Quenching oil question

BobbyD

Well-Known Member
I have this posted on another forum but hopefully you all can help as well

have a heat treat oven on order. I want to start out with oil that will get me the best results but I would like to use just one type of oil. From what I have read Parks # 50 and AAA are often used. Parks 50 seemed to be used the most. So what Carbon steels can be used with #50 and what steels need AAA? I have 52100 and 80crv2 And have used 15n20. I won’t be HT a lot of blades at a time just a few. I would like to try W2 and 26c3 in the future. Is a one gal tank enough of oil to do 2 or 3 blades at a time Before the oil gets to hot?
Also do you guys use your HT oven to temper?
thanks
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Kevin R. Cashen

Super Moderator
Park Metallurgical, HeatBath #50- any 10XX, i.e. 1070, 1075, 1080, 1084, 1095, W-1, W-2, 15n20.
Park Metallurgical, HeatBath AAA- alloys steels, (oil hardening), i.e. 52100, 80CrV2, 5160, O-1, L6.

Yes, 15n20 is alloyed, but it is alloyed with nickel, which does little for depth of hardening, which essentially means that it is a tougher and cleaner 1075. The 26C3 is borderline but should be able to handle the #50. There is a lot of advice about there about saving money and just using #50 on all of them, but there is no advantage to this unless you feel an increase in warped or cracked blades as advantageous. by the time you end up redoing several blades due to warping, cracking, or under-hardening, you could have paid for a bucket of AAA and #50.

I normally advise people to buy in 5 gallon quantities for the very reason you suggest. Proper quenching involves agitation and movement of fresh, cooler, oil over the part, less than several gallons rarely will allow this unless, you are doing only folder blades or minatures.
 
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BobbyD

Well-Known Member
Thanks Kevin that is very helpful. I won’t be able to get two five gal containers but I will get both. I have read several that use #50 for most of those steels..
 

Kevin R. Cashen

Super Moderator
You are very welcome. Oh, and yes I use my HT oven to temper. Very precise holds on temperature are even more important in tempering than in other heat treatment operations. For example, on W2 you can vary in a range of 50°F when hardening and still be successful, but as little as 20°F in tempering could easily cost you a Rockwell point.
 

Matt Kirby

Active Member
This is a timely thread, I just received a 5 gallon bucket of each this afternoon! I wish that the same oil was recommended for both of the materials that I'm currently using (1084 and 80CrV2) but I decided it wasn't worth the mental turmoil any longer and just bought both as Kevin has recommended so often. Now I can do my own experimenting between the two and in all honestly it's a cheap investment with all things considered.
 

Kevin R. Cashen

Super Moderator
Properly maintained, those oils can last you for years, for the advantages in producing quality blades and the shortest learning curve, it is one of the biggest bangs for your buck you can get as a knifemaker. There has been a lot of resistance over the years to this advice, but not a single maker that actually took the advice has ever looked back, once they have used a proper quench oil matched to the steel, they fully understand; it is like night and day.

Oh, and the proper maintenance is keeping the oil clean and not overheating it, and NEVER burning it. Keep it covered when not in use, solid particles tend to settle to the bottom but moisture is the worst enemy of a quench oil. Larger quantities are better because if the oil frequently heats to over 160°F it will start to break down, and if you flash it on fire it will be trashed on short order. I always warn people to never edge quench in a quench oil, but especially #50, as it really can ruin the oil. If folks need to edge quench, just get some canola oil and ruin it instead. Or better yet, abandon edge quenching as it really is counter productive to most quenching principles. For differentially hardened blades, clay them up and properly quench them, full submersion in a good quench oil, the clay will not bother the oil much and will simply gather in the bottom of the tank for later removal.
 
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BobbyD

Well-Known Member
Where can I find good read about quenching oils? When I say good I mean One of those kind for dummies lol.
If it takes a hour or hour and a half for your HT oven to cool down temperatures does that cause to much stress on the blade waiting that long?
 

Kevin R. Cashen

Super Moderator
Where can I find good read about quenching oils? When I say good I mean One of those kind for dummies lol.
If it takes a hour or hour and a half for your HT oven to cool down temperatures does that cause to much stress on the blade waiting that long?
A great primer that I often recommend, and have used it as a textbook in classes that I have taught, is "Metallurgy Fundamentals" by Daniel Brandt. This book is about high school level in explaining things, and once read you will be able to move onto about any average metallurgy text. After that there are things like the ASM Heat Treater's Guide, and my personal favorite - "Quenching and Martempering" by ASM. Also if you go to quenchant suppliers sites they will often have some of the best information on using quenchants, sites such as Houghton International, and Heatbath Corporation both have lots of information on quenching.
 
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C. Killgore

Well-Known Member
That Metallurgy Fundamentals book is a great read. I picked it up years ago from Kevin's recommendation list and it really is a great primer. I've looked for the Quenching and Martempering book several times over the years and never found a single copy :(
 

BobbyD

Well-Known Member
Yes Larry’s article you linked was a good read. Helped me to appreciate what happens during the quench and which oil to use. Also NJSB in its suggested HT suggests which oil to use (#50 or AAA) while another site I buy steel from only mentions “Quench in oil”. Thanks for your helpful replie.
 
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