How to Heat Treat CPM-154

[Larrin]

I did a range of heat treating experiments with CPM-154 to try to find optimal combinations for good toughness and overall properties. It turns out the datasheet has some problems, but I have an alternative for better information. I also did a comparison with a previous toughness measurement which does not line up. https://knifesteelnerds.com/2020/03/16/how-to-heat-treat-cpm-154-toughness-experiments/

 

[Willie71]

I have never used this steel, other than heat treating it for a customer once. I found the process of trying to figure out the oddball result the most interesting part.

 

[Larrin]

I have never used this steel, other than heat treating it for a customer once. I found the process of trying to figure out the oddball result the most interesting part.

I thought presenting the discrepancy would be more fruitful then sweeping it under the rug. I'm glad someone got something out of it.

 

[godogs57]

I ht as follows: 1950 for 30 minutes, plate quench with two1" thick aluminum plates, temper 3x at 400, 2 hours. I get 60.5-61.0 Rockwell.

 

[Stacy E. Apelt - Bladesmith]

Great to hear.
I have been using 1950F with a 45 minute soak, heavy quench plates clamped tightly, immediately into a dry ice bath, immediate 350F temper twice. I consistently get Rc62 and excellent toughness.

 

[Scaniaman]

Exactly how similar are CPM-154 and RWL-34, and how come there are such extreme differences in time at aust temp in the data sheets? Roughly 10 min for RWL vs 1 hour for CPM.
When I HT RWL I hold for 10 min at 1950 F, aluminium block quench, freeze at -45.5 Fahrenheit over night, temper at 347 Fahrenheit for 2 hrs. Ends up at 62-63 Hrc.

 

[Larrin]

Exactly how similar are CPM-154 and RWL-34

They are near identical.

 

[Scaniaman]

That's what I figured, thanks!
So, weird that data sheets are so different..

 

[Larrin]

That's what I figured, thanks!
So, weird that data sheets are so different..

There are different hold times possible and it also depends on what range of thickness you are developing the datasheet for. So the austenitizing time depends a lot on the person making the datasheet.

 

[NYMet]

If you compare the 154CM conventional data and the PM version the heat treat protocol is identical. The date on the PM version is after the bankruptcy so their research was closed and most of the metallurgists were gone. This looks like a classic case of someone assuming the conventional data would naturally match the PM version. In my experience, PM versions of conventional steels never heat treat quite the same.

 

[Willie71]

If you compare the 154CM conventional data and the PM version the heat treat protocol is identical. The date on the PM version is after the bankruptcy so their research was closed and most of the metallurgists were gone. This looks like a classic case of someone assuming the conventional data would naturally match the PM version. In my experience, PM versions of conventional steels never heat treat quite the same.

I had that experience with cru-wear and z-wear. 1-2 Rockwell points difference.

 

[daizee]

Awesome, Larrin, thank you. Looks like CPM-154 is still a solid all-around choice in a stainless, despite the 'adjustment' from the original single measurement. I'm also happy to see that your optimized HT is nearly exactly my protocol, so naturally I like this article.

 

[Larrin]

Awesome, Larrin, thank you. Looks like CPM-154 is still a solid all-around choice in a stainless, despite the 'adjustment' from the original single measurement. I'm also happy to see that your optimized HT is nearly exactly my protocol, so naturally I like this article.

This one ended up with a fairly standard heat treatment so I'm not surprised.