Effect of oil volume and agitation in quenching?

[Justin King]

Scenario:
I am going to through harden a 1084 blade. Normalizing and austenizing cycles will be done in a digital oven.

I have 2 choices for quenching, both are vertical tube tanks. One is 3.5" diameter, has no agitation setup and is filled with Brownell's Tough Quench, approx. 1 gallon total volume.
The other is 6" diameter, has a recirculating pump system for agitation, and holds approx. 3 gallons of Parks AAA.

Which one would you use?

My understanding is that the Tough Quench is faster than the AAA and would be better suited to 1084, but how much difference in quench speed and efficiency should I expect based on the difference in volume and agitation alone? Anyone care to hazard a guess?

 

[Remyrw]

One blade? I'd say you're ok with the smaller container, just a bit of up and down agitation to reduce vapor jacket formation. From what I've read that's not a real issue with Tough Quench or Parks.

 

[Russ Andrews]

AAA is a proper quenchant for 1084.
Within reason...It's better to go with the larger volume
of quenchant, not only for speed, but also uniformity.

so...the larger container with AAA is better.

 

[Rick Marchand]

I don't think i would ever make a tank that would hold less than 5gal of quenchant. 3.5" dia is too small, imho. You need volume to pull and dissipate heat.

http://www.bladeforums.com/forums/s...-priciples-of-quenching?p=6740851#post6740851

 

[Stacy E. Apelt - Bladesmith]

In a quench tank, within reason, bigger is better.

Engineering wise, the optimal tank needs a volume of 400-500% the blade width by 150-200% the blade length. On a folder, this works out to be a gallon, on a 2X16"bowie, it is 10 gallons.

For general shop use, the best tank size to build is 6" wide by 24" deep. That takes three gallons to fill.
A better tank is 8" by 24", which takes about five gallons.
An 8"X48" sword tank takes 10 gallons.

Pumped agitation is a nice thing, but unnecessary in all but a commercial shop. Volume takes care of the situation nicely for most of us small batch makers.

Some notes about building quench tanks:
They should be metal and sturdy. Never make a quench tank from glass, plastic, or thin metal ( like a 5 gallon cooking oil can). They can all fail too easily.

The tank should have a base that is at least 50% the height, and 200% the diameter. A 24" tall by 6" wide tank should have a minimum of a 12" base plate. This is to keep the center of gravity low enough to prevent the tank from easily tipping over. The simplest method is to make the base of the tank from a larger plate than the tank pipe upright, but even a plywood base with triangular gussets will work.

You can weld a tank up yourself from pipe and steel plate. Grind the joint end of the pipe to a 45° angle from the outside, and make good fillet welds.

When building any tank above 1 gallon in size, weld on a 1/2" or 3/4" pipe fitting , and install a drain valve. It is a lot easier ( and less messy) than lifting and pouring 5-10 gallons of oil into a storage pail. You should occasionally drain and filter your oil, as well as clean out the tank. Taken care of, a five gallon pail will last for 10 years.

Weld handles on both sides of the tank, and make a snug fitting lid. This is a requirement for safely quenching. It also keeps pets and other critters, as well as debris and moisture out of the oil. Putting wheels on the base will make rolling the tank out for use ,and away for storage, easier. ( Note- the measurement for COG is made from the bolt hole distance of the caster bolts, NOT the base plate size)

Ready made tanks can be found in all sorts of places. A 5-10 gallon scrap water heater from the local plumber, a five gallon soda syrup tank, various large cooking pots, large ammo cans and other military storage containers, old compressed gas cylinders, beer kegs, etc. Some of these will require cutting off one end, or cutting a hole in the top. Others may be fine as is. A visit to the local scrap yard usually turns up all sort of neat quench tank possibilities. A fellow I met in Atlanta has the fin portion of a practice bomb as his tank...way cool.

 

[JMJones]

also the siphon hand pumps sold at automotive stores are great for getting the quenchant from a storage container into your quench tank if you dont want to store it in the tank. i store my parks 50 in a 5 gallon pail with a lid and siphon it in and out of my quench tank as nessesary, takes less than a minute.

 

[Stacy E. Apelt - Bladesmith]

Yes, they work well. However, I would use a stopwatch next time, as they only transfer about 1.5 GPM...so it should take three or four minutes