e. sell lots more of it) as an edible oil the producers in Canada changed its name to Canola oil. Your local supermarket carries it and it's not expensive.

Vegetable oils are biodegradable which is an advantage when it's time to discard them.

Without getting too technical, the cooling rate of quenching oil is directly related to its viscosity. Less viscosity ("thinner") achieves a higher cooling rate than higher viscosity ("thicker") oils. The cooling rate of a particular oil can be varied by adjusting its initial pre-quench temperature too.

With no idea of how large a cross-section of 0-1 you are heat treating it's not possible to make specific recommendations. Try the Canola oil at room temperature and evaluate its performance. Unless its a very large part it will work well. Use a large enough container of oil so that quenching your part doesn't unduly heat the oil up.

If you're threading the tap before heat treat be careful heating it. The thin thread crests are quite easy to overheat with an oxyacetylene flame. Use a soft flame and keep the rosebud cones away from the part. Also you'll be getting surface decarbonization during heating if it isn't wrapped. Keep the part enveloped by the flame to the extent possible to exclude air.

Don't neglect to temper the part properly.
 
I was watching the thread form very closely when I did this. Had a digital temp gun so the heat was right on. I didn't preheat the oil though, and it was a fairly cool night. I'll go with the canola oil as getting an msds approved is next to impossible here. What is pre-heating the oil doing for the operation?
thanks
i_r_
 
Preheating the oil slows down the quenching rate, the part cools more slowly than it would with cooler oil. For small cross-section parts it can help prevent cracking. It can also save poorly designed parts with abrupt shape transitions.

To achieve full hardness the cooling rate must be as fast or faster than the "critical cooling rate" for that particular steel. Small cross-sections cool much faster than large cross-sections so small cross-section items don't require as fast a quenchant as a larger cross-section part. Think of this way, it's an area versus volume relationship. Large surface area to volume ratio parts cool faster and vise versa.

We don't know how big your part is. As mentioned, 0-1 is a very forgiving steel. Have at it.
 
Qunching oil

I been using Kleband #100 for the last 48 years,when heat treating 0-1. I always heat treat a small 1 sq. inch block with my parts, drop the block in the first,for about 15/30 sec. then drop in my parts, constently sturring the oil. After removing from oil i let them stand untill hand warm.Then i anneal @ about 350/ 400 deg.f. I get a 60/62 rc.(drill fixture's)
Vinny D
 
I've been quenching parts in spotted owl oil for years. I used to use bald eagle oil but it smelled fishy after a while and you don't even want to guess what California condor oil smells like.

I tried Conservative oil but it's too hard to extract. Them conservatives wn't let go of anything that make them rich. I tried Liberal oil but filtering out all those bleeding hearts... Machinist oil - can't flter out the BS.
 
Quenching oil for tap

Do not use 4140 as it is not a cutting steel. An emergency tap can be made from O-1 or O-2. Heat to 1450 deg f. & quench in any common oil but keep it moving in the oil until it is just hot to the touch. Polish it up & draw the temper immediately while still warm to a medium straw color. Polish again & try to remove as much decarb as possible. You can then use this tap on most materials except tool steel
 
We use Esso Imperial Fenso oil grade 150.
We were having underhardening and some decarb problems all
summer as our Quench-Tex was 15 years old and evaporated half way down
from years of use for our small 01 tooling.
I personally would not play around with home recepies.
Decarb is our No. 1 enemy in our eat treating dept.
Hope this helps.
 
I use O-1 for most tooling that I make to use in my shop. I quench in baby oil that I buy from Walgreens on sale. It does not flare up, give off terrible smoke, nor obnoxious fumes like many oils. So far I've been extremely pleased with the hardening results. BTW - I temper the hardened tools in a small toaster oven. This system works well for me.
Jim
 
mostly what DaveE907 said. I use 30wt non degent thats been drained out a machine. I've never bothered to heat and its always worked...i completely understand that the temp of the oil affects quench speed, just that the quench speed at room temp has always worked for me using O1

As i understand it, what quench oil will do for you is have a different flash point so there's less risk of fire and less smoke...admirable qualities but the don't affect the effectiveness of the quench
 
I use plain mineral oil. No smell, no smoke, no flames, no excess carbon scale. It quenches clean. Same thing as baby oil but unscented... my tools do not smell like babies.

-DU-
 
We used automatic transmission fluid for several years in the toolmaker's shop. A 5 gallon bucket of it,and a bucket of brine were our quenches. We did not heat the oil up.

The oil does catch fire if a part as large as a plane iron is quenched.
we had a big hood with exhaust fans for that. As soon as the parts are warm enough to barely handle,a small toaster oven is used. I inserted a high temp thermometer with a long probe on it to make sure the temperature was correct.

The quench needs to be big enough that it isn't heated much by the quenched part.

Most blacksmiths heat up a bar of steel and quench it on cold mornings in the brine quench so as to not shock and crack water hardening steels.
 
The fire hazard seems to be based on exposed surface area of the oil. A 6 inch pipe, 3 to 4 feet long, welded to a slab of steel, and filled most of the way with oil, makes a great quench for smaller parts.

Years ago, I was running a small shop, and all the steels I used were air-hardening. A guy stopped by and wanted me to harden a few O-1 parts. Not really thinking, I got a 2 gallon bucket of oil out of the EDM to quench with.. I was lucky that there were a few fire extinquishers there..
 
I agree with Forestgnome, as well as the folks on the material issue. Your choice of quench oil doesn't matter if you are heating with a torch. Its like complaining about the lack of premium gasoline for your '82 Buick with 348K on the clock.

Anything you heat with a torch is liable to have a decarbonized surface. Heating in a reducing flame (about as much acetylene feather as you can stand) will help, but something like a tap that is all about sharp edges will always be difficult. A quick grind in the flutes before using will help remove some of the decarb surface.

I doubt you got your 4140 to RC50, while O1 should make RC60. That will make a huge difference in the performance of your tap.
 
I will try to post a series of images showing a typical (in my shop) tool hardening of O-1.

Hopefully there will be images of heating/soaking the tool, baby oil quench, after the quench, tempering, and sharpening. Enjoy.
Jim
 

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