Thank you Gentlemen:
We have tried faster oils, both Cheveron and Conoco Pale Paraffin and naturally faster oils like Brownell's tough Quench. None of them gave us results like the Type A, some cut well, but tough was not present.
Texaco type A is a heavy mineral oil, and there are light mineral oils, they quench faster. 'Utilty LV1 ISO22' is new to me, I will try to come up with some and give it a try, thanks for the information.
The more additives in the oil the quicker it will change its influence on the steel over using virgin oil.
We speed up Texaco Type A slightly by pre-heating the oil to 165 degrees f.
I learned this by accident when I was quenching several blades, the oil heated above the recommended 135 f. and the last blade cut better with greater toughness and strength.
The number of thermal cycles is also important, the more the better during the forging process as long as steel temp does not exceed 1625 f. especially when it comes to toughness. The finer the grain you develop, the lower the temperature where grain will grow, this is why multiple quench works so well, it is all related to time and temp.
Slow oil, I believe, is beneficial in that with 52100 and 5160 they keep changing over time, that is why 24 hour cycles during hardening and tempeing works so well. During the last seminar I hurried cycels to 12 hours. One medium sized blade flexed to 90 degrees with only 55 foot pounds force, I let it sit for 30 days and it took over 100 foot pounds to flex it to 180. This is why all my blades wait for finish grinding in my freezer.
The change cannot be explained by measured retained austenite, as there was none measurable, something else happens, but our laboratory equipment cannot evaluate it. The bladesmith can demonstrate the results by testing in his own shop with no equipment other than hemp rope, a steel rod to flex the edge and a torque wrench along with liberal quantities of tincture of time and a thick skin to avoid listening too much to critics are all that is needed.
There are so many variables to consider that one man cannot do it alone, the more who join in the quest the greater will be our success, thanks for the support.
If you have any more comments or questions feel free to join in.
