More 1084 weirdness

JTknives said:
I will say that it was quenched in parks 50 and agitated up and down till it stopped smoking and then between plates.
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I would try normalizing at 1650’ for 15 minutes then air cool followed by austenitizing at 1500 and parks 50 quench plus temper and see what happens.

Hoss
 
DevinT said:
I would try normalizing at 1650’ for 15 minutes then air cool followed by austenitizing at 1500 and parks 50 quench plus temper and see what happens.

Hoss
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That’s about exactly what I did. But I think I was at 1600° not 1650°
 
Were the blades wrapped individually in foil when normalizing or one envelope for all the blades at once? If they cooled slowly as a group, it would be an anneal more than a normalize.

Just wondering if austenitizing after a pearlite structure was reached instead of ferrite would make a difference?

Hoss
 
It all boils down to: is something wrong with the steel, or something wrong with the JT show?

I told a materials scientist-type friend of mine about this, and he immediately said, "It's [the hardness] is banded? The top or bottom of a melt got used. It happens." That's what I think, bad part of a melt got rolled, or the melt cooled off too slowly and there was separation of elements, or more likely, not hot enough long enough. In short:

Don Hanson III said:
It's just a bad piece of steel.
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All the mass spectrometry in the world is, ultimately, just going to confirm the above in more detail. Unless the diminishing prospect that it's all JT's fault after all gets proven somehow.

Another point: when people new to knifemaking ask about what steel to use they are often told to use 1084 for various reasons, all related to the relative ease of using it, which could also be expressed as, "it's harder to fuck up." It also means that 1084 would be easier to pass along with more impurities or outright bad/counterfeit steel (talking about EBAY here), unless it gets sent to someone like JT who knows the difference and has the tools to test it. How many people used the same batch of "1084" to make some knives and never even knew anything was wrong with it? More than one, I bet.
 
Mecha said:
It all boils down to: is something wrong with the steel, or something wrong with the JT show?

I told a materials scientist-type friend of mine about this, and he immediately said, "It's [the hardness] is banded? The top or bottom of a melt got used. It happens." That's what I think, bad part of a melt got rolled, or the melt cooled off too slowly and there was separation of elements, or more likely, not hot enough long enough. In short:



All the mass spectrometry in the world is, ultimately, just going to confirm the above in more detail. Unless the diminishing prospect that it's all JT's fault after all gets proven somehow.

Another point: when people new to knifemaking ask about what steel to use they are often told to use 1084 for various reasons, all related to the relative ease of using it, which could also be expressed as, "it's harder to fuck up." It also means that 1084 would be easier to pass along with more impurities or outright bad/counterfeit steel (talking about EBAY here), unless it gets sent to someone like JT who knows the difference and has the tools to test it. How many people used the same batch of "1084" to make some knives and never even knew anything was wrong with it? More than one, I bet.
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All that said, I still want to see what happens when it gets normalized again and whatnot. :D
 
I've been following along with the thread and I may have missed it if it was mentioned, but where was this particular steel purchased from? Was it from ebay, or from NJSB?

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)
 
coldsteelburns said:
I've been following along with the thread and I may have missed it if it was mentioned, but where was this particular steel purchased from? Was it from ebay, or from NJSB?

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)
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In the last "bad 1084" thread, the steel was thought to be from NJSB but it turned out that the person who sent it to JT had mixed up steel and used the wrong stuff.

The only thing anyone knows for sure about it is that someone obtained steel, had a knife blank laser-cut from it, and that blank got sent to JT for heat treatment where a problem surfaced. The piece of steel barely even got touched before arriving at the heat treater.
 
Folks - just exchanged email with my chemical analysis contact. She seems interested (she and I have been shoulder to should in the past in solving many technical mysteries - and she loves a good puzzle). the question is timing and resources ... stay tuned.

JT - she (as I expected) asked the size of the blade. I told her I expected there would not be a big problem is cutting the blade to a size small enough to fit her electron microscope chamber (something like 6 inches as I recall). Hopefully that is the case????
 
Cycle it high (1700), run a couple reduction cycles and reharden. Could be the "curse of coarse spheriodite".

Also.... I couldn't help but notice that the weird perpendicular banding after the surface grind, looked awfully similar to your magnetic table pattern.
 
Rick - that is a really good observation .. but (sorry), a guestion would be what is the likelihood that the magnetic table had such a full- width effect onthe material as to so strongly effect the phase of the material across the entire width? Also, the banding was seen prior to exposure to the magnetic table? Again,this is a cool observation, but i am asking if it is consistent with the sequence of observed data?
 
Cushing H. said:
Again,this is a cool observation, but i am asking if it is consistent with the sequence of observed data?
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I didn't mean to say it had something to do with any of the metallurgical issues. I think it just affected the surface grinding finish. JT, mentioned the banding, as if it was an artifact of the heat treat. I don't feel it had any correlation.

Just to qualify my statement a bit. I was flattening a blank on my 2x72 platen, using a 50lb pick-up magnet to hold onto it. I couldn't for the life of me, take out these two long bands... until I realized it was because of the magnet. I took it off and used a rest instead... bingo.
 
Rick Marchand said:
I didn't mean to say it had something to do with any of the metallurgical issues. I think it just affected the surface grinding finish. JT, mentioned the banding, as if it was an artifact of the heat treat. I don't feel it had any correlation.

Just to qualify my statement a bit. I was flattening a blank on my 2x72 platen, using a 50lb pick-up magnet to hold onto it. I couldn't for the life of me, take out these two long bands... until I realized it was because of the magnet. I took it off and used a rest instead... bingo.
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So does that mean orienting a blade north-south while quenching really DOES affect the ht? o_O
 
Rick Marchand said:
Cycle it high (1700), run a couple reduction cycles and reharden. Could be the "curse of coarse spheriodite".

Also.... I couldn't help but notice that the weird perpendicular banding after the surface grind, looked awfully similar to your magnetic table pattern.
Click to expand...

I was kind of wondering how often this type of thing presents with a forged blade. It seems to be always stock removal blades.
 
So I recently bought a couple of bars of 1084. It is steel from Canadian Knifemaker Supply and they get their stock from NJSB. Should I exchange for some 1080 or what?
 
I
Rick Marchand said:
I didn't mean to say it had something to do with any of the metallurgical issues. I think it just affected the surface grinding finish. JT, mentioned the banding, as if it was an artifact of the heat treat. I don't feel it had any correlation.

Just to qualify my statement a bit. I was flattening a blank on my 2x72 platen, using a 50lb pick-up magnet to hold onto it. I couldn't for the life of me, take out these two long bands... until I realized it was because of the magnet. I took it off and used a rest instead... bingo.
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Agree Rick, those straight lines showing in the etch pic are not banding.
 
JT - I head more back from my contact - and though they are pretty busy, one of the members of the group (whom I also know) is interested and willing to take a shot at this analysis. I am waiting to hear back for a preferred (really maximum) sample dimension - but I am hoping that we can get a sample big enough to cover, say, 3 of your significantly different hardness measurements. I will get back when I hear something definitive on dimensions.
(this may take a while with their work load and the holidays coming up ... but it looks like we can get this done)
 
JT - left a message at work, but not sure if you are picking up. Pls call me about chem analysis? 612-812-8764
 
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