Aldo's Steel HT and Spheroidized Steel

I

Ian Fifelski

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Oct 4, 2017
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I have heard that Aldo's steel is spheroidized and the ht is different. What is different? I've seen that it needs to be reverse hted (whatever that means) and elsewhere ive heard it NEEDS to be normalized. Whats up with it?

thanks
 
Aldos 52100 was spheroidized and needed normalizing cycles. My understanding is that he has corrected that issue and normalizing is no longer necessary, but never a bad idea. I don't know what reverse heat treating is.
 
There was also some 1084 that was so heavily spheroidized that it required normalization, but I think it was limited to a particular batch.
 
The links in the stickies are missing. Normalizing is heating above ac3, around 1550f for many of the steels we use. Higher temps break up the course spheroid quicker, so many use 1650f, but this results in grain growth, so after breaking up the spheroids,we thermal cycle using 1550f, 1450f, and even 1400f. Soak 10min at each temp, and cool to black, about 900f. The steel will become magnetic again when cool enough. Each cycle below ac3 results in new grains forming within the boundaries of the old grains, creating smaller and smaller grain size. These cycles result in an even distribution of alloys, carbides, and a small, even grain size. The steel is in ideal condition to heat treat now. You can also use a sub critical anneal for 2h to create a fine spheroidize, if you need to grind or machine after the cycling. Fine spheroidizing is easier on belts and tooling than pearlite, which is what you have after the above cycles.

This is overly simplified, but gives you a basic overview of the processes and why they are done.
 
E.Carlson said:
There was also some 1084 that was so heavily spheroidized that it required normalization, but I think it was limited to a particular batch.
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There was a batch about four years ago that was course spheroidized. The 1/4” stock was the worst. For some batches, a longer soak was all it took to heat treat, others such as the 52100, the one batch of 1084, and a batch of 80crv2, you had to normalize and thermal cycle, or the steel wouldn’t harden.
 
I talked to their customer service very recently and they recommended two normalizing heats at 1650, cool to black, heat to 1500 and quench in Fast oil, this was for steel that was 3/16 thick without any bevels ground yet.
 
I think it would be worth saying those batches are not "screwed up".
The coarse spheroidizing comes from a costly heat treat regimen, and has the effect of making the steel into its best arrangment to be filed/machined. It is as soft as it can be (industry would love it). You will save belts, files and drillbits. The best for stock removal.
In order to put all the carbon back into play for hardening, a simple normalization, followed by grain refining is not a big deal.
I understand that someone might prefer a ready to heat treat configuration, even if it would mean a less easier steel to machine, but a spheroidized steel is not a bad steel, in my own opinion.
 
I ordered mine in the last 2 months and that's all I did. It hardens just fine. My heat treatment is as simple as you can get.
 
Runthemall said:
So, my 1/8 inch 1084 doesn’t need any special treatment? Just heat and quench?
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A thermal cycle isn't a bad idea since you can't be sure of the state of the steel. That being said, you can probably get away without it (I have with 1/8 1084). If you have problems, you know what the likely culprit is.
 
Runthemall said:
So, my 1/8 inch 1084 doesn’t need any special treatment? Just heat and quench?
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If you get Rc66/67 out of quench, you are likely fine. If it doesn’t harden, or you come out below Rc64/65, you have an obvious point to start experimenting from.
 
Willie71 said:
If you get Rc66/67 out of quench, you are likely fine. If it doesn’t harden, or you come out below Rc64/65, you have an obvious point to start experimenting from.
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This is why a hardness tester is quickly getting higher on my wish list.
 
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E.Carlson said:
This is why a hardness tester is quickly getting higher on my whish list.
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The people with the least sophisticated equipment should be the ones following the normalization/thermal cycling procedures to get the best results, but it seems that the opposite is true in most cases. This isn’t directed at you, just a comment in additi9n to your post. Same with recycled steel. Those with the equipment to test it properly are less likely to use recycled steel than those with no way to test their results.

I got my hardness tester right after my first failed blade.
 
Willie71 said:
The people with the least sophisticated equipment should be the ones following the normalization/thermal cycling procedures to get the best results, but it seems that the opposite is true in most cases. This isn’t directed at you, just a comment in additi9n to your post. Same with recycled steel. Those with the equipment to test it properly are less likely to use recycled steel than those with no way to test their results.

I got my hardness tester right after my first failed blade.
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I agree. Since I obtained my heat treating oven, I've been using pretty much only 15N20 from Chuck at AKS and using your recipe. I feel like I'm in a good spot relying on Chucks steel and your testing. I'd feel better about expanding into other various steels if I had the ability to do my own testing and experimenting.
Since we are on the topic, a have the chance to pick up a pawnshop HR 150-A model Rockwell tester in the 500 dollar range. Doubt it has blocks or a manual. Think it's worth the gamble?
 
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