Mystery steel

J

jtwodogs

Joined
Feb 1, 2009
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421
A friend of mine who works for Siemens gave me some steel supports used in transport of their monster chemistry analyzers.
They are plates that are 2 3/4x14x .25
They are painted but feel quit dense. There is a place where the paint flecked off and took some rust. There is also a place in the metal where it was threaded and took some 1/4 stainless bolts.
I guess do a grinder test to look for a large spark shower?? Would this differentiate mild steel from hardnable steel.
He said previously he had hung some similar and did some pistol target practice on them no distortion just a dimples where the round hit.
 
You'll be curious till you know...... So have a go and make a blade out of it.... Something relatively simple as a test...🤔
 
It is very unlikely that this material will be good for knives.

The density of all steel falls within a very narrow range.

If you want to recycle steel into knives, look for tooling, saws, shears, ball bearings etc…

It is good to have some steel like this around for other things.

Hoss
 
As said, just test it. Don't bother making a blade unless you just want the grinding practice. Cut a small piece around 1"X3", heat it nice 'n red, dunk in water. Than try to bend it. "IF" it's suitable for knife it should snap easy. If it bends, it's just low carbon steel. VERY handy to have around for odd stuff.

edit Jan 5th: When I said "suitable" I should have clarified a bit by saying it will make a knife that will work much like the old carbon steel case knives and butcher knifes of the 1940s and 1950s era with somewhere around 50Rc hardness. Not by any means a "great" knife steel by modern terms. See post below about a couple of sources for good knife steel. and don't heat to "bright red", that's too hot. Get a dull red as seen in a dim setting, using a magnet to test for non-magnetic.
 
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Ken H> said:
As said, just test it. Don't bother making a blade unless you just want the grinding practice. Cut a small piece around 1"X3", heat it nice 'n red, dunk in water. Than try to bend it. "IF" it's suitable for knife it should snap easy. If it bends, it's just low carbon steel. VERY handy to have around for odd stuff.
Click to expand...

Ken, since you are a friend I'm going to use your quote to myth-bust this.
It is a common quote on how to check is steel is "good for a knife". It isn't true. It might separate stainless steel from carbon steel, but many non-knife steels will snap like glass in this test. I've demonstrated this many times before.

To check it yourself, take a1"X3" bar of standard welding steel from HD, Lowe's, or any hardware store and heat it , heat it nice 'n red, dunk in water. It will snap just like the carbon steel we use for knives when you hit it with a hammer or give it a bend. Seriously, do it and see what happens.
Most folks are surprised it breaks. If the bar is close to zero carbon, it will bend, but it doesn't take as much carbon as you would think to make a brittle mixture of structures when untempered. Most welding steel and other mystery carbon steel has around .20-.25% carbon and hardens quite a bit when heated bright red and quenched in water. As-quenched it may be in the Rc50s. When tempered it drops drastically.
 
Stacy, While I do agree with you about just because the steel breaks doesn't make for a great knife, as you said it's can reach 50+ Rc in hardness. Just remember how many of the old carbon steel knives were manufactured in the 50 Rc range and are perfectly "acceptable" knives. For a "first" knife I still think it would be ok since the steel is on hand.

edit: I did a quick AI search and found this: "The Rockwell C (HRC) hardness of carbon steel knives made in the 1950s, such as certain Case knives, was typically in the high 40s on the Rockwell C scale, which corresponds to a spring temper. Historical analysis of Case CV steel from the 1950s indicates it was composed of 1095 steel with 0.50% chromium and 0.19% vanadium added, a formulation very close to W2 steel, and it was known for being easy to sharpen due to its hardness level."

I did not think it was that low. It seems like I've tested an old knife or two and found in the low 50 Rc range.
 
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Yes, that is why a snap test does not indicate good knife steel anymore. 1025 will snap if water quenched from bright red, but would make a poor knife.

The problem is that hardness is only part of what makes a steel suitable for a knife. Brittleness and toughness are the other issues. Glass is very hard but highly brittle and low toughness. Low grade steel may be tough in its normal state, but as-quenched is not going to last as a blade despite a hardness in the 45-50 range. It tempers to Rc 25-30.
 
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It's well known that RailRoad spikes are in the .025% to 0.30% carbon range. Even the RR spikes marked HC are only in the 0.35% carbon range. I've got a RailRoad spike (not HC) knife that's tempered and is in the 50 Rc range. Of course it was only tempered around 350°F, just enough to relax the steel some and not lower hardness much at all. That's also quenched in the "super Quench" https://www.lifesforge.com/superquench which seems to work pretty good.

I totally agree it doesn't make the "best" knives around, but they will get shaving sharp and hold an edge..... a little bit :)
 
I think you are missing my point.
I'm not saying that a low carbon streel won't make a knife. There are millions of them.
What I am saying is the old test of "heat to bright red and water quench, then bend, and if it snaps, it is good carbon steel" isn't an accurate indicator of suitable knife steel. Lots of steels will pass that test, but won't make a good knife.
 
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