Heat Treating PSA

[gscreely]

Many of you use or have used Peter's heat treat, and if you are like me you want to send them in as large a batch as you can of the same steel. I can never keep straight what steel can be treated in the same batch, and Peters (for some odd reason) doesn't put it on their site. I recently called and they gave me this chart, and I think it is super helpful. I figured it may have some value to others.

 

[jdm61]

Good list for the higher temp stuff. Peters saved me a nice bit of money by austenizing a batch that had AEB-L and 3V blades together, They do not change extra if they various blades reuqire different tempering regimens. With that said, there are a lot of steels that I would not harden at 1575 on that list.

 

[samuraistuart]

I had a hunch they hardened my wife's White 2 kitchen knife 100° harder than they should have (back before I had HT oven and good quench oil). Won't keep an edge worth spit, and is by FAR the worst performing knife we have. (1095, O7, Blue 2, AEBL) Most of the steels on the oil quenching column should be at 1475°F instead.

Got to thinking about this more, some of the carbon and low alloy steels Brad receives are/might be heavily spheroidized. In that case, the short soak at 1475 may not cut it. 1575 helps to put that carbon in solution easier, but at the expense of retained austenite, larger carbides, and slightly lower RC values post quench. Some 52100 being a good example of that.

 

[gscreely]

Good list for the higher temp stuff. Peters saved me a nice bit of money by austenizing a batch that had AEB-L and 3V blades together, They do not change extra if they various blades reuqire different tempering regimens. With that said, there are a lot of steels that I would not harden at 1575 on that list.

They actually do charge extra for different blades steels, or at least they say they do. I sent in about 150 blades with steels on all three of those lists and they did not charge me a separate fee for each type with that size order. If you call up and ask them they will tell you each steel group is another $120 charge, or whatever their current rate is. If you just sent in 6 blades in each group the way the price is listed that would be 3 separate charges, but I know they do make exceptions and give breaks on that sometimes.

 

[P.Brewster]

Brad receives are/might be heavily spheroidized. In that case, the short soak at 1475 may not cut it. 1575 helps to put that carbon in solution easier, but at the expense of retained austenite, larger carbides, and slightly lower RC values post quench. Some 52100 being a good example of that.

I asked Brad about this specifically - he said they do one 1575°F soak - no normalizing unless requested. Brad feels that the cryo remedies the RA and other issues you mentioned; that the end result is the same.

 

[samuraistuart]

Good call Patrick. I forgot they cryo everything. AFAIK, carbide size is going to be larger at 1575/cryo than 1475/no cryo, but indeed RA is dealt with as well as ability to achieve 66+ with their cryo set up. All I know...the White2 they did for me....edge retention is atrocious. Everything else they have done for me, CPM M4 and AEBL has been excellent. I heard they were hardening 1095 at 1575°F a few years back, and knew instantly that is what they used on White 2 (same heat treat), figured that had to play a decent role in poor performance on that utility knife.

Correction: carbide size and volume goes DOWN the higher the temperature during austenitizing. Hence the importance of properly setting carbide size during normalizing. Thank you Me2 (local metallurgist!)

 

[jdm61]

i was charged for one batch with the AEB-L and 3v blades, $100 MOL back then.

They actually do charge extra for different blades steels, or at least they say they do. I sent in about 150 blades with steels on all three of those lists and they did not charge me a separate fee for each type with that size order. If you call up and ask them they will tell you each steel group is another $120 charge, or whatever their current rate is. If you just sent in 6 blades in each group the way the price is listed that would be 3 separate charges, but I know they do make exceptions and give breaks on that sometimes.

 

[jdm61]

Could "slow" quench from that temp with white steel also be a culprit?

Good call Patrick. I forgot they cryo everything. AFAIK, carbide size is going to be larger at 1575/cryo than 1475/no cryo, but indeed RA is dealt with as well as ability to achieve 66+ with their cryo set up. All I know...the White2 they did for me....edge retention is atrocious. Everything else they have done for me, CPM M4 and AEBL has been excellent. I heard they were hardening 1095 at 1575°F a few years back, and knew instantly that is what they used on White 2 (same heat treat), figured that had to play a decent role in poor performance on that utility knife.

 

[samuraistuart]

JDM, that is another variable to consider, for sure. I'm fairly certain they used Parks 50, so I sorta threw that out the window as a cause for the poor performance. Also my edge was .030", plenty thin enough for a shallow hardening steel. Who knows, in all reality. And just to be clear, I am not disappointed at all with Peter's and their service. It would also be nice if they could offer normalizing and cycling, and then lower the hardening temp, but the $$$ would be northward bound. They really have a lot going on in their heat treat shop. Just saw the video of the tour Brad gave. Impressive. That's a lot to keep track of.

 

[jdm61]

Would they charge you the full $100-120 for normalizing? if you were dong a "full' batch of 20 and then some at the low per unit price, that would arguably be worth the money. Same thing for the "double quench" that Hoss suggests for AEB-L

JDM, that is another variable to consider, for sure. I'm fairly certain they used Parks 50, so I sorta threw that out the window as a cause for the poor performance. Also my edge was .030", plenty thin enough for a shallow hardening steel. Who knows, in all reality. And just to be clear, I am not disappointed at all with Peter's and their service. It would also be nice if they could offer normalizing and cycling, and then lower the hardening temp, but the $$$ would be northward bound. They really have a lot going on in their heat treat shop. Just saw the video of the tour Brad gave. Impressive. That's a lot to keep track of.

 

[samuraistuart]

The way I see it, if they're charging $30 to simply austenitize one knife, then I would think they would want to raise the price to normalize, cycle, THEN austenitize that same one blade. Same thing with 20, or 100 knives. One normalizing, three cycles....that's 4 times the amount of time of compared to just hardening. Plus the furnace is running 4x more.

If I was wanting top performance HT on these carbon and low alloy steels, 1575+cryo is not it.

 

[gscreely]

i was charged for one batch with the AEB-L and 3v blades, $100 MOL back then.

I just did a batch of 37 blades of one batch, and 2 of another. They charge $27 each for the 2 extras. I think they have more recently really hold the line on this, but look at that chart and be aware when you send stuff in.