Benchmade Magnacut Heat Treatment

[Karl H]

Benchmade released an article explaning the basis for their selected Mangacut heat treatment specification (which can be found here). In the article, they give an article that compares the properties of the different Magnacut properties that they tested, which is shown below.

https://imgur.com/a/EF1uZ8K

The thing that really stands out to me about this chart is that they corrosion resistance of the chosen heat treatment appears to be markedly worse than Option 3 (62.5 HRC). The only tests where the chosen heat treatment outperforms the others is in "chipping" and "impact". Frankly, it doesn't seem like the gains in toughness are worth the reduction in other performance catagories.

The Crucible Magnacut Datasheet recommends the following heat treatment:

Austenitize 2050°F (1120°C). Quench to below 125°F (50°C). Double temper at 350°F (175°C) 2 hrs. minimum each temper. Cool to hand warm between tempers. A freeze treatment may be added after the quench. Aim hardness: 60-63 HRC.

https://imgur.com/a/vG8Bjbu

Larrin Thomas provides more detail on the testing he did of various heat Magnacut treatments. Most notably, he provides a chart that shows an increase in toughness of 2 ft-lbs (12.5% increase) for the 60.5 HRC heat treatment over the 62.5 HRC heat treatment.

https://imgur.com/a/VGhOcjR

My personal opinion is that the gain in toughness for Benchmade's chosen heat treatment is isngificant, given that Benchmade tends to be very conservative with how they grind and sharpen their knives. As far as I can tell, they seem to be using the same grinds and sharpening angles for their Magnacut knives as they do for their PM stainless steels (S30v, 20cv, S90v, etc.) knives, even though Magnacut has better toughness even at the top end of its potential hardness range.

https://imgur.com/a/XlEyAvx

 

[Delta-v]

The problem with that graph is that there are no numbers or units. If you focus on the corrosion axis, it does show that Benchmade's chosen heat treatment is second best after the 63HRC. But how much of a real difference is it? Note that the worst performer for corrosion, the green dash line all the way near the center, is S45VN, a steel known for great corrosion resistance. So it looks like the spectrum for corrosion resistance on this axis ranges from the spectacular to the merely great, and Benchmade opted for something around excellent.

Anything above 60HRC that was done properly is fine with me. High hardness can be achieved with bad heat treatment, too.

 

[Delta-v]

I'll also mention that Larrin and Crucible both recommend the 2050/350 heat treatment. If you look at the data sheet above in the vacuum furnace section, you'll see that protocol lands at 60.5. So it looks like Benchmade is quite possibly using the recommended heat treatment without the cryo option.

 

[Texaspoff]

I found my 940-03 to be poorly treated. To soft IMO as the edge would roll, which isn't all that bad, but overall it wouldn't hold an edge even as well as their S30 and that's saying something. From their chart it seems 62.5 provides more even attributes and qualities.

IMO Benchmade is running their Magancut with the heat treat that allows them the easiest production with the steel. This keeps tooling from wearing out as fast as say s90. Benchmade is just getting on the magancut train trying to get their piece of the pie.
As with most steels, there are very few production companies that are truly heat treating steels to get the most performance out of them. It's more about quantity than quality.

After all the steels I have used, sharpened and played around with, at this point, I'm more about the design that the steel, at least in certain categories. In other words, I'm not spending the extra money on production s90 version of a knife compared to an s30 version of it. It simply isn't worth it IMO.

My last two Bugouts, a standard s30 model with AWT scales, and an s90 model with G-10 scales both suffered from corrosion issues, and edge holding between the two were almost exactly the same. At the same time I have had D2 Elementums exposed to the same conditions, that suffered had zero corrosion.

Now I just look for knife designs that I like and that suit my needs, that has a decent steel. I certainly don't seek out certain steels on a specific model any more. I chased that dragons trail too many times. YMMV





TXPO

 

[Larrin]

I'll also mention that Larrin and Crucible both recommend the 2050/350 heat treatment. If you look at the data sheet above in the vacuum furnace section, you'll see that protocol lands at 60.5. So it looks like Benchmade is quite possibly using the recommended heat treatment without the cryo option.

I made the Crucible datasheet so those are not really independent sources. There are a few things in Benchmade's charts that don't make sense to me but I can't see the raw data or test methods so hard to argue. There are properties that should be correlated that aren't so I couldn't guess at what heat treatments led to those results.

 

[Delta-v]

I made the Crucible datasheet so those are not really independent sources. There are a few things in Benchmade's charts that don't make sense to me but I can't see the raw data or test methods so hard to argue. There are properties that should be correlated that aren't so I couldn't guess at what heat treatments led to those results.

Thanks for clarifying, Dr. Thomas. I had suspected you probably had more than a little to do with that datasheet. I'll agree that the chart didn't really make sense to me either. I've learned to take such charts with a grain of salt if I can't see the hard data from which it was created.

 

[Maximumbob54]

I'd prefer they ran everything a little harder to keep an edge longer. My number one use by a wide margin with a folder is slicing and cutting so if that isn't the primary reasoning behind the heat treatment it makes me question if I really want the knife. It's the same thing for some 3V folders I bought a while back. Do I really need that kind of toughness in a folder when S35VN should hold an edge much better? It just feels like Magnacut not run hard in a folder is a bit of a waste. Makes me curious why not just LC200N or other super stainless option. Now maybe in a large fixed blade you could run it to the softer side for some fixed blade toughness shenanigans.