M390 vs 20CV vs 204P - 3rd Generation Powder Metallurgy

Larrin

Larrin

Joined
Jan 17, 2004
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I wrote an article describing the difference in process between different powder metallurgy production companies making knife steels. I also did experiments to analyze the different products including carbide size, impurity levels, and inclusions. And comparisons between toughness of similar steels from different manufacturers. https://knifesteelnerds.com/2020/03...-3rd-generation-powder-metallurgy-technology/
 
Excellent, I've been hoping you'd take a look at this.

My guess before reading it is that there is no significant difference between the processes used by the competing companies.

Edit: What a surprise... It's almost like the steel companies are actively competing with each other. I hope people will quit repeating "bUt thIRd GeNeRAtiOn pM tEChnOloGy" now.
 
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marrenmiller said:
Excellent, I've been hoping you'd take a look at this.

My guess before reading it is that there is no significant difference between the processes used by the competing companies.

Edit: What a surprise... It's almost like the steel companies are actively competing with each other. I hope people will quit repeating "bUt thIRd GeNeRAtiOn pM tEChnOloGy" now.
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Even I was guilty of assuming differences between “3rd generation” and “1st generation” steels were bigger than they are.
 
was the largest variance seen in oxygen levels? - If so, shouldn't that difference show up in toughness testing?... or are the amounts in all cases really so small that it doesn't seem to actually impact performance?

after reading it, I thought it was the latter

could extra oxygen impact any other steel properties?
 
dirc said:
was the largest variance seen in oxygen levels? - If so, shouldn't that difference show up in toughness testing?... or are the amounts in all cases really so small that it doesn't seem to actually impact performance?

after reading it, I thought it was the latter
Click to expand...
I can only say for sure hat I observed in testing. Maybe if you tested 100 samples you would see more low values with higher oxygen. But toughness is kind of inherently variable anyway so it would take a lot of specimens to ensure a true difference was measured.
could extra oxygen impact any other steel properties?
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Maybe corrosion resistance, but I’m not a corrosion expert. I know sulfides can affect corrosion but all of these steels have significant sulfur in them.
 
Larrin said:
I can only say for sure hat I observed in testing. Maybe if you tested 100 samples you would see more low values with higher oxygen. But toughness is kind of inherently variable anyway so it would take a lot of specimens to ensure a true difference was measured.

Maybe corrosion resistance, but I’m not a corrosion expert. I know sulfides can affect corrosion but all of these steels have significant sulfur in them.
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Sulfur is supposed to be one of the worst elements in steel. I know it helps grindability if tiny amounts are used... (saves costs on sanders/belts/etc)

but it's also one of the worst ones in terms of performance... your test subjects ranged from 0.015% upto 0.02% (which seems on the lower end to me... since plain 1095 is all the way upto 0.05%)

normally 51200 is called clean - but has S = 0.025%... but I think one of the cleanest is super blue = 0.004%
 
dirc said:
Sulfur is supposed to be one of the worst elements in steel. I know it helps grindability if tiny amounts are used... (saves costs on sanders/belts/etc)

but it's also one of the worst ones in terms of performance... your test subjects ranged from 0.015% upto 0.02% (which seems on the lower end to me... since plain 1095 is all the way upto 0.05%)

normally 51200 is called clean - but has S = 0.025%... but I think one of the cleanest is super blue = 0.004%
Click to expand...
You are citing sulfur maximums which are what are typically shown on specifications. They don’t usually show what the “real” sulfur content is such as the average value or the typical range. The Uddeholm 26C3 steel I analyzed had 0.001% sulfur even though their spec says 0.011% max.
 
Excellent article thanks !
I’m wondering if you would consider studying the effect of various quenching methods.
Specifically the use of canola / parks aaa / parks 50 etc... on frequently used steels like 1084 and 80crv2...
There is alot of opinons on the net but not much data
 
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