test report for high nitrogen steel---HNS Yushu

stevomiller said:
Guys, this steel is going to be more along the lines of H1 like Spyderco uses. Comparing it to non-stainless tool steel is an apples to oranges at best.
Yushu, thanks for sharing your progress and all the info.
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I was thinking along the lines of workability.

H1 is a work hardening steel and I think it starts @ HRc 57???? I don't know for sure cause I couldn't find out much about it. I wonder if Spyderco hot stamps the blade then polishes before assembly?

If Yushu can be cold worked and heat treated similar to A2 with similar hardness/toughness but enhanced corrosion resistance then that's a plus. It's years off, but a side by side comparison with N360 would answer a lot of questions.
 
Chuck Bybee said:
Here is a comparison of 5 nitrogen steels:

Tbl--Elements.gif
Tbl-H1.gif
Tbl-N360.gif
Tbl-N680.gif
Tbl-Vanax.gif
Tbl-Yushu.gif


Yushu is close to Bohler N360.

The nitrogen steels are making a big impact in the knife community. Spyderco has been using H1 for years. Benchmade uses N680. I like both steels but prefer N680 because I think it holds an edge better.

We've been using Vanax at HRC 59 for about two years and we are very impressed with the edge holding. It compares with S30V but it is much easier to sharpen.
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the content of Cr and Mo in Yushu is slightly higher than N360, and we add 0.54% nickel.
 
Yushu_withwind said:
the content of Cr and Mo in Yushu is slightly higher than N360, and we add 0.54% nickel.
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So, you are working towards greater impact resistance at a given hardness and enhanced corrosion resistance? While maintaining good machinability?
 
stevomiller said:
Chuck, thanks for throwing up that chart of various nitrogen steels, and for sharing your personal experience. Yushu, in reviewing the spectro-analysis it appears that there is sufficient boron and manganese to be aiding the hardenability of the alloy, even though you do not show it in your final summary. I imagine that removal of these two items will cause your alloy to behave much differently.
Best,
Steve
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boron is esidual elements in the steel,not intentionally added.boron improve quenching degree similar to molybdenum,but the content of 0.001% has little effect on the 1.3%Mo steel.

In fact, we try to avoid boron in the steel, because boron is easy to form nitride of BN which is harmful to the steel.
 
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Regarding the constituents of H1 in the table above, I believe that the Nickel and the Nitrogen values are interchanged. It is unlikely that a substance containing 7% Nitrogen by weight would be metallic. -Doug
 
Maddogg774 said:
How did you introduce the desired amount of nitrogen? Gas or liquid?
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Nitrogen is known as the element that can enhance not only corrosion resistance but also toughness for martensitic steel.However,the highest nitrogen concentration introduced in steel have been limited to 0.15% under conventional atmospheric pressure melting method.Inorder to solve the problem,pressurized electroslag remelting method ha been used in our process.in addition, silicon nitride is also added into the consumable electrodes during electroslag remelting.
 
I read somewhere that quenching in ammonia has given some the desired nitrogen and hardened the surface.
 
Quenching in ammonia? Kinda dangerous, isn't it. Doesn't that stuff burn and explode well well?

Just inquiring. Future bladesmith here.

Larry
Tinkerer
 
tinkerer said:
Quenching in ammonia? Kinda dangerous, isn't it. Doesn't that stuff burn and explode well well?

Just inquiring. Future bladesmith here.

Larry
Tinkerer
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I believe he was referring to either ammonia in water (ammonium hydroxide - the stuff used to clean with) or ammonia gas (like air quench) or liquid ammonia (either real cold or high pressure). I believe you are thinking about ammonium nitrate (a solid - the stuff that blew up the tanker in Texas City harbor when it got real hot).

The fumes from ammonia gas, in high enough concentrations, are dangerous.
 
Generally speaking, There are three ways for surface nitriding: gas nitriding , ionic nitriding and salt bath nitriding. gas nitriding typically use ammonia or mixed ammonia/nitrogen at 400-600C,but the nitrided depth is noly about 0.02mm,it is not fit for blade.
 
good work putting your name in english in a romantic way. and Grats on this new design! btw after all the tests are done, would you like to supply this in sheet for knifemaking?
 
If I am reading things right, the impact resistance is about the same as A2, which as I understand it, is VERY good for a true stainless steel with that much chromium in the mix. With that said, I hope that it has significantly better edge retention and stability than what I have heard that H1 has or it may be a one trick pony limited to salt water pry bars.;)
 
Yes,

Yushu, what's the availabilty of the steel?

How is the edge retention?

Since it's a current topic, can you compare it to INFI?
 
Brian, while the test seems to indicate that it is VERY impact resistant for a stainless steel, it it still appears to be only about 40-50% as resistant as CPM 3V is at 58-60 RC (55 joules vs. around 113 for 3V at 58 and in the 160 range for S7.) I would expect that Infi should be at least somewhere in the 120+ range, but i can't say for sure. I suspect that this steel was designed to be VERY stain resistant and yet still have the impact resistance of some fairly tough conventional tool steels like A2 and it sure seems to have that angle covered.
Brian Ayres said:
Yes,

Yushu, what's the availabilty of the steel?

How is the edge retention?

Since it's a current topic, can you compare it to INFI?
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i think the impact toughness will be a little better if it is done the same way in usa. the hammer head in this impact test has a much sharper shape. while in most of impact test in america they have blunter hammer heads in their mechine.
 
hammerfall said:
good work putting your name in english in a romantic way. and Grats on this new design! btw after all the tests are done, would you like to supply this in sheet for knifemaking?
Click to expand...

Hello, hammerfall, my old friend, I'm 玉树临风 in WWW.Knifriend.com, hahaha

Well, we hope to sell some Yushu for knifemaking outside China,so I'm here.
 
jdm61 said:
Brian, while the test seems to indicate that it is VERY impact resistant for a stainless steel, it it still appears to be only about 40-50% as resistant as CPM 3V is at 58-60 RC (55 joules vs. around 113 for 3V at 58 and in the 160 range for S7.) I would expect that Infi should be at least somewhere in the 120+ range, but i can't say for sure. I suspect that this steel was designed to be VERY stain resistant and yet still have the impact resistance of some fairly tough conventional tool steels like A2 and it sure seems to have that angle covered.
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yes, it is sure that the toughness of Yushu HNS is not as good as CPM3V/s7 level, but I think it could be a good choice during stainless steel. as to edge retention,the same is our concern, we are working on some test, the main concern of the test is ruling out interference with human factors and quantifiable/measurable, than we need to make some special equipment. Estimates that in some days we can finish the test and share the result with everybody.
 
I am trying to translate the numbers in my head, but your steel appears to possibly have impact resistance over twice as high as Crucible's S35VN. The big questions to be answered are what kind of edge retention, edge stability and abrasion resistance the steel has. A2 is fairly tough stuff, but it give up quite a bit in abrasion resistance compared to CPM 3V, 4V and the S30/35 stainless steels.It will also be interesting to see what the grain and carbide microstructure looks like.
Yushu_withwind said:
yes, it is sure that the toughness of Yushu HNS is not as good as CPM3V/s7 level, but I think it could be a good choice during stainless steel. as to edge retention,the same is our concern, we are working on some test, the main concern of the test is ruling out interference with human factors and quantifiable/measurable, than we need to make some special equipment. Estimates that in some days we can finish the test and share the result with everybody.
Click to expand...
 
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