How close to "full" hardness from quench w/ canola and 1084?

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Pete84

Pete84

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Hey, all.

I know that 1084 with a quench in canola is the generally prescribed HT recipe for newbies/those w/o HT oven.

I'm curious to find out about how close to the full hardness one can get straight from a canola quench, assuming the steel was at the proper austenitizing temperature, canola was heated to 130, proper agitation -- essentially, if the HT were as perfect as is could be from a primitive setup, how close to the full hardness of 65 (HT'ers guide states 65 is full hard, although their formulation doesn't have the manganese Aldo's does) would one be able to get vs. using a HT oven and say Parks or other formulated quench oil? A point or two off, or a larger gap than that? Or is the hardness roughly the same but the structure is a larger percentage Ms/lower RA likely with proper quench oil because of the faster cooling rate?

Also, using Aldo's 1084, does anyone have an approximate table of tempering temps and corresponding HRC values? I've seen several -- some with 1080, some 1084, and even just the ones pertaining to 1084 varied quite a bit.

Naturally a Rockwell tester would be ideal, but I can't seem to find any machine shops or commercial heat treaters in the area who have one.

Thanks!
 
Frankly, you are going to get a lot of answers, but I bet that you aren't going to be able to tell the difference. when you are spending 50 bucks a knife in steel alone, then engineered quench oil starts to become practical, but for 1084, I don't think it will make a big enough difference to be worth the cost of parks 50 or the like.

Disclaimer: I am not an expert. I am pretty much a newbie, but I have had 1084 quenched in canola and it performs a lot better than I would have assumed for a steel which costs less than the sandpaper and pins it takes to finish it, or at least close. just my opinion, but if you can notice the difference, it might be time for a steel upgrade.

Second disclaimer: if anyone contradicts me, disregard this post ;)
 
thegeek574 said:
Frankly, you are going to get a lot of answers, but I bet that you aren't going to be able to tell the difference. when you are spending 50 bucks a knife in steel alone, then engineered quench oil starts to become practical, but for 1084, I don't think it will make a big enough difference to be worth the cost of parks 50 or the like.

Disclaimer: I am not an expert. I am pretty much a newbie, but I have had 1084 quenched in canola and it performs a lot better than I would have assumed for a steel which costs less than the sandpaper and pins it takes to finish it, or at least close. just my opinion, but if you can notice the difference, it might be time for a steel upgrade.

Second disclaimer: if anyone contradicts me, disregard this post ;)
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Thanks for the reply, geek. I think you may have missed my point though. It isn't about noticing a difference. It's about making the best quality blade I can with the equipment at my disposal and understanding why it is better. If things like this aren't important, then investing in a heat treat oven and commercial quenchants becomes pointless. By that standard, we should treat 1095, 1084, w2, 1075 and most other simple carbon steel the same because they will all harden just above non magnetic and differences wouldn't be hugely noticeable, for the most part. And yet, each of those steels is a little different and reacts differently than the others with a change in process here, tweak there. Those differences are why it becomes, in my opinion, so important to understand fully the effects of what we are doing to them and how the variables in play cause steel to react and transform internally.

I hope my response doesn't seem rude, as that is not my intent. I'm simply trying to illustrate why I think understanding the finer points of whatever treatment we chose to apply is so vital, even when the equipment is semi primitive. I think that understanding is what helps one to evolve as a bladesmith. :)
 
Are you talking about the "full hardness" that will be "tempered down"?
 
BMK said:
The quest for "full hardness" only to temper it back down is a conundrum for me.
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Martensite is the phase (microstructure) that makes a good hard durable edge, but in it's initial state is full of stress and brittle, tempering relieves just a little of that stress which makes it less likely to chip or break. You want to convert all of your steel to Austentite when you heat it, then you want to quench quickly enough that you transform all of that Austentite to Martensite without losing any to Pearlite. In stainless steels things are a little more complicated because the other stuff in the mix inhibits complete conversion until you hit cryogenic temperatures, but same basic principles, then since a full hard (completely converted to Martensite) blade is brittle from the stresses involved, you temper it to relax the structure just a little

-Page
 
Thank you. I am sure it all makes perfect sense...just not to me. If there is a difference between hardness and full hardness, it stands to reason that the differential would be further mitigated during the tempering cycle.

sunshadow said:
Martensite is the phase (microstructure) that makes a good hard durable edge, but in it's initial state is full of stress and brittle, tempering relieves just a little of that stress which makes it less likely to chip or break. You want to convert all of your steel to Austentite when you heat it, then you want to quench quickly enough that you transform all of that Austentite to Martensite without losing any to Pearlite. In stainless steels things are a little more complicated because the other stuff in the mix inhibits complete conversion until you hit cryogenic temperatures, but same basic principles, then since a full hard (completely converted to Martensite) blade is brittle from the stresses involved, you temper it to relax the structure just a little

-Page
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So, Page, if I understand you correctly...

Assuming proper austenitizing, the faster you can safely quench, the more of that As converts to Ms, resulting in full hardness? And Stacy said full hardness can be achieved with canola, so it is capable of quenching fast enough.

I guess that begs another question... On 1084 what, if any, benefit would be derived from using a commercial quench oil? Evidently it doesn't yield Higher initial hardness on a simple steel like 1084, so does it somehow help with more uniform formation of Ms, better stability with less potential to warp, or do those oils like Parks only really benefit some of the higher end/more picky steels that need a faster quench?

Not trying for another Parks vs Canola vs Motor oil debate... Just trying to understand what's taking place inside the steel structure that might make a commercial quench oil beneficial in this particular scenario.
 
BMK said:
Thank you. I am sure it all makes perfect sense...just not to me. If there is a difference between hardness and full hardness, it stands to reason that the differential would be further mitigated during the tempering cycle.
Click to expand...

Lets see if I can explain it the way I understand it. In order to get the best performance from the steel you must bring it to full hardness and then temper it back down to a useable hardness. If the steel isn't properly heated and quenched properly to do this structure change completely the steel will never reach its full potential.

The way that I am wrapping my head around it is I look at it like hand sanding a blade for a 800g satin finish. Yes I could just sand up to 800g and leave it, but I get better and more consistent results if I sand it out or 1500 or better and then go back to the 800g.
 
Pete84 said:
So, Page, if I understand you correctly...

Assuming proper austenitizing, the faster you can safely quench, the more of that As converts to Ms, resulting in full hardness? And Stacy said full hardness can be achieved with canola, so it is capable of quenching fast enough.

I guess that begs another question... On 1084 what, if any, benefit would be derived from using a commercial quench oil? Evidently it doesn't yield Higher initial hardness on a simple steel like 1084, so does it somehow help with more uniform formation of Ms, better stability with less potential to warp, or do those oils like Parks only really benefit some of the higher end/more picky steels that need a faster quench?

Not trying for another Parks vs Canola vs Motor oil debate... Just trying to understand what's taking place inside the steel structure that might make a commercial quench oil beneficial in this particular scenario.
Click to expand...

I know this question wasn't directed at me, and I am still trying to understand the principals of HTing, but the way I see it is that the engineered quench oil are designed to preform the same way every time where canola oil doesn't have this, one brand of canola oil could preform different than the next or even one batch to the next from the same producer. Like thegeek I am still learning so I could be way off base:o
 
Theoretically, the blade quench in canola would be superior to the one quenched in the engineered fluid, because of the more uniform cooling mechanism… It would be 101% vs. 100%. :)

The only advantage to using an engineered fluid would be to cut cost in high volume mass production, which really has nothing to do with performance..
 
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Thanks guys. I think I'm starting to see the whole picture a bit better now. I hope I'm not coming across as l the idiot trying to force a square peg through a round hole." I just find the metallurgical aspects of being a bladesmith absolutely fascinating and between reading and the forum, I'm sponging in as much information and as many viewpoints as I can manage. I appreciate you all humoring me and taking the time to share your collective knowledge.

On another note, I think it may be time for me to find a school with a good metallurgy program. Seriously.
 
unky_gumbi said:
I know this question wasn't directed at me, and I am still trying to understand the principals of HTing, but the way I see it is that the engineered quench oil are designed to preform the same way every time where canola oil doesn't have this, one brand of canola oil could preform different than the next or even one batch to the next from the same producer. Like thegeek I am still learning so I could be way off base:o
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There have been a number of studies on vegetable oil quenchants including canola. In every study I've read the oils used were aquired randomly from a local grocery store and showed identical results.
 
i have been using canola oil to quench my blades for years (the steel is1075 though) and i get my blades up around 63-65 rc. i have used a mix of motor oil and transmission fluid before with similar results when i was out of canola oil but i think i'm going to stick with canola oil from now on.

i heat treated 3 knives last week and although i have yet to get them rc tested, i would say they are within the range i want but i plan on testing them just to make sure.
 
To add to the question if I may. If quenching 1080/1084 in Parks 50 I assume I will get full transformation from As to Ms. But, does the faster quench w/ Parks 50 add stress or a higher risk of warp? I know Parks 50 is faster than needed for 1080/1084....My question assumes proper heat control, normalizing, and uniform grind, sanding etc? Not trying to add/start a Canola/Parks debate.
All I have is Parks 50 and no canola.....w/40' of 1080 and 1084......

Excellent Post/question Pete... I too love the metallurgical art/science of bladesmithing...
 
The Parks is engineered to quench extremely quickly to MS then cool slowly through to room temp which should make it less likely to crack as your highest internal stress and possibility of crack formation is once things start to stiffen up

-Page
 
Tai Goo said:
There have been a number of studies on vegetable oil quenchants including canola. In every study I've read the oils used were aquired randomly from a local grocery store and showed identical results.
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We should get the references we discussed in past thread here on Canola in the stickies. I think we know more about Canola oil used as a quenchent then Parks 50. Trying to find out all the details and studies on Parks 50 has proven to be not so easy.

If anyone has studies and research on the use of Parks 50 please post the information so we can add to the database :)
 
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