Thread: Blacksmith Fact or Fiction

Hi

Originally Posted by thumbsucker

I was wondering if you wise metalworker could enlighten me. I have been by accident reading allot about blacksmithing and tool making. I came across an interesting claim. The claim is that a cutting tool beaten into shape by a blacksmith will have more carbon compressed into a smaller space then if the cutting tool formed by other means. The idea being that the carbon is what gives the tool its cutting edge and by smashing the steel you will have more of cutting carbon in one place.

This is why old tools are better then modern machined tools or so the advertising says.

Blacksmithing is really a lost art. I imagine that many years ago some blacksmithing methods were discovered by accident and maybe in the more recent past (prior to the slow demise of the blacksmith) other methods were discovered by "intelligent" experiments.

Essentially anything forged (and perhaps cast) tends to be stronger and more durable. This is partly due to the "grain" (as mentioned in another message in this thread).

Metal certainly has grain, though not quite in the same observable manner as you can clearly see in timber, nevertheless the grain IS there.

When metal is forged or cast the grain in the metal is coerced to flow within the direction(s) of the item. In so doing the structure and the strength of the item is improved.

As has been noted before, if you have an item such as a knife and the process of creating the edge involves the removal of the granular structure of the meta, then the edge will not retain its sharpness as well as a knife that has been forged.

The graininess of the metal at a molecular level of a forged blade is "tighter" or more closely bound so the removal of metal to create the sharp edge does not weaken the bond between the molecules as much as can happen with a blade that is ground to shape. The grain direction/flow will have been broken in a knife that has been cut or ground to shape.

If you take for example, an old (metal) file and grind it into a knife it will NOT be as strong or be able to retain its edge as well when compared to taking that same file and forge it into the knife shape before sharpening.

Cast iron or other cast items have superior strength due to the "natural" flow of the grain as the casting material flows around the mould/mold.

There is probably more blacksmithing information lost in oblivion than remains in general knowledge today.

BTW. Did you know that you can magnetize an iron rod or some steels by aligning it with the earths magnetic field and hitting one end. (geez, it's been years since I did that )

Originally Posted by MrFixIt

The graininess of the metal at a molecular level of a forged blade is "tighter" or more closely bound so the removal of metal to create the sharp edge does not weaken the bond between the molecules as much as can happen with a blade that is ground to shape. The grain direction/flow will have been broken in a knife that has been cut or ground to shape.

What exactly are you trying to say here, forged metal is denser? Or somehow forging is increasing the strength of the metallic bonds? Also there are no 'molecules' in metal - metals have an crystal lattice held together with ionic bonds.

I think the original proposition is probably one of those occasions where a layman has come up with a thoroughly plausible explanation for an observation and over time this has been turned into a 'fact'. It smells a little bit too much like an attempt to create a mystique about the art of blacksmithing rather than explain what is happening using science.

I think there are several potential possibilities:

1. Some sort of case hardening effect
2. Granular structure
3. I love the idea raised by son_of_bluegrass that all the old junk tools have been thrown out, so now as we look at the surviving best of the best old tools, we come to the false conclusion that 'old is better'.

It would be great to get a metalugists perspective.

Originally Posted by MrFixIt

BTW. Did you know that you can magnetize an iron rod or some steels by aligning it with the earths magnetic field and hitting one end. (geez, it's been years since I did that )

Pipe welders in refineries know it very well. The magnetic effect comes about from the pipe (aligned in a north south axis ) vibrating across the east west beams.

When a worn section is cut out and replaced with a new bit, magnetics cause major welding problems.

Grahame

Originally Posted by MrFixIt

BTW. Did you know that you can magnetize an iron rod or some steels by aligning it with the earths magnetic field and hitting one end. (geez, it's been years since I did that )

I have a friend who's a tattoo artist in LA, a brit. He told me about a well known manufacturer of tattoo machines (the frame that holds the vibrating needle part) , an individual, who as part of the production process buries the cast blanks in his backyard for several years, supposedly aligning them in some way magnetically. I don't know if he meant with the Earth, or just all the metal is magnetically aligned.

This in turn is reputed to produce a tattoo that heals more quickly. I was tattoo'ed with one and did indeed heal faster than tattoos I received elsewhere, but of course it could be no more than a great story, I'm just passing it on.

Originally Posted by browny

Also there are no 'molecules' in metal - metals have an crystal lattice held together with ionic bonds.

Ionic Bonds are bonds between a metal and a non-metallic elemsnt. Metals are held together by Metallic Bonds. These bonds are responsible for the ductility or malleability of metals.

For most metals there is an intermediate micron grain size structure as well. It's a bit (only a bit!) like ice crystals. if you can freeze water evenly and slowly you can make large ice crystals, if you do it fast you get a whole lot of small crystals. If you continually tap a container full of water during freezing even slowly you will still create small grains. Metal grains are held together by a complex mix of electrostatic forces. Heat treatment and additional elements alters the grain size and compositional structure of grains and intergrain components which are the major deciders in the properties of the metal including how hard it is and how well it will hold an edge etc. In short the grains have a major role. Beating while cooling supposedly creates a grain structure and orientation and alignment that support what is desirable in carbon steel cutting blades. What has happened in the last 100 years is obtaining the properties we desire in steel by replacing the beating of carbon steel, by using chemistry by creating different alloy or tool steels.

That's just a simple hand waving web style description. To really understand this across in depth needs second year maths, and solid state physics at about 4th year uni level through equations like . . . . .- nah let's not go there.

Hello Thumbsucker

I completed an apprenticeship as a blacksmith a long time ago but did not continue to work in this field but this is what I recall of the matter.

In your first question I wonder if the metal you were reading about was wrought iron which was eventually replaced by steel. If this is the case then the statement may be based on fact as in wrought iron the carbon & iron were like seperate strings of grain and this material improved as it worked & the more it was worked the more the two elements required for hardening to occur were more evenly combined. Hardening occurs when heat is applied causing these 2 elements to go through chemical changes & when cooled the material is trapped at a certain stage

As for question 2: in steel the 2 elements are evenly distributed together the it is the amount of carbon in a steel that controls how hard it will become. The problem with making steel hard is the harder it gets the more brittle it gets so something like a cold chisel needs a good balance of hardness & toughness or lack of brittleness. The best cold chisels I made were from old track pins which were about .75% carbon.

We studied metalurgy at a very basic level but did our assessment of carbon content of unknown steels by the sparks produced from grinding.

Crickeys most I've ever said on this forum. Hope it helps.

Ray

Another rant

The only "packing" we did was to case harden material by packing it in a metal case with very carbon rich material & soak it in a furnace for hours. This would produce a carbon rich outer casing but this was measured in thousands of an inch after hours of soaking so the theory of the steel picking up sufficient carbon, during heating in the forge, to make any noticeable difference is extemely unlikely.

Ray

Think of the difference between forged and ground steelwork as pretty much like the difference between a carefully selected a piece of wood verses any old chunk off the woodpile.

If you select a piece for say, a highly curved chair back, and you select a timber with grain matching the desired curve, you'll get a stronger finished piece. That's your equivalent of forging.

If you grab any old block of wood and bandsaw your curve into it, it's more than likely you'll end up with sections of really short grain which will break much more easily. That's your equivalent of grinding.

You could probably expand this simile somewhat; cooling the metal quickly is like choosing an ironbark as your seedling to grow your chair back from; cooling it slowly is like choosing a pine seedling.

But with metal you get to be really clever - it's like being able to get your tree stock specially grafted so that you have bits of pine where you need it easily workable, and ironbark where you need strength.

When you are forging steel, you are refining the grain structure and forcing it flow in the direction you want. This flow, combined with creating the right grain (a martensic structure for hardness, created by a combination of temperature and the amount of carbon), helps give the steel its qualities.

Metals are held together (strangely enough) with what is called a metallic bond - electrons are not held tightly to each atom, instead it's more like the atoms are in a 'sea' of electrons (this is why metals conduct electricity and heat so well) and this electron sea means that the atoms, too, have great freedom to move.

This freedom is why you can bend metal so much - the lattice happily re-arranges itself without damage.

The weak point in the lattice structure is the endpoints of the lattice - the grain boundaries; this is where we go from one electron sea to another (they are rubbing coastlines with each other, if you like).

Grain boundaries are where all metal failures occur; if you can do something to improve the way grain boundaries hold onto each other, you can increase the strength of the steel.

When you add different atoms to iron - such as carbon - you can get the iron to form particular lattice structures (martensite) which act like dowels and help lock grain boundaries together; if you add atoms such as sulphur, this acts like a goodly spray of silicone, and no amount of glue is going to get those boundaries to stick!


(or if you prefer fish examples rather than wood ones, try here - http://swordforum.com/metallurgy/ites.html )

yaryetnom and Master Splinter thank you for your simple wood explanations. I think that the answer is not simple and blacksmithing is art as much as science. I think this is a thing that I would have to see for myself, making different things adding carbon, packing, forming grain learning how it goes.

Originally Posted by thumbsucker

I think that the answer is not simple and blacksmithing is art as much as science.

Thats where I kind of disagree. The creative aspect is undoubtedly art. The metallugical aspect is materials science.

It ????? me when the science aspect of something is touted as 'art' to create the illusion of mystique.

Originally Posted by BobL

Ionic Bonds are bonds between a metal and a non-metallic elemsnt. Metals are held together by Metallic Bonds. These bonds are responsible for the ductility or malleability of metals.

That's just a simple hand waving web style description. To really understand this across in depth needs second year maths, and solid state physics at about 4th year uni level through equations like . . . . .- nah let's not go there.

I totally agree that your hand waving description is much better than mine. I was struggling to come up with something really short really quickly, and it shows.

I believe the trade is a combination of science & art/skill. Without an understanding of the science of why metal behaves as it does a blacksmith would struggle to carry their trade. However, when working with a forge they all behave slightly different & the temperatures required for different processes is based on the science but interpreting the temperatures is based on art.

I guess its no different do doing any other trade that requires manual skills & a feel for how things happens.

I know there are a lot a myths out there & have had peope swear they have seen an old blacksmith somewhere do things you know are just not possible.

Ray

Where is the residential expert artemis when you need him?

This site may hold some answers to questions posed above.

http://www.iforgeiron.com/blueprints...-treating.html