# 9xc3 Steel



## enrico l (Dec 15, 2022)

Anyone have any readily available info on this steel? Haven’t seen it before and can’t seem to find anything on a web search. 

Cheers


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## McMan (Dec 15, 2022)

If 9xc3c is the same as 9xc3, then this should help:


GOST 9KHS Knife Steel Composition Analysis Graph, Equivalents And Overview Version 4.36


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## Troopah_Knives (Dec 15, 2022)

I'm not really sure where the Z-Knives notes on this one are coming from as this steel has no Co addition(looked into it there is stell listed as an equivalent called 90CrSi5 which does have a Co addition). 9xc3 is kinda strange steel if that published composition is to be believed. It seems to be in that familiar 52100-ish range but with a pretty large silicon addition. Interestingly it's pretty similar to the alloy looked at in this paper that Larrin covered in his article on the effect of silicon in steel. If someone knows where to get it shoot me a note, please!


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## Barmoley (Dec 15, 2022)

It is a Russian low alloy steel 0.9 or so carbon 1 chromium (X), about 1 Si (C) 3 is for 0.3 Mn.


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## enrico l (Dec 16, 2022)

What is the desired value of this when talking about kitchen knives. I know you look for a sweet spot with all the trade-offs and other factors.

I know I’m kind of jumping into the rabbit hole but was just wondering how bad a value of the lower end is vs mid vs high.


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## Troopah_Knives (Dec 16, 2022)

enrico l said:


> What is the desired value of this when talking about kitchen knives. I know you look for a sweet spot with all the trade-offs and other factors.
> 
> I know I’m kind of jumping into the rabbit hole but was just wondering how bad a value of the lower end is vs mid vs high.


The eternal debate of how much toughness matters in kitchen knives. I think the best answer here is we really don't know. We have a decent grasp of its effect on limiting chip size but there are additional mechanisms where toughness is of concern the biggest of which is low cycle fatigue (I usually call this microchipping people's use of that term differs). Simply put more testing needs to be done in the realm but in general, if you are getting chips a steel with better toughness could be the answer as you can maintain the same thin geometry.


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## enrico l (Dec 16, 2022)

Troopah_Knives said:


> The eternal debate of how much toughness matters in kitchen knives. I think the best answer here is we really don't know. We have a decent grasp of its effect on limiting chip size but there are additional mechanisms where toughness is of concern the biggest of which is low cycle fatigue (I usually call this microchipping people's use of that term differs). Simply put more testing needs to be done in the realm but in general, if you are getting chips a steel with better toughness could be the answer as you can maintain the same thin geometry.


Interesting. 

Another question! Is there a reason to use silicon over other deoxidizing agents? Seems to be quite high in this steel.


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## Troopah_Knives (Dec 16, 2022)

enrico l said:


> Interesting.
> 
> Another question! Is there a reason to use silicon over other deoxidizing agents? Seems to be quite high in this steel.


This was my point in linking Larrins article that the silicon addition must (90% sure) be added to allow the steel to be tempered at a higher temp than normal. This is either to allow for higher toughness or maybe to improve its characteristic in higher-temp working conditions as a sort of cheap hot work steel replacement. Si additions this high are not for deoxidizing. It's a very strange steel I'd be interested in getting some to compare to 52100.


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## enrico l (Dec 16, 2022)

Troopah_Knives said:


> This was my point in linking Larrins article that the silicon addition must (90% sure) be added to allow the steel to be tempered at a higher temp than normal. This is either to allow for higher toughness or maybe to improve its characteristic in higher-temp working conditions as a sort of cheap hot work steel replacement. Si additions this high are not for deoxidizing. It's a very strange steel I'd be interested in getting some to compare to 52100.


That was a good read. I’m not seeing any downsides to the silicon addition. Any thoughts?


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## Troopah_Knives (Dec 16, 2022)

enrico l said:


> That was a good read. I’m not seeing any downsides to the silicon addition. Any thoughts?


Silicon has some pretty complex effects on the carbide structure of steel and can reduce the hardness-toughness balance when tempering at lower temperatures. I don't think this has been fully explored. I would be interested to compare both the hardness vs tempering temp and hardness vs toughness curves of 9xc3 with a 1% C and 1% Cr steel to see how these might differ.


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## Barmoley (Dec 16, 2022)

From the description of the steel it sounds like it is used for applications where you need resilience when bending, twisting repeated and over time so prolonged resilience under stress. So sounds like more of a "toughness" requirement, even though not specifically shock resistance, the way we use toughness. Doesn't sound like high temp resilience is the primary requirement, but it is used for drill bits and circular saws as well. It is also mentioned that it is prone to becoming brittle due to overheating. Testing it against 52100 or similar would be very interesting.


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## Troopah_Knives (Dec 16, 2022)

Barmoley said:


> From the description of the steel it sounds like it is used for applications where you need resilience when bending, twisting repeated and over time so prolonged resilience under stress. So sounds like more of a "toughness" requirement, even though not specifically shock resistance, the way we use toughness. Doesn't sound like high temp resilience is the primary requirement, but it is used for drill bits and circular saws as well. It is also mentioned that it is prone to becoming brittle due to overheating. Testing it against 52100 or similar would be very interesting.


yeah, that high fatigue requirement is something that toughness is good for that's why steels like 9254 have similar Si additions. The reason I brought in the high temp point is that 90CrSi5 which 9xc3 is marked as an "equivalent" to has a Co addition which implies some resilience at high temps is part of the design. Maybe just to increase the range of working temps for the alloy.


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