steel analysis

[JCPollard]

hello in my recent salt pot thread I HT a knife. My only one of piece of unknown steel from a 48" circular blade. I have 2 of these blades and neither are worth using on my sawmill so I thought I would see what happened if I made a blade from one. It hardened for sure as I annealed it to grind and profile and after the quench it was hard and a file skated on it. I don't want to make a mess of blades from unknown steel so I asked a friend to test it when I was at the scrap yard.
The analysis doesn't seem complete but this is what he said it contained. He works in the SS section and maybe the spectrograph isn't calibrated for everything. I really don't know. He did test the piece I had already heat treated so maybe that had an affect.
Fe 95.13
Ni 3.01
Mn .99
Cr .23

that is it. No carbon or anything else. I researched the content and found it something like 203E with less Ni and carbon and more Mn. Just curious what your opinions are. I know in the future before I work with a steel I will have it tested if the quantity I have is worth wasting a favor.

I definitely understand the rationale of buying known steels . It makes sense and will get there eventually. Just learning and enjoying the journey so far.

Thanks for any input.

James

[Doug Lester]

If there is not any carbon then it's not steel. Without carbon it wouldn't have quench hardened; it can't form martensite. Personally, I don't think that analysis makes sense. I see not reason that anyone would put that much nickel, manganese, and chromium in iron. There is also room enough in that assay for 64 points of carbon and there has to be more than just a little in there if you are getting it to quench harden enough to skate a file. Iron will not do that; low carbon steel will not do that.

While the chromium level is not very great that steel should be moderately deep hardening, especially when combined with with 0.99% manganese. Not as deep hardening as 5160 but more than 1060. The nickel is not listed in my references as promoting depth of hardening but that much should contribute to toughness and strength. I can't help but think that most of that 0.64% of something not listed is carbon. If there is someplace else around where you're at that will do an assay, even if you have to pay for it, it might be worth while being that you have two 48" discs of that steel. Then it will no longer be a mystery metal.

Doug

[Gary Mulkey]

Was it a solid or insert tooth blade? If it was a solid tooth blade then it would need the carbon for edge holding. If an insert tooth blade then your guess is as good as mine as to carbon content.

Gary

[Ed Caffrey]

That sounds very much like the makeup of an "insert tooth" blade. The high nickel content is the give away.

[JCPollard]

Thanks for the replies Doug , Gary and Ed. I did some more specific searching and it seems they did use a lot of nickel in making circular sawmill blades to make them tougher . The content was lowered over the years. From what I read . Possibly as high as 10% 100 years ago down to 5% and lower as the price of nickel increased it seems. This is just what others have said who worked in the supply side of steel plate for mill saws. The blades I am using are the inserted tooth type. I am not going to make it a priority to get further analysis since I need other things for the shop right now but maybe it has some promise. I am learning to appreciate the advice of leaning towards known steel. I really don't won't to make mediocre knives that is why I am here.
Getting a piece that has been hardened , not tempered Rockwell tested. Would that tell anything about carbon content ?. My 1st part of HT for it was 5 min soak at 1500 and quench in preheated sae10 oil. Never tempered
Sorry if I am beating a dead horse but have suffered many bumps on the head over the years

[Doug Lester]

Well, the grain structure looks good so it looks like a soak at 1500 degrees didn't grow it. The fact that you can get to harden enough to skate a file across it would mean to me that it has at least 40 points of carbon in it. That's not much when it comes to making knife blades but then it could be well above that point too. At this point, without an accurate assay, it's still just mystery metal and we're just guessing at things here.

Doug

[GHEzell]

Originally Posted by Doug Lester

I can't help but think that most of that 0.64% of something not listed is carbon.
Doug

I agree. Nice fine grain, too.

[boatbuilder]

I have taken known/unknown steel to our local steel scrap yard for analysist as well. Same thing, it shows no carbon content. They told me that their machine wont show carbon content.
Jim

[JCPollard]

further analysis when I can. I am really liking this part of the knife making process. One day when I have the extra money I am going to buy the Heat Treater's Guide: Practices and Procedures for Irons and Steels By Harry Chandler.

thanks again .

James

[JCPollard]

Jim , That makes sense. I am going to call around today. See if any place local does analysis. If I can get a hardness test done I am thinking if it is in the low 60's or better I have something. If not maybe I will use it for other tools or make some damascus one day.

James

[Doug Lester]

James, there are better books out there than the Heat Treater's Guide unless you are wanting a lot of information on a wide variety of steels, most of which can't be used for knife making. I would recommend Metallurgy Fundamentals and Steel Metallurgy for the Non-Metallurgist. Both are rather short books, around 200 pages, and concentrate on the basics. The do overlap some and the former goes beyond ferrous metals but they also compliment each other. One's stronger in one area where the other is weaker. I recommend that you get and study them both.

Another source of information is ASM International, who, by the way, publish the latter book as well as the Heat Treater's Guide. You can subscribe to their information service for free and then you can download a lot of data sheets and other interesting short articles for a modest fee, like $15-20, directly to your computer. They also hold the articles in your account so that you can access them at any time.

In a way it make sense that a scrap yard is more concerned with alloying elements, other than carbon, more than they are concerned about the carbon. A foundry is going to be more concerned about the manganese, chromium, nickel, vanadium, and the like that is going into the melting pot than they are the carbon. It's easier to adjust the carbon level in the melt to get the mix right.

Doug

[JCPollard]

Doug thanks I will look into those books when I get ready to buy. Which would you purchase first if YOU could only afford 1? . I really do need a knife making book as well.

James

[Doug Lester]

I would purchase Steel Metallurgy for the Non-Metallurgist if I had to choose. I think it gets into the why things happen the way that they do more than Metallurgy Fundamentals plus is written a little more with the knife maker in mind. Metallurgy Fundamentals is a lot better on explaining how to read and interpret carbon phase and isothermal transformation diagrams.

Doug

[JCPollard]

Doug , thank you again!.

James

[Kevin R. Cashen]

The giveaway for me was when you said you had the test done by a friend at a scrap yard. Spectral analysis is done by measuring the spectrum of light given off from the sample and determining chemical elements present based upon the area of the spectrum it is in, it is the same way we can tell what stars thousands of light years away contain. Metal alloying elements are neighbors in the color spectrum, but carbon lives in another part. For a sorting yard a $20,000 hand held gun that reads the heavy metals is the most economically effective choice rather than the $50,000+ units that read the wider array, thus rarely will you get a carbon reading from a scrap dealer. I bought some ?O2? once that couldn?t have had more than .35% C, but couldn?t convince the dealer it was anything but O2 because his gun gave him all the alloying for O2, so the guns are fin so long as the user understands their limitations.

I am still hoping to figure out how to have a spectrometer one day, but until then I can get in the ball park with the metallograph. Levels of pearlite present and the presence of plate martensite are dead giveaways of at least localized levels of specific carbon content exceeded.

I am an advocate for reading ?Metallurgy Fundamentals ? before moving on to ?Metallurgy For the Non Metallurgist?, for helping in full comprehension of the latter, but more importantly to help eliminate some of the gross misinterpretation by knifemakers I have seen of the concepts Verhoeven describes.