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J.Leon_Szesny

Iron powder vs. Steel powder -what is it?!

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Hey,
So my question, is there any magical sciency way to tell whether something is steel or iron, if its in powder form?
I bought some "iron powder" but...is it really "iron" though? 
because if it is, im not sure it would be smart to use, since wrought iron welds at much higher temps than steel.

Im planning to mix this into my borax to make a welding flux that will hopefully help fill in any small gaps and valleys, from forging the two steels to forge weld. (I don't have access to tools for precision ground steel blanks)
So that's why im a little concerned about the actual metal this powder comes from.
Im planning to forge weld steel together at the lowest possible temperature and even though it is "powder" im concerned that if it's iron, that it might act as an obstruction.

or do you think it really wont matter since the grains are small enough to melt at low temps regardless of the carbon content?
borax does lower the melting point but I don't know.

ps:
hm forums section is about "heat treating?"
but it says "metallurgy,"  am I posting in the wrong place?

Edited by J.Leon_Szesny

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I think you are posting it in an OK location.  Hot Work or Beginner's Place would also probably be fine.  

Just a guess, but I would think your powder is steel, simply because getting it to be pure iron is more costly/difficult.  Could be wrong though, maybe you got lab grade iron.  There is also a chance it is cast iron powder.  Care to share where you got it and/or what the packaging says?  We may be able to help more with that.  

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the packaging was not much of help "eisen pulver 500g"(iron powder 1.1lbs) 
I got it from amazon and there its advertised as "something you mix into wall paint to make magnets stick to walls and or use in school for science or Physik"
so the first description doesn't help much but if its "for science," maybe that raises the chances of it being just iron.

here is the link
https://www.amazon.de/gp/product/B01GJIL9L0/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1

so far the only idea I could come up with is:
melt a little of the powder into a small billet and spark test it.

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The fact that its advertised for magnetic purposes is not helpful. That just means theres iron, that tells nothing about carbon content. So it could be iron, could be steel. 

Seems like a low price for lab grade iron. My bet is that its low carbon steel. 

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Yeah, sorry; I couldn't find anything to be more helpful.  

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Will,
I had a look around and did find some iron powders advertised as chemical symbol (Fe) which is pure iron
and those were not much more expensive than the stuff I bought.

Im starting to think I bought pure iron powder,
its no guarantee but all products called "iron powder," that had a description of a chemical symbols, said (Fe)
and I couldn't even find steel powder.

this makes me think that they purposefully make (Fe) powder for labs and don't even bother with making steel powder.
since maybe there's just no market and all the labs would probably have more interest in the pure element and not some alloy.

does that sound plausible/possible?
I would kind of prefer it to be steel but maybe seeing that the grains are literally dust, it wont effect the temperature at which it become weldable?

ps:
strangely enough I found a comment on one of the "iron powders" products, that was written by a german blacksmith who said he bought it to mix it with his flux...sadly he didn't say any more.
 

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It is most likely pure iron powder.  They make it by the ton for use in nutritional supplements and such.  It's done by electrolysis, much easier than grinding up big chunks.

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Why not post the question on the Amazon listing?  The seller should be able to tell you.

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Oh right, Iron can also be made for consumption, maybe I shouldn't forget that!
Iron deficiency is not fun or helpful, especially for artisans.

I already asked on amazon if it was (Fe) iron or just steel powder
the answer was: "yes" 
im assuming "yes" to it being pure iron?
 

Edited by J.Leon_Szesny

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FYI, here is a chemistry I received earlier this week for a few thousand pounds of iron cathode.  This is what I would refer to as "commercially pure" iron, or Ultra Low Carbon (ULC) block.  This material is going to be delivered in 0.25" thick squares, but I would think your sample is likely pretty similar if it isn't powdered steel or cast iron.  

image.png

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2 hours ago, Gerald Boggs said:

The answer you received was not from the seller.  It looks as if the seller hasn't answers any questions.

For those interested, here's the company I order from.

http://shop.chemicalstore.com/navigation/detail.asp?id=fe100.29

Interesting site!  I think this stuff would be ideal for blending with borax or boric acid in flux: http://shop.chemicalstore.com/navigation/detail.asp?MySessionID=262-468678537&CatID=21&id=CIRON150  5% carbon, 92% iron, 3%silicon.  

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Pleas explain why cast iron powder instead of the iron powder.  I use the iron powder with good results, if you mix it with powdered anhydrous borax, you gt the same mix as Swan or Iron Mountain, except not at $35 a bottle.

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The extra carbon lowers the melting point of the iron, so you get the powder in the flux going molten and hopefully making a happier bond with the high-carbon I'm usually trying to weld at a lower temperature than it might take otherwise.  This is assuming the borax is doing its job scavenging oxygen, otherwise the carbon would just go away as carbon monoxide.  

For instance, if I want to weld a billet of 1084 and 15n20, I really don't want to go hotter than around 2100 degrees F to avoid grain growth and carbon loss.  Pure iron doesn't go molten until around 2400 degrees, but cast iron (depending on carbon level) melts at anywhere from 1900-2100 degrees.  The theory is that the small amount of molten iron on the surface of the not-molten steel temporarily provides a layer of carbon-enriched steel with a lower welding temperature, thus allowing the solid-state diffusion bonding we call a forge weld to take place at a comfortable temperature for the high carbon steels.

I wouldn't go so far as to say it would work better on 1018 or wrought iron than plain iron powder in the flux.    I also wouldn't say it is necessary on high carbon.  If all it really does is enable the placebo effect to make welding seem more psychologically comfortable, that's fine with me. B)  As more than one smith has said, welding is all in the mind.  If you're afraid it won't work, it usually doesn't.  If a little magic powder gives you the confidence to make the weld, it's done its job whether or not it actually has any physical effect as a substance. 

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Alan, respectfully; I thought pure iron melted around 2700° (what I was told in welding class years ago) and I thought welding temp for low carbon was somewhere around 2300°-2400° or so? 

I just know I get it hot enough to bubble flux, make fumes, and sling it everywhere when I turn a 180 to the anvil. :lol:

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Pure is a pretty relative term.  The melting point drops pretty fast with a few stray elements.  And remember, the iron-carbon phase diagram only covers iron and carbon, there are a lot of elements in even "mild" or "low alloy" steel.  

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11 hours ago, Zeb Camper said:

Alan, respectfully; I thought pure iron melted around 2700° (what I was told in welding class years ago) and I thought welding temp for low carbon was somewhere around 2300°-2400° or so? 

I just know I get it hot enough to bubble flux, make fumes, and sling it everywhere when I turn a 180 to the anvil. :lol:

I just pulled those numbers out of thin air, you're probably right :lol:.  And I do the same thing, except I only turn 90.  I only use the thermocouple when heat treating.

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This is off topic, but is the primary reason for all the carbon in cast iron to reduce the melting point?

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49 minutes ago, Brian Dougherty said:

This is off topic, but is the primary reason for all the carbon in cast iron to reduce the melting point?

Historically I would think so, made things much more possible.  Now it isn't as critical, but definitely helps.  It also make the metal much more fluid, so casting fine detail is easier.  And it REALLY makes machining easier.  

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I thought it was more the case of we didn't know how to keep it out.

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I think it originally started as more or less an accident, pretty much a situation of "hey look at that, it melted the metal before the furnace".  Which came about with furnace design, air inlet angle, depths, etc.  

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I suspect it was just learning how to use what was initially an unwanted product.  The Chinese figured out cast iron for vessels over a thousand years before the Europeans did, but I don't know if they also invented the finery process to turn it to wrought iron.  I should really study ancient Chinese metallurgical history, but I'm busy enough with European...

Speaking of which, my understanding (and some experience) is that cast iron results from large-scale smelting in a shaft furnace.  Short-stack furnaces tend to produce wrought iron or a steely bloom depending on your ore and how hard you run them.  The taller the shaft or the lower the blast (this is a VAST oversimplification, but you get the idea), the more carbon the iron absorbs from the extra time in the reduction zone of the furnace.  When it gets over about 2% carbon, the melting point drops to below the heat of the stack and liquid iron then pools in the bottom of the furnace under the slag, which protects it from the oxidation that usually removes excess carbon from a bloom.  Prior to the 1300s this was considered a Very Bad Thing.  Somewhere in that time period (I'm writing this off the cuff, you can look up Stuckofen for the actual date) the Germans figured out that you can take this melted stuff that had no use and add slag while oxidizing it to remove carbon, and presto, what was a waste product becomes a labor-saving process.  Bigger furnaces tend to produce cast, so suddenly economies of scale came into play.  The realization it could be used to make cookware soon followed.  It wasn't until the 1700s that people figured out how cast structural stuff and cannons that wouldn't explode from it.

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1 hour ago, Alan Longmire said:

he Chinese figured out cast iron for vessels over a thousand years before the Europeans did, but I don't know if they also invented the finery process to turn it to wrought iron.

  "Out of the fiery furnace" talks about it.  If my memory serves, according to the author, the Chinese did the reverse of case hardening.  Cast tools and then remove the carbon from the outer layer.

Edited by Gerald Boggs

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