Anybody know about this Chinese steel?

[knarfeng]

I did the math; you even quoted it. 440A - HRC 55-57. 440B - HRC 57-59. 440C - HRC 57-59. 7Cr17MoV - HRC 58. And, no, it's not 7Cr14MoV that we're talking about... I don't even know what that is.

It's 7Cr17MoV, and it has 3% more Chromium than the 8Cr14MoV that you've used, which I'm sure you realize also contributes greatly to hardness and edge-holding. In fact, A.G. Russell site I linked suggests that it takes more than 14% Chromium to produce high-carbon stainless steels.

Chromium
Produces hardness and better edge holding when combined with other alloying materials. Used in fairly large amounts, it produces a blade that resists rust. Takes over 14% to produce high-carbon stainless steels. Expressed as Cr. http://www.agrussell.com/Knife-Encylopedia/a/110/

Seems like some folks believe carbon to be the end-all element in steel, and that formulas with less of it can't make a good or great steel... which is, of course, absurd. H1 steel has .15% carbon (1 tenth that of 440C), and typically has a HRC of 65-68. Sandvik 12C27 has less carbon (about half of what 440C has) than the 7Cr17MoV too, yet readily produces HRC 57-59. Each element alters the properties of the resulting steel, and ignoring their qualities or their quantity in a formula means a less than accurate assumption or opinion about its "grade".

I enjoy the debate, because it forces me to do a lot of homework, and I love research. As is often the case with steel, makeup is only half the story... the treatment seems every bit as important as the content.

You are obviously "debating" about that which you don't actually understand, if you are just now "doing your homework". And you are drawing incorrect conclusions from your 'homework'. Understanding cutlery alloy is not a quick study. People spend years to reach any type of understanding.

Wherever did you get the idea that the normal hardness of H1 is 65-68HRC?
When I actually measured the hardness of my Spyderco H1 Pacific Salt blade it was 56.5. Not even close to your numbers, and the edge retention of H1 matches what I would expect from the hardness I measured. H1 is a PH steel. It hardens through a different process than 440C, so comparing its Carbon content to that of 440C is ridiculous. Meanwhile, 7Cr17MoV hardens through exactly the same process as 440C, so Carbon content IS important to its performance.

The reason Chromium increases edge retention is that it forms Chromium Carbides with the Carbon in an alloy, but you have to have the Carbon there to do so. At .7% Carbon, there is not sufficient Carbon to form the amounts of carbides necessary to match the performance of 440C. At .7%, most of the Carbon stays in the iron matrix. Not to mention that both 440C and 7Cr17MoV have 17% Chromium, so you are back to comparing an alloy with .7% Carbon to one with over 1%.


7Cr17MoV is not the same as 440C

 

[Knifein]

It's a good steel.

 

[singularity35]

I have a Meyerco Wharning in 7Cr17. It takes a pretty good edge and holds it reasonably well(almost as well as spyderco's 8Cr13Mov). I'm pretty much satisfied with how the steel in my wharning performs at the price I got it at.

 

[Bill1170]

The Russell guide lists HRC 65 of H1 as standard or "typical", while Spyderco (with Crucible doing the testing), routinely got HRC 65 at the edges of the PE Salts and 68 at the edges of serrated edge Salts, as you said. I have no clue what VG-10 has to do with the discussion, as that isn't in any of the previous posts; and I haven't seen any claims either way about that particular steel.

In any event, the point was that even with one eighth as much carbon as a 440C blade, an H1 blade with a different makeup, with additional elements in its alloy, and a different treatment, still reached a superior hardness than the 440C blade. The illustration was only meant to show that carbon content is far from the only pertinent characteristic to hardness, toughness, or edge retention.

Even if the Spydercos only attained a rating of 60, which is far below the ratings they've achieved and published, it's still greater than the 57-59 one can expect from a 440C blade with nearly 8 times the carbon content of the H1 blade.

My own experience with the plainedge tip of my SE Pacific Salt is that it dulls much faster and rolls easier than my VG-10 Spydercos. I also have read where Sal said that the SE H1 attained up to Rc 68, but I have never read that the plainedge Salts were at 65, and my personal experience does not support such a conclusion.

What may be happening with the testing by Crucible that you reference is that the extreme edge is at Rc 65 and the metal 0.1 mm behind this extreme edge is at Rc 56, so that the edge rolls back where it is soft, not at the bitter edge where it is hard. I am theorizing a mechanism that could explain my own experience and also the test results you mentioned.

In your own experience, how does the edge-holding performance of non-serrated H1 compare to other common high end cutlery steels that you use on a regular basis? I would like to learn more about this fascinating topic, and thank you for taking the time to reply to my query.

 

[XanRa]

This is a fun debate

The only similar steel I have Experience with is 8cr14mov and I personally like it alot

My only 2cents back to debating percentages, alloying properties, and bonding have fun!

 

[Cold Kill]

I love my Byrd Raven in 8Cr13MoV. It seems like the Chinese steels have really upped the ante by being cheap and performing well. My Byrd takes an amazing edge, holds it long, and seems to hold oil well (oiled then cleaned the blade at the beginning of the year, it still feels like I oiled it yesterday). Chinese steels are redefining the knife market. For the better.

 

[A. G. Russell]

In fact, A.G. Russell site I linked suggests that it takes more than 14% Chromium to produce high-carbon stainless steels.

Chromium
Produces hardness and better edge holding when combined with other alloying materials. Used in fairly large amounts, produces a blade that resists rust. Takes over 14% to produce high-carbon stainless steels. Expressed as Cr.

http://www.agrussell.com/Knife-Encylopedia/a/110/

Seems like some folks believe carbon to be the end-all element in steel, and that formulas with less of it can't make a good or great steel... which is, of course, absurd. H1 steel has .15% carbon (1 tenth that of 440C), and typically has a HRC of 65-68. Sandvik 12C27 has less carbon (about half of what 440C has) than the 7Cr17MoV too, yet readily produces HRC 57-59. Each element alters the properties of the resulting steel, and ignoring their qualities or their quantity in a formula means a less than accurate assumption or opinion about its "grade".

I enjoy the debate, because it forces me to do a lot of homework, and I love research. As is often the case with steel, makeup is only half the story... the treatment seems every bit as important as the content.

Many thanks for bringing that errorl to my attention. I am pretty sure that the correct figure is 12.5% and NOT 14%

 

[hardheart]

this should help http://www.calphad.com/martensitic_stainless_steel_for_knives_part_1.html

the important percentages by weight are those of the austenite. The heat treat protocol is going to effect the carbide volume, attainable hardness, corrosion resistance, and the impact toughness. How much carbide you get and whether or not they're in the grain boundaries is going to cause issues.

 

[jtbca]

I just found this thread and what blows me away is Byrd can make a better knife with better steel than Gerber and charge a 1/3 of the price. Sorry Gerber you lost a customer... looks like the Instant is off the list and a Byrd Flight is back on.

 

[440C knife steel]

I am chinese, i know 7Cr17MoV equals to 440A. But it's better than 7Cr17 which also called 440A.

For 440C steel, chinese grade 9Cr18MoV 9Cr18Mo or 9Cr18, 11Cr17.
Many factories who produce knives intended to give a misunderstanding of these grades.

 

[440C knife steel]

uhhh...
as a chinese, i need to say, many steel grades are developed and produced as per customers' requests.
By adding other elements like Mo Co V, the property will have a greatly improvement.

So for 440A, 7Cr17 and 7Cr17MoV are the same defination.
Taylor knife use this grade.

After digging Chinese steel standards, I can't say the picture is any clearer.
As others pointed out, 7Cr17MoV is equivalent of 440A, not 440C.

However, the interesting part is that, there is no 7Cr17MoV steel neither in GB/T 20878(Stainless and heat resisting steels) nor in GT/T 1220(Stainless steel bars) standard specifications. Only 7Cr17 steel is.
While both standard list up to 0.75% Molybdenum in the 7Cr17 composition, Vanadium is not mentioned at all. There are some sources, listing it with 0.04% Vanadium, but that's very little to seriously affect steel performance. Considering that CPM 154 contains 0.40% Vanadium and maker says it's "residual", I suspect, 10 times less Vanadium is not gonna be anything significant.

There is a trio of 9Cr18xx which matches naming pattern with composition more precisely:
9Cr18 - Doesn't have neither Mo nor V;
9Cr18Mo - 0.40-0.70% Mo;
9Cr18MoV - 1.00-1.30% Mo and 0.07-0.12% V;

If anyone has more precise info on 7Cr17MoV, please let me know.

 

[recon1s14]

So this is where the really smart people hang out.....Ok I'm game

 

[Gator97]

uhhh...
as a chinese, i need to say, many steel grades are developed and produced as per customers' requests.

Thanks for the info. So, for my steel chart purposes, can I assume 8Cr13MoV and 8Cr14MoV are non standard, developed specifically for some customers?

 

[dragonsprayer]

first off china steel is not a company and they have million little makers some make good and some make crap

if ii is cheap and you like it plan on throwing it away if you use it alot or spend more on sharpen stuff then the knife is worth.

stick with real still 440c or better aus-6 is ok if you can trace it too company and get specs then ok.
but like everything in china it is generic

could be golden or bunk - probably bunk

 

[dragonsprayer]

i worked in steel mills since i was 16, i am material engineer - not too pull out the cred crap

but...... there is a lot too making steel, from the coke too the iron ore or scrap in mini mill. degassing desulf dephos

alloy trimming

china steel even from large company could be junk one day good the next and junk later that is why they use generic term

440c has specific method too make it - in japan they had change the alloy name too make it close or better.

china is crap - i take paki damscus at least they take real steel and fold it.

you get load of knives that kick butt then they are crap, they they go ebay as seconds then they become firsts then...... ok i beat this bush too death.


ASK DO: do they qc the slab, each one. what are the standard tests, where is it heat treated in china? do they have a element analysis? final QC on the finished product?

you ever notice every paki damscus has the same hardness! lol! buy



BUY CHEAP KNIVES FROM GOOD STEEL NOT EXPENSIVE KNIVES FROM CHEAP STEEL!!!! the dragons pray

 

[440C knife steel]

chinese made knife steel 7Cr17MoV equals to 440A, but not 440C.
440C, 9Cr18MoV.
Aus10, 9Cr13MoVCo is similar to 440C.

In China, for 440C, thickness is above 4mm.
Can somebody tell me that plant can produce thickness below 4mm, like 2mm?

 

[440C knife steel]

yes, when customers have its special applications, plant researches and developes, and then massive production.

For 8Cr13MoV or 8Cr14MoV, it equals to Aus8, japanese steel.
In China, we develop it as per Aus8 standards.

there are many kinds of steel grades we develop like 4Cr14MoV 5Cr15MoV 6Cr14MoV......

Thanks for the info. So, for my steel chart purposes, can I assume 8Cr13MoV and 8Cr14MoV are non standard, developed specifically for some customers?

 

[440C knife steel]

Sir, it's not exactly as what you say.

There are many plants everywhere, not everyone can produce prime quality.
If customers wanna prime quality at cheaper price, this will be a big mistake.
Prime quality, better price!

For us, if i say our products have exported to Japan plant, monthly 1500tons, what do you think of that?
Junk exported to Japan??? and then Japan export these craps to other countries?

i worked in steel mills since i was 16, i am material engineer - not too pull out the cred crap

but...... there is a lot too making steel, from the coke too the iron ore or scrap in mini mill. degassing desulf dephos

alloy trimming

china steel even from large company could be junk one day good the next and junk later that is why they use generic term

440c has specific method too make it - in japan they had change the alloy name too make it close or better.

china is crap - i take paki damscus at least they take real steel and fold it.

you get load of knives that kick butt then they are crap, they they go ebay as seconds then they become firsts then...... ok i beat this bush too death.


ASK DO: do they qc the slab, each one. what are the standard tests, where is it heat treated in china? do they have a element analysis? final QC on the finished product?

you ever notice every paki damscus has the same hardness! lol! buy



BUY CHEAP KNIVES FROM GOOD STEEL NOT EXPENSIVE KNIVES FROM CHEAP STEEL!!!! the dragons pray

 

[knives4less]

Anything from Gerber, not so much... Don't know what they do to their steel or who they get it from, but in the last three years the edges on my Gerbers seem to fall apart faster than I can sharpen them. Their 'mistake' in quoting 7Cr17 as a 440C equivalent and their lack of advertising their steel type is proof that their business model is less than ideal.

I found this quote on the China Market website in the late 1990's. It has since disappeared.

"Wayeah Knives & Tools Co., Ltd. is a professional manufacturer and exporter of knives & tools, located in Yangjiang, Guangdong, China. Several years ago, they decided to build the world’s largest knife factory. To aid in the building and set-up, they contracted Gerber Legendary Blades. They then decided to produce the highest quality knives in the world. To this end, they located some of the master craftsmen who were laid off when Case stopped making their own knives in 1994. These master cutlers were invited to come to China and teach the Chinese how to make the old Case knives. Some stayed only a short time but others now make their homes in China, where they are still sharing their expertise. The knives are largely handmade. One thing the Chinese have is plenty of labor. Absolutely no corners are cut in the search for perfection.

“This is what Wayeah stands for! Wayeah always works with earnest attitude and excellent credit on a mutual-beneficial base. Working with us will greatly cut down the cost and win the market.”

 

[Segol123]

http://apg2k.hegewisch.net/blade_steel.html

This link might help answer your question.