Hogue Blades - 154 CM Cryo-treated?

[Gunsnknives]

Hi All,

Does anyone have experience with the Hogue blades and their cryo-treated 154 CM steel? I'm wondering how much the cryo-treatment really does. Does it increase hardness and wear resistance?

Thanks,

 

[neuron]

It's just marketing jargon. Don't expect any difference between the performance of their 154CM and that of any other quality company (Benchmade, Emerson, etc.).

 

[jimnolimit]

cryo treatments are used to help convert more austenite to martensite. many companies use cryo treatments in their heat treat recipe, some just don't say it.

 

[Tsujigiri]

Yep, basically the idea is that martensite has a very hard crystalline structure. But it can only form if the austenite is cooled fast enough that the carbon does not have time to diffuse through the iron (If it does, a lot of other softer phases can form). So companies have various ways to rapidly cool their steel to ensure that martensite does form and therefore a stiff and strong metal results. Hogue's 154 CM shouldn't be special, though, a lot of companies know how to properly heat treat steel.

 

[Buck_110]

A finished knife(or any metal object) will also benefit from a cryogenic treatment. Stress is relieved and toughness is increased.

 

[Noctis3880]

A finished knife(or any metal object) will also benefit from a cryogenic treatment. Stress is relieved and toughness is increased.

I could be wrong what with only a basic textbook of metallurgy, but I thought Cryo was for hardness while tempering is for stress relieving and toughness?

 

[Buck_110]

I thought Cryo was for hardness while tempering is for stress relieving and toughness?

Cryogenic treatments can be employed at various stages of production. As with heat-treating, it lies in the hands of the manufacturer/maker.

After tempering, the knives are cleaned to remove discoloration, they're sharpened, polished, etc. Any stress imparted to the steel during these processes can be removed with a cryogenic treatment.

Any metal object can undergo a cryogenic treatment at any time to relieve stress.

 

[clockman]

I've read a few articles on cryogenic treatments but I've learned a lot more from some of the more knowledgeable posters here in this tread.

 

[topherO]

I've got one of Hogue's 154 cm 'cryo treated' blades and can't tell any difference in hardness, edge retention, ease of sharpening, etc from my other 154 cm blades.

 

[Ankerson]

As others have stated, it's just marketing.

 

[Gunsnknives]

Thanks guys. I am learning new things every day. Interesting to hear that the Hogue 154 CM is basically the same as everyone else's. That is good, but I was hoping for better.

Great learnings about the cryo-treatment.

Thanks again!

 

[Ankerson]

Thanks guys. I am learning new things every day. Interesting to hear that the Hogue 154 CM is basically the same as everyone else's. That is good, but I was hoping for better.

Great learnings about the cryo-treatment.

Thanks again!

154CM at 57-59 HRC is 154CM at 57-59 HRC.....

Unless you get a Master HT like Phil Wilson who does blades one at a time and can tweak them to get what he wants out of them, but that's a whole another world and thread.

 

[Phil Wilson]

Gunsknives, As stated earlier, steels that have an high alloy content may not transform completely when air quenched down to room temp. The cryo cycle will help finish the transormation to Martensite. This is most effective right after the initial quench and prior to any tempers. Left over retained austenite can transform by itself over time creating stress areas and dimension changes in the blade. It is also softer than martensite and large amounts can lower the wear resistance. Relieving stress in a blade is only possible with tempering. A cryo cycle by itself will not do much if anything to relieve stress after all the tempers cycles are done. I have found that a final temper at 20 degrees lower than the last one will help relieve any residual grinding or finishing stresses.

 

[hardheart]

Cryo increases stress in steel when the retained austenite converts to martensite. The hardening process increases stress in steel. That is pretty much the point of martensite conversion, and why steel gets hard and has more bend resistance after quenching. The temperature has to be lowered more quickly so as to freeze the elements in place, where they do not 'want' to be.

 

[Buck_110]

As others have stated, it's just marketing.

Since consumers have no way of verifying if metals were cryogenically treated, this can indeed be true.
For metals that have undergone cryogenic treatment, benefits are realized.

When a cryogenic treatment is employed to relieve stress(not during the tempering process of the heat-treatment to convert more austenite to Martensite), retained kinetic energy is reduced. This slows down the molecules and reduces stress. Since retained stress is actually retained energy(excited molecules), stress can 'spread' when metal is torqued.
Less retained energy = less molecular movement = less retained stress = increased toughness and wear-resistance.

Race car drivers(especially NASCAR) have been employing cryogenics for some time now; from brakes to pistons. Their testing and real-world experience has proven it to be beneficial.

 

[mete]

And now from a metallurgist !! Cryo is PART OF the HT and will give 1-2 HRc points hardness increase .Other than that there's much hype.

 

[Buck_110]

And now from a metallurgist !! Cryo is PART OF the HT and will give 1-2 HRc points hardness increase .Other than that there's much hype.

If a product is sent to a cryogenic facility to be stress-relieved, is only a 'part' of the heat-treat process being applied?

Some musicians have their horns(trumpets, trombones, etc.) cryogenically treated to remove stress to improve sound. Since they're brass, the goal is not to convert more austenite to Martensite; or increase the Rockwell hardness.

 

[Phil Wilson]

Buck110, not sure about cryo treatments to relieve stress in alum, titanium and cast iron ect. (NASCAR) but in a high alloy knife blade it is most effective right after the initial quench. Again to yield full conversion to martensite, a very stressed condition. Tempers will modify the crystal structure to a more relaxed state and reduce the stress and hardness and improve ductility. If the cryo cycle is not done some temper techniques can reduce the retained austenite for more martensite conversion but this is not as effective as the cryo treatment. If the cryo cycle is done after tempers and it does in fact move some retained austentite to martensite then you have some untempered martensite, which is again adding stress to the blade if left in that state. Another temper is required to modify the martensite structure. Tool steel data sheets recommend that a temper cycle always follow cryo treatment. This whole discussion on relieving stress with a cryo treatment is controversial. I recently spoke with a rifle barrel maker who uses 416 SS to make custom match barrels. He has deleted the cryo cycle and instead does multiple tempers after the final machine and finish work and claims better results. To answer the original poster and his question, a cryo cycle on 154CM is very benifical. Quenched 154CM can have as much as 30% retained austenite after the initial quench. A cryo cycle will reduce this down to around 5% as per my metallurgist mentor. The point is it has to be done in the correct sequence and just saying "cryo treated" does not mean that the steel has been improved for a knife blade. Phil

 

[Ankerson]

Buck110, not sure about cryo treatments to relieve stress in alum, titanium and cast iron ect. (NASCAR) but in a high alloy knife blade it is most effective right after the initial quench. Again to yield full conversion to martensite, a very stressed condition. Tempers will modify the crystal structure to a more relaxed state and reduce the stress and hardness and improve ductility. If the cryo cycle is not done some temper techniques can reduce the retained austenite for more martensite conversion but this is not as effective as the cryo treatment. If the cryo cycle is done after tempers and it does in fact move some retained austentite to martensite then you have some untempered martensite, which is again adding stress to the blade if left in that state. Another temper is required to modify the martensite structure. Tool steel data sheets recommend that a temper cycle always follow cryo treatment. This whole discussion on relieving stress with a cryo treatment is controversial. I recently spoke with a rifle barrel maker who uses 416 SS to make custom match barrels. He has deleted the cryo cycle and instead does multiple tempers after the final machine and finish work and claims better results. To answer the original poster and his question, a cryo cycle on 154CM is very benifical. Quenched 154CM can have as much as 30% retained austenite after the initial quench. A cryo cycle will reduce this down to around 5% as per my metallurgist mentor. The point is it has to be done in the correct sequence and just saying "cryo treated" does not mean that the steel has been improved for a knife blade. Phil

Phil,

If I am reading this right that is what they should be doing in the 1st place to get a proper HT and tempering process so from what you are explaining that is the proper order to achieve a proper HT on a blade so it's nothing special about it other than that's the way it should be done. So in effect they are using a buzz word for doing a proper HT like they should be in the 1st place as marketing.

 

[Gunsnknives]

Thanks again,

So from my metallurgy classes back in the day, this heat treating all sounds familiar...Bottom line...send my knives to Phil Wilson so he can do/fix the HT :thumbup: