52100 and 80CRV help

Outdoor Gear Dad

Outdoor Gear Dad

Joined
Jun 1, 2019
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I am experiencing some thing with my last batch of steel that I have never experienced before. I’m at a complete loss and I’m wondering if I potentially got the wrong steel. Got them from NJSB.

I ordered 1/8 52100 and 1/8 80CRV2. Cut blanks from both of them, drilled, surface grinded, and prepped for heat treat.

I did three normalization processes for both steels:

Cycle 1: 1650 degrees hold for 15
Cycle 2: 1500 degrees hold for 15
Cycle 3: 1350 hold for 15 minutes.

On the 52100 I did an austenizing hold at 1525 degrees for 15 minutes, followed by a fast oil quench in parks 50.

For the 80CRV2 I did 1525 for 10 minutes followed by fast oil quench in parks 50.

I tempered both at 400° for two hours twice.

Both these steels are reading in the low 50s. I thought maybe something was off so I annealed both steals and tried again. But this time I intentionally lowered the tempering temperature to 300°. I am still in the low 50s.

Here is what I am using:

Even heat KH414 with rampmaster controller
I use a tempering oven that is connected to a PID Controller and a 4” thermocouple.
And I use an Ames portable Rockwell tester (PHR-1) that I am also checking against calibrated blocks and is reading accurate.

Please help.
 
+1 on the previous post. My Evenheat kiln reads low by 60 degrees.
You're cooling to black between the cycles?
There may still be decarb on the surface causing a false low reading.
The other thing that I can think of is the quenchant might be too fast. I know that some people quench 52100 in fast oil, I have better results in medium speed oil.
You could also try the protocol advocated by Larrin Thomas, our resident metallurgist.
https://knifesteelnerds.com/2019/05/13/how-to-heat-treat-52100/
 
That's close to the exact recipe that I use for NJSB's 52100 except I final temper at 340 and SS foil thermal cycles (not during austenization). 63-64 out of the quench (after removing light decarb) and 60-61 after temper.

Check that your removing Decarb, verify kiln temp, and maybe lower your temper temp. That's where I'd start.
 
Grind into the samples more, you did a lot of cycling (and then annealing), which is all time for decarburization.
 
Outdoor Gear Dad said:
I am experiencing some thing with my last batch of steel that I have never experienced before. I’m at a complete loss and I’m wondering if I potentially got the wrong steel. Got them from NJSB.

I ordered 1/8 52100 and 1/8 80CRV2. Cut blanks from both of them, drilled, surface grinded, and prepped for heat treat.

I did three normalization processes for both steels:

Cycle 1: 1650 degrees hold for 15
Cycle 2: 1500 degrees hold for 15
Cycle 3: 1350 hold for 15 minutes.

On the 52100 I did an austenizing hold at 1525 degrees for 15 minutes, followed by a fast oil quench in parks 50.

For the 80CRV2 I did 1525 for 10 minutes followed by fast oil quench in parks 50.

I tempered both at 400° for two hours twice.

Both these steels are reading in the low 50s. I thought maybe something was off so I annealed both steals and tried again. But this time I intentionally lowered the tempering temperature to 300°. I am still in the low 50s.

Here is what I am using:

Even heat KH414 with rampmaster controller
I use a tempering oven that is connected to a PID Controller and a 4” thermocouple.
And I use an Ames portable Rockwell tester (PHR-1) that I am also checking against calibrated blocks and is reading accurate.

Please help.
Click to expand...
Why first you don t try to HT samples without normalization processes ? 45 minutes on 1500 F and half steel is gone probably .As other advice you , you need to protect steel when you do such long process........
 
Natlek said:
Why first you don t try to HT samples without normalization processes ? 45 minutes on 1500 F and half steel is gone probably .As other advice you , you need to protect steel when you do such long process........
Click to expand...

Because you have to normalize most all of NJSBs carbon steels. And even then some times it still will not harden. In fact just today I was heat treating 3 W2 (NJSB steel) blades for a customer and no mater what I tried thy would not get over 41rc.

So yeah it could be decarb but it’s not going to be crazy deep. If you can’t find hard steel then most likely your steel is bad. Contact them and have them replace it.
 
Last edited:
I had a similar problem with some 80CrV2. It ended up being decarb like others have suggested. I even thermo-cycled in SS foil.
 
Larrin said:
Grind into the samples more, you did a lot of cycling (and then annealing), which is all time for decarburization.
Click to expand...
how would I know if I removed all the Decarb? There is obvious visible Decarb which I removed on a surface grinder with a 120 grit belt. Then threw on a trizact belt just to make the surface nice and smooth. Made sure it was cool while doing the surface grinding.
 
imill3567 said:
I personally would find a way to verify my kiln and tempering oven temps before anything else.
Click to expand...
What do y’all use to check your kiln temp? My kiln is less than a year old, but would love to use this recommendation and weigh that out. Is there something on Amazon I could get that won’t break the bank?
 
Decarb will throw a dull straight spark compared to a bright complex spark from clean hardened and tempered steel. It’s harder to tell when grinding by hand as apposed to using a surface grinder.

Hardened and tempered steel will etch darker than the decarb layer.

Hoss
 
You can see a difference in the steel as well. We grind tiny spots with a small contact wheel to get through the decarb. I would recommend to grind a .02 deep spot on the tang does not have to be real big. If there is decarb you will see a transition in color and grit finish. If it is the steel not hardening you can try another trick that has worked for me with their steels some times. Heat the blades up to 1900° at if you where going to forge them but let them air cool. Then do your normalizing and thermo cycling. If you don’t want to go through all the grain refining steps to see if it worked you can just normalize at 1600-1650. Then do your normal heat and quench process. Also I have found that sometimes parks is not fast enough at room temp to harden a few difficult alloys so I heat to it to 100°.
 
JTknives said:
You can see a difference in the steel as well. We grind tiny spots with a small contact wheel to get through the decarb. I would recommend to grind a .02 deep spot on the tang does not have to be real big. If there is decarb you will see a transition in color and grit finish. If it is the steel not hardening you can try another trick that has worked for me with their steels some times. Heat the blades up to 1900° at if you where going to forge them but let them air cool. Then do your normalizing and thermo cycling. If you don’t want to go through all the grain refining steps to see if it worked you can just normalize at 1600-1650. Then do your normal heat and quench process. Also I have found that sometimes parks is not fast enough at room temp to harden a few difficult alloys so I heat to it to 100°.
Click to expand...
Wouldn’t doing a small spot make the surface not flat? I’m thinking if I did a small spot, how would I be able to lay that small spot on the tester to get an accurate reading?
 
Outdoor Gear Dad said:
What do y’all use to check your kiln temp? My kiln is less than a year old, but would love to use this recommendation and weigh that out. Is there something on Amazon I could get that won’t break the bank?
Click to expand...
You would need a high temp k-type thermocouple with the ceramic sheath and the handheld thermometer to read the thermocouple. Probably about $70 for a cheap set up and I’m sure the sky is the limit on high end laboratory stuff. Only problem with the cheap ones if the accuracy is +\- 2% that’s going to be ballpark 30deg for your carbon steel heat treat temps. It would still let you know if it’s way off though.
 
Outdoor Gear Dad said:
Wouldn’t doing a small spot make the surface not flat? I’m thinking if I did a small spot, how would I be able to lay that small spot on the tester to get an accurate reading?
Click to expand...
Correct, needs to be surfaced flat +120 grit.

https://www.buehler.com/best-practices-rockwell-hardness-testing.php

"concave surfaces will provide higher material support due to the curvature towards the indenter and result in apparently harder material due to production of a shallower indent."
 
Outdoor Gear Dad said:
Wouldn’t doing a small spot make the surface not flat? I’m thinking if I did a small spot, how would I be able to lay that small spot on the tester to get an accurate reading?
Click to expand...
I’m not sure how your hardness tester is set up but we hardness test down in the bottom of the ground spot. In all my tests it has not affected the hardness readings at all. Our contact wheel is just over 3/4” and I use the edge and do a short hallow grind of sorts on the tang.
 
Outdoor Gear Dad said:
What do y’all use to check your kiln temp? My kiln is less than a year old, but would love to use this recommendation and weigh that out. Is there something on Amazon I could get that won’t break the bank?
Click to expand...
A cheap sanity might be to melt some salt.
 
I got my second thermocouple from Auber Instruments. I drilled a hole in the Kiln door to place this TC closer to where the blades sit in the kiln. I then tested a bunch of coupons and saw that when I went off this second TC my results were better and mirrored the typical published protocol numbers. The Evenheat TC measured low an average of 60 degrees.
Here's what I use:
https://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=39
https://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=14
 
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