Modified heat treat and missing data

JTknives

JTknives

Joined
Jun 11, 2006
Messages
8,650
I have been trying to brush up and do research on heat treating. In the process one thing became very clear and that is most of the time industry standard heat treat is not the best option for blades. This is apparent in steels like D2 and especially 3V. Let's look at 3v for a sec, standard say high temper temp and blade smiths say no that's wrong 400° is much better. But what's weird is when you look up the graphs for this steel thy don't even include the low temp on the graph. Why is this, why don't thy show the hardness and wear resistance starting from the "as quenched" state. Are thy trying to hide something or just don't think it's important.

This is a tread I see in other steels as well like CPM 10V. With 10V thy start at 1000° and show hotter options but nothing in the low range. I find it hard to believe that this steel and others are not affected by tempering temps from 400-900°. Proof is in the pudding and 3v has proven that using liquid nitrogen to complete the heat treatment is much more effective for a blade then tempering hotter and hitting that hardness bump. This makes me wonder what can be achieved with these other steels that are missing data from the low end of the chart. Do these other steels have high temp hardness bumps, are thy really not affected by low temp tempers and do thy play nice with cryo.

Sorry for my random rambling but it just bugs me when I cant see the whole picture of what's going on. There has to be more to the story then thy are showing and I must know what it is.
 
My understanding from discussions with others is that the LN cryo is always a good idea. It may not significantly improve some steels, but it will do no harm to any steel. The higher the alloying and come complex the carbides, the more benefit from cryo.
 
I have some 10V test blades with LN soak and a 350 temper but I haven't had a chance to test them yet. You will get opinions on both sides of any H/T issue so do yourself a favor and try it for yourself then there will be no doubts.

BTW, the reason for the 350 temper is because that is the minimum that Brad Stallsmith suggests for PM steels. I hardened at 2000 so the blades SHOULD have MAX. hardness. I'll know once I get a chance to finish and test.
 
you need to look at what these tool steels were made for. knife makers and the cutlery industry use little steel. CPM3V was developed as an alternative to S7(gets harder) and A2(more shock resistant), think punches, dies, chisels. CPM10V an alternative to D2 and M2 for use by the plastics industry. S30V as a replacement for 440C in bearings, engine parts, and food processing. nobody at crucilble is looking at how a 12x2x1/16" piece of CPM heat treats or that 1000F is the wrong starting point.
scott
 
Darrin Sanders said:
I have some 10V test blades with LN soak and a 350 temper but I haven't had a chance to test them yet. You will get opinions on both sides of any H/T issue so do yourself a favor and try it for yourself then there will be no doubts.

BTW, the reason for the 350 temper is because that is the minimum that Brad Stallsmith suggests for PM steels. I hardened at 2000 so the blades SHOULD have MAX. hardness. I'll know once I get a chance to finish and test.
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I'm planning on doing some testing once the dewar is delivered which should be today. But that's what I'm wondering you said 350° temper should be max hardness. What happens between your 350° temper and the 1000° temper that's listed as industry max hardness. Does the hardness drop as you increase the tempering temp then once you get to the 900-1000° range the hardness spikes back up? If so then why not show that in the graph. And if this is what happens then that means there should be a lot of performance floating around somewhere in the lower tempering range. And if thy are running 1000° tempers to convert the retained austionite then we can take care of that at the lower end with cryo. Just like with D2 and 3V we know that the hardness bump at the higher tempering temps is not optimum for blades. Which has me thinking that if CPM10V has a hardness bump at the 1000° and preforms amazing what can we get out of it if we use cryo and low tempers.
 
I think the reason for this is two fold.

One, the steel and it's HT are made for applications like tool and die where it's important the finished work doesn't grow from HT. The SHH and stabilized RA help the hardened piece remain basically the same as it was when soft. The cold temp tweaks results is significant dimensional growth.

Two, the HTs are optimized based upon verifiable measurements they can easily quantify such as Rockwell hardness, joules of energy absorbed in a breaking impact, material lost in abrasive wear. While these values are important, they don't always predict the behavior of a knife edge. A stamping die may perform well when given the SHH and with stabilized RA, but areas of softer (weaker) martensite, larger carbides and soft RA play hell when found in the narrow width and small scales of an edge. <--- geometry not generally found in other applications.

So, I think it's a combination of designing for a different application, and lacking the tools to make meaningful judgments for our particular niche.
 
To add to Nathan's post, I think you've pretty well nailed the answer already. The "industry standard" is what the steel is primarily used for. In D2 there is a lot of use in planer & joiner knives, so the HT is set to maximize the cutting which turns out to be at about 62-64. Since this is a fairly large use for the steel, the HT is looked at from the point of view of a knife spinning at high speed & cutting hardwood or softwood. That's not saying it can't be treated differently in completely different applications, but if it's being sold to an industry which has a specific application, why not use it there & point the marketing at this niche to sell the product?
 
Hi, I know it's an old discussion but I would like to know if the low temperature tempering 10v blades have been tested? There are updates?
 
Wow a blast from the past.
From my research it seams like the steels that benefit from the modified heat treat are the ones that use the high temp to wrangle the retained austenite into submission. I have not done any testing on 10V but it’s funny because Salem just gave me a stick of CPM10V.
 
Willie71 said:
Check out knifesteelnerds.com
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With all due respect but this is www.bladeforums.com and he ask question HERE . I would like to read answers from other members HERE , not on other site .I have nothing against that site , on the contrary I read lot of things there and find lot of answers ..... I like that site BUT my friend ....... it is not good to send members there for each question they have ASK here .What is the purpose of this site , if we respond to every new topic/question with a link to other sites.......???
 
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Natlek said:
With all due respect but this is www.bladeforums.com and he ask question HERE . I would like to read answers from other members HERE , not on other site .I have nothing against that site , on the contrary I read lot of things there and find lot of answers ..... I like that site BUT my friend ....... it is not good to send members there for each question they have ASK here .What is the purpose of this site , if we respond to every new topic/question with a link to other sites.......???
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Natlek - I think I understand what you are trying to say, BUT, I don’t think any one site can claim to have all the knowledge there is to be had. If you can assume, as I do , that the objective is to make knowledge available, and that can be done by saying “go look at this other site” .... why not do so?
 
Cushing H. said:
Natlek - I think I understand what you are trying to say, BUT, I don’t think any one site can claim to have all the knowledge there is to be had. If you can assume, as I do , that the objective is to make knowledge available, and that can be done by saying “go look at this other site” .... why not do so?
Click to expand...
I understand that. BUT i think that we need answers on questions here .What the purpose of any topic opened here would be if we just make links to other places ? Maybe we should answer like this .....Go in library and find/read books about your question ,all knowledge is there ..
 
I think what we have here is the best of both worlds. The author of those sources is active on this site. He can clarify or add points, but shouldn't retype his website every time there is a question.
 
Natlek said:
With all due respect but this is www.bladeforums.com and he ask question HERE . I would like to read answers from other members HERE , not on other site .I have nothing against that site , on the contrary I read lot of things there and find lot of answers ..... I like that site BUT my friend ....... it is not good to send members there for each question they have ASK here .What is the purpose of this site , if we respond to every new topic/question with a link to other sites.......???
Click to expand...

Natlek, your response is unfounded and duplicates efforts. By regurgitating answers on here, information could be passed on incorrectly. There are also issues with duplicating content. What if knifesteelnerds articles are updated when new information is found. Now we have an out-of-date forum post. Always point to the source of truth.
 
Natlek said:
I understand that. BUT i think that we need answers on questions here .What the purpose of any topic opened here would be if we just make links to other places ? Maybe we should answer like this .....Go in library and find/read books about your question ,all knowledge is there ..
Click to expand...
Not a bad idea :-)
 
Natlek said:
I understand that. BUT i think that we need answers on questions here .What the purpose of any topic opened here would be if we just make links to other places ? Maybe we should answer like this .....Go in library and find/read books about your question ,all knowledge is there ..
Click to expand...

check the stickies.
 
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