Steel Identification

A

A.j.young

Joined
Dec 8, 2018
Messages
3
Hi,
Our Rendering plant in a large meat processing plant uses a hammer mill to break down bone and product after it is cooked to produce meat meal and such. Hammers in the hammer mill get replaced often then thrown out when worn. I tested one of the hammers that was 60HRC on my tester, that surprised me as I would have thought this was quite high for the shock these are taking. I decided to send a sample away for chemical testing to identify, with the thought of a good supply of steel if suitable for forging knives. Test came back with the following that I am having trouble finding an equivalent? C 0.69, Si 0.22, Mn 1.50, S 0.008, P 0.008, Cr 0.09, Mo 0.11, Cu 0.23, V 0.04, Ni 0.08, Nb<0.01, Ti 0.04
 
A.j.young said:
Hi,
Our Rendering plant in a large meat processing plant uses a hammer mill to break down bone and product after it is cooked to produce meat meal and such. Hammers in the hammer mill get replaced often then thrown out when worn. I tested one of the hammers that was 60HRC on my tester, that surprised me as I would have thought this was quite high for the shock these are taking. I decided to send a sample away for chemical testing to identify, with the thought of a good supply of steel if suitable for forging knives. Test came back with the following that I am having trouble finding an equivalent? C 0.69, Si 0.22, Mn 1.50, S 0.008, P 0.008, Cr 0.09, Mo 0.11, Cu 0.23, V 0.04, Ni 0.08, Nb<0.01, Ti 0.04
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That just looks like a basic carbon steel like 1070 or similar
 
steel made from recycled materials will often have the things listed like copper , nickel and less often titanium. Stuff like lead and cadmium will also get in occasionally too. People often see a test sheet like the above and will assume the things are in the steel on purpose. Steels for certain products like submarine hulls or reactor vessels have to meet requirements and wouldn't be able to use steels like that and are tightly controlled and certified during all parts of the process but a bone hammer in a rending plant probably only has to meet a few requirements.
 
A.j.young said:
I tested one of the hammers that was 60HRC on my tester, that surprised me as I would have thought this was quite high for the shock these are taking.
Click to expand...

You're just testing the surface hardness. Probably not hardened all the way through like a knife blade is.
 
I will need to grind a sample and test the depth of hardness. I would be surprised if it is surface hardened as they would have rapid wear once the surface is worn away, and it doesn't appear to be the case. As for wear resistance I would of thought this material would have a high resistance, more than a simple 1070? Perhaps the higher Mn is providing a higher carbide content to help with wear resistance?
 
Larrin said:
With the relatively high Mn it might be oil quenched for through-hardness.
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Might be, but why? Case hardening by induction heating (the composition has enough C for that) is (comparatively) quick & cheap, and having the "inside" of a hammer softer & tougher sounds like a plus - unless the hammer force is such that you'd get significant elastic or even plastic deformation.

From Wikipedia (emphasis mine):

Parts that are subject to high pressures and sharp impacts are still commonly case-hardened. Examples include firing pins and rifle bolt faces, or engine camshafts. In these cases, the surfaces requiring the hardness may be hardened selectively, leaving the bulk of the part in its original tough state.

So, like a hammer.
 
A.j.young said:
I will need to grind a sample and test the depth of hardness. I would be surprised if it is surface hardened as they would have rapid wear once the surface is worn away, and it doesn't appear to be the case. As for wear resistance I would of thought this material would have a high resistance, more than a simple 1070? Perhaps the higher Mn is providing a higher carbide content to help with wear resistance?
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Mn doesn't form carbides. The only element of note that would cause significant carbides to form is the iron. And 0.7% carbon isn't a high amount. If anything the Mn might be detrimental in that volume.
 
Great, appreciate the input nothing too special here then. No need to waste too much time on this stuff. Plenty of other "junk" steel of better quality if I feel the need. Railway clips here in Australia are siad to be 1080, and a power hammer in my shed. If I'm ever short on steel...
 
A.j.young said:
Great, appreciate the input nothing too special here then. No need to waste too much time on this stuff. Plenty of other "junk" steel of better quality if I feel the need. Railway clips here in Australia are siad to be 1080, and a power hammer in my shed. If I'm ever short on steel...
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You could always just try.one... Make a knife see how it is!🤔😱😳
 
Definitely wouldn't get too wrapped up in all the trace elements present. For heavy use industrial purposes, it is most likely cast from a simple 1070 type carbon steel recipe, with all those <1% elements simply picking up left overs from the build up inside the crucible(s) when pouring.

From my previous experience in an investment casting foundry, where we made many different industrial products en masse, the types of products that are made to be used and worn, then disposed and replaced, as long as you were hitting the main marks (carbon & iron, chromium for stainless, silicone as a deoxidizer, etc., crucibles were reused from batch to batch to batch, and absolutely if we just did a batch of say 440 or even D2, then went on to pouring a 1075 or whatever, trace elements would still be present and picked up during the pouring process. Such is the case for many if not most cost effective consumable industrial steels that don't require specific tight tolerances and/or the specific benefits of powder processes which also cost far more. (Like hammers for a hammer mill).

However, because of those trace elements present, hell, you might by an off chance have a slightly better version of 1070 by pure happenstance. I remember reading that viking swords, in a similar fashion, earned their reputation of being "better steel", because of the impure iron often found in the ore of their mining regions which was laced with other trace elements, even though they were completely unaware of the science, they were in fact producing "better" (micro-alloyed) steel... I don't don't know just how true that information was, but if they had trace chromium and vanadium and nickle and whatever else in their iron, and produced it virtually the same way, I could certainly see it gaining a slight edge in performance (no pun intended), over steel from the same era being produced from pure iron...
 
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