Silver Steel, Carbon, stainless

An interesting thing I thought I would share about razors made with different steels.

Iron is the base mineral for all types of steel.

Carbon Steel

• Steel is made by mixing molten iron with carbon. Fine carbon powder is mixed in with the molten iron; the carbon molecules chemically fuse with the iron molecules to create steel. Picture a hacksaw cutting an iron pipe: The hacksaw blade is high-carbon steel, while the pipe is low-carbon steel. The hacksaw blade cuts the pipe because it's steel is harder. Interesting fact about carbon steel is before modern methods of using pressurized gases, high carbon steel were made by
  heating the iron red hot and rolling it in any type of plant matter. The plant matter would burn and leave a residue of carbon and then the iron would be folded and hammered binding the carbon molecules to the iron. The katana and samurai sword was made this way sometimes being folded over up to 30,000 times.
  
  Silver Steel:
  
  
  

Razors made with silver steel means it has 0.02 percent real silver mixed into the steel alloy. It may not seem like much, but that two hundredth of a percent of silver changes the composition enough for the steel to easily take a mirror finish. Tool steel is often a type of silver steel.

Blued Steel

• Steel's main component, iron, is prone to rust -- and bluing is a chemical treatment of the steel's surface to prevent rust. For example, since firearms are used outdoors, bluing is applied to all exposed steel parts. The bluing process involves using various chemicals that etch into and color the steel, according to Rand Esser, metals patina specialist at the University of Wyoming.
  
  

Stainless steel

Stainless steel is a steel alloy composed of iron, carbon, and chromium (chrome). Usually stainless steel has a Chromium content of 10.5% to 11%, which makes the steel more resistant to rust.

Carbon steel and Stainless steel:

Even simple steels with higher carbon content, e.g. AISI 1095 can be hardened to much higher levels compared to mainstream stainless alloys, at those levels stainless steel becomes too brittle. Edge holding, especially on soft materials is better at high hardness, i.e. carbon steel will have the advantage.
Obviously, exotic stainless PM alloys like ZDP-189 or Cowry-X are exception, but in general, average stainless steel used knives can't be hardened as high.
For the same reason(lack of toughness), stainless steel is almost never a good choice for large knives. It either has to be too soft to have enough toughness, or compromise its strength to have better edge holding ability.
Edge holding of the stainless steel might be better compared to simple carbon steel alloys at lower hardness, due to Chromium Carbides in stainless steels, but carbon, or non-stainless steels with other alloying elements such as Vanadium, Tungsten, Niobium(Columbium) have much harder carbides than Chromium forms. Their edge holding is a lot better compared to most of the stainless steels.

Several of the points you discuss beg to be refuted. I'll take on two since I'm trying to get ready to teach this stuff tomorrow. I wish you could be here.

Katana, made in Japan, are forged from tamahagane built into a billet of oroshigane then forge welded. No sword has ever been folded 30K times. The carbon content of tamahagane is 1.4-1.6% as smelted. By the time the billet has been forged into a blade the carbon content is reduced to between 0.6-0.7% depending on the particular sword school the smith attended. Forging a katana does not add carbon into the steel.

This does not mean that the smith does not understand how to add carbon to low carbon irons. The techniques to add carbon to irons are several. Attempting to add carbon from organic ashes is considerably less efficient than simple adjustment of the atmosphere of the forge and taking the time to allow the carbon to diffuse into the iron and considerably less efficient than packing the iron in a closed atmosphere box containing sources of carbon and preventing the carbon from binding to oxygen, its preference to iron.

The rest of the essay needs as much work. At least give eHow credit for most of your citations.

I wasn't saying that folding steel magically makes carbon appear. They would get the steel red hot and roll it in dried plant fibers (like hay) and it burns leaving carbon residue, then they fold the steel over to jam the carbon molecules into the steel (then repeat). I seen a video on how they used to make those swords on nat geo. If you want to refute where I got my facts you can do so, wasn't trying to hurt but inform basic differences in razors made with different steels.

Mike Blue is the expert in the metallurgical field around these parts. I am certainly not but, referring to a different topic in the OP, I'm under the impression that stainless is abrasion resistant. One of the characteristics, if I understand it correctly, that can sometimes make it a bit more difficult to hone to a shaving sharp edge, than high carbon steel. IME stainless straight razors are mighty good to shave with and not that bad to hone with the exception of a few more exotic steels I've come across. Just IMHO.

You only need 15 folds to get ~32000 layers. Every fold doubles the number. So based on that, it doesn't seem so far-fetched. Mike, is it possible for the smith to fold the sword steel 15 times? That would explain where that particular bit of broken telephone information happens.

looks like xMackx got his number of layers and number of folds mistaken. If the steel is folded 30000, you'd get 2 to the power of 30000 - Wolfram|Alpha layers. I'm no metallurgy expert but I believe at that point, there will be no more layers as they will all fused.

Just a few points that are in need of refinement:

For our purposes - straight razors, not japanese swords - the steel process varied, but traditionally was a carburisation or de-carburisation process (ie adding or subtracting carbon). In the early days of Sheffield's rise to fame, 'blister steel' was used. This was made by packing iron bars tightly in a box with layers of charcoal in between and heating for a prolonged period. The result was the absorption of carbon, giving the bars a blistered look. The process mainly affected the outer surface of the iron and diffused out as the centre was approached, so it was beaten in an attempt to equally mix the carbon. This process was adopted because Sheffield imported vast quantities of Swedish ore and iron, which is very pure and thus has a very low carbon content. After hammer-forging bundles of blister-steel rods together a higher-quality steel was formed - Shear Steel. After Huntsman re-discovered the crucible (or cast steel) process, he used blister-steel broken into pieces and melted in crucibles - this gave a more even spread of carbon throughout the body of the steel.

With regard to silver steel, the original alloy did indeed contain a small percentage of silver and was the result of James Stoddard's and Michael Faraday's experiments into various alloys of steel, prompted by investigating the old indian Wootz steel. Silver steel caught on for a while, and was used by several razor-makers, eventually the process was bought and the product re-named Peruvian Steel - still containing silver. The use of such an alloy in the razor-world was short-lived though. From its invention in 1824 it was popular for a decade or so. The name 'Silver Steel' was retained for another high-carbon tool-steel alloy with a bright reflectance, but the silver was not. Since those early days silver steel has contained no silver at all.

Bluing does not prevent rust as it is essentially a 'passive' process that makes steel less likely to rust by encouraging one form of rust (the black type) over another (the red type). However, it will fail if the blued surface is not treated with an appropriate oil. Modern bluing is an electrochemical process, but it did not begin that way. The original rust-bluing involved letting a very fine coat of rust cover the article to be blued, encouraged by hanging the article in a humid atmosphere, sometimes with corrosive fumes in it (from an open bowl of acid or similar). The fine layer of rust was 'carded off' (brushed off with a fine wire brush) and the process repeated. It gave a fine, plummy brown non-reflective layer - eventually - that resisted rust well after application of oil. The colour could be modified by boiling to give a darker colour. This process gave way to hot-salt-bluing (a mix of dangerous chemicals was used, sometimes with cyanide) and the electro-chemical process - carding and repeat operations were still used for some of these processes. The cold-bluing processes are not really true bluing, and have very little resistance to wear compared to the other techniques.

Regards,
Neil

Neil, very good monograph.:)

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Originally Posted by xMackx

I wasn't saying that folding steel magically makes carbon appear. They would get the steel red hot and roll it in dried plant fibers (like hay) and it burns leaving carbon residue, then they fold the steel over to jam the carbon molecules into the steel (then repeat). I seen a video on how they used to make those swords on nat geo. If you want to refute where I got my facts you can do so, wasn't trying to hurt but inform basic differences in razors made with different steels.

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The reason for the folding the katana steel is to evenly distribute the carbon in the steel, as well as making the steel much stronger by adding layer structure.
Silver steel does not contain silver it is just the name of a certain carbon tool steel :
Silver steel - Wikipedia, the free encyclopedia
Silver Steel
If you think of the properties steel has to have what good does silver do in the steel?
The main component is carbon, then metals like tungsten/vanadium/molybdenum are added to make the steel more wear resistant, or more rust resistant etc. Silver does not add any useful property to carbon steel.

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Originally Posted by mainaman

The reason for the folding the katana steel is to evenly distribute the carbon in the steel, as well as making the steel much stronger by adding layer structure.
Silver steel does not contain silver it is just the name of a certain carbon tool steel :
Silver steel - Wikipedia, the free encyclopedia
Silver Steel
If you think of the properties steel has to have what good does silver do in the steel?
The main component is carbon, then metals like tungsten/vanadium/molybdenum are added to make the steel more wear resistant, or more rust resistant etc. Silver does not add any useful property to carbon steel.

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Very true, unfortunately!

Faraday's main concern was to find a form of steel less susceptible to corrosion. However, extensive tests performed on the ingots left by Faraday at the Royal Society by the eminent Sir Robert Hadfield in 1931 and on a knife and razor blank proved that in terms of corrosion resistance, silver steel differed but little from ordinary carbon steel.

His series of experiments on alloying steel (he added gold, platinum, rhodium, copper, manganese, nickel and more) led to the widespread adoption of alloy steels, so we owe him a great deal. The experiments began by James Stodart (sometimes spelled Stoddard) who was senior to Faraday and a Fellow of the Royal Society before Faraday commenced with making Wootz, but with Faraday's collaboration (he was not allowed to address the Society before being a fellow of it) and further insights it embraced other alloys and continued after Stodart's death in 1823.

Regards,
Neil

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Originally Posted by xMackx

I wasn't saying that folding steel magically makes carbon appear. They would get the steel red hot and roll it in dried plant fibers (like hay) and it burns leaving carbon residue, then they fold the steel over to jam the carbon molecules into the steel (then repeat). I seen a video on how they used to make those swords on nat geo. If you want to refute where I got my facts you can do so, wasn't trying to hurt but inform basic differences in razors made with different steels.

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I know that you're not trying to hurt anything. It's easy to watch a show and the first time you observe a process and think one thing might be going on, when in fact, something else is happening. These subjects have been worked over fairly well on this site. I've watched all those shows. While NatGeo has a good reputation, and I enjoy watching my friends demonstrate on TV, the producers often err about things that make those who know about the process cringe.

It's no different than the source of many legends about steels. They are magical stories because at the time (pretty much any time before the early history of real chemistry) that's the best way to understand what the smith was doing. Knowledge about what's going on inside that bar of steel is considerably better now.

30,000 Layers, or more depending on the starting layer count, is very possible in 15 folds. The death of the idea that 30,000 Folds happens is the simple fact that scale formation would burn away all the steel you started with long before any useful object resulted from the work.

Okay, I ran out to the shop and Spazola and I just measured a piece of scale from the floor by the big hammer. I specifically use methods to reduce scale formation so we're already discussing a variable that may not hold true for other shops. This also means that in my shop this is a conservative estimate of scale loss. The pieces of scale measured in the caliper average 0.005 inch thick.

Now, scale loss is a four sided effect on a billet. To be even more conservative, we only calculated the scale loss from two sides of the billet, the sides that will be exposed to the atmosphere, not the side between slabs being welded and not the sides that are not (which would double the amount of scale). 2 x 0.005 inch = 0.010 inch x 30,000 = 300 inches of material loss by the time you get to 30000 folds. All of us here today think the math is correct, but if it's not I'll agree to a change in the answer. And that's only two sides. It will go faster adding the remaining two sides in, or adding in less controlled forge operations/processes.

A 300 inch thick piece of steel is much more than I could lift, and I don't have a forge big enough to hold it. A 1.18 diameter bar 12 inches long weighs 4.8 pounds. Multiplied by 300 that's 1200 pounds roughly.

In the end, much better information produces less myth and magic. It also takes time to accumulate.

It's not 30000 folds, it's 30000 layers which is done by only a handful of folds. There are numerous sources that document this is what is actually going on in a katana. I'm not a metallurgist by any means but I've had an interest in ancient Japan for the past 25 years and I've read this hundreds of times in hundreds of sources. Now if only I could afford to spend what it would take to purchase a truly antique Japanese sword. I've always wanted one but $2500+ for a wallhanger will never happen in my life.

I balieve the number of folds is 16 which means 65000 and some change layers for katana.
Recently one of the knife makers over at the Knife forums did 1 million layers, pretty cool stuff.
1 MILLION layer damascus billet!!

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Originally Posted by mainaman

I balieve the number of folds is 16 which means 65000 and some change layers for katana. Recently one of the knife makers over at the Knife forums did 1 million layers, pretty cool stuff.

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The way he did that billet was to single weld 25 layers and then 7 welds where he cut and stacked by four pieces at a time. It was only eight welds and over a million layers. Starting with a higher layer count makes things go a lot faster. I would have like to see pictures of that billet after it was ground down into to form a bevel. I think it's interesting to see how much the 15N20 takes over the appearance.

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Originally Posted by Mike Blue

The way he did that billet was to single weld 25 layers and then 7 welds where he cut and stacked by four pieces at a time. It was only eight welds and over a million layers. Starting with a higher layer count makes things go a lot faster. I would have like to see pictures of that billet after it was ground down into to form a bevel. I think it's interesting to see how much the 15N20 takes over the appearance.

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Mike,
someone bought the billet and they are making him a knife out of it, I am sure there will be a WIP thread about it.
Those guys also did a meteorite Damaskus WIP thread , the resulting knife was really something.

Quote:

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Originally Posted by Mike Blue

I know that you're not trying to hurt anything. It's easy to watch a show and the first time you observe a process and think one thing might be going on, when in fact, something else is happening. These subjects have been worked over fairly well on this site. I've watched all those shows. While NatGeo has a good reputation, and I enjoy watching my friends demonstrate on TV, the producers often err about things that make those who know about the process cringe.

It's no different than the source of many legends about steels. They are magical stories because at the time (pretty much any time before the early history of real chemistry) that's the best way to understand what the smith was doing. Knowledge about what's going on inside that bar of steel is considerably better now.

30,000 Layers, or more depending on the starting layer count, is very possible in 15 folds. The death of the idea that 30,000 Folds happens is the simple fact that scale formation would burn away all the steel you started with long before any useful object resulted from the work.

Okay, I ran out to the shop and Spazola and I just measured a piece of scale from the floor by the big hammer. I specifically use methods to reduce scale formation so we're already discussing a variable that may not hold true for other shops. This also means that in my shop this is a conservative estimate of scale loss. The pieces of scale measured in the caliper average 0.005 inch thick.

Now, scale loss is a four sided effect on a billet. To be even more conservative, we only calculated the scale loss from two sides of the billet, the sides that will be exposed to the atmosphere, not the side between slabs being welded and not the sides that are not (which would double the amount of scale). 2 x 0.005 inch = 0.010 inch x 30,000 = 300 inches of material loss by the time you get to 30000 folds. All of us here today think the math is correct, but if it's not I'll agree to a change in the answer. And that's only two sides. It will go faster adding the remaining two sides in, or adding in less controlled forge operations/processes.

A 300 inch thick piece of steel is much more than I could lift, and I don't have a forge big enough to hold it. A 1.18 diameter bar 12 inches long weighs 4.8 pounds. Multiplied by 300 that's 1200 pounds roughly.

In the end, much better information produces less myth and magic. It also takes time to accumulate.

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Yeah I know what you mean, there is a great documentary on the history of the samurai sword. In the documentary it said that they understood adding charcoal to the iron made it much stronger but had no idea what carbon actually was. That these ancient blacksmiths were more like alchemist in a lot of ways. What I found really found interesting was the religious myth surrounding the sword, like every sword had a living breathing soul of its own. A psychologist on the show said that the neat thing about their sword having a soul was that when a samurai killed someone, the sword was to blame making it easier on the conscience.

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Originally Posted by Mike Blue

Several of the points you discuss beg to be refuted. I'll take on two since I'm trying to get ready to teach this stuff tomorrow. I wish you could be here.

Katana, made in Japan, are forged from tamahagane built into a billet of oroshigane then forge welded. No sword has ever been folded 30K times. The carbon content of tamahagane is 1.4-1.6% as smelted. By the time the billet has been forged into a blade the carbon content is reduced to between 0.6-0.7% depending on the particular sword school the smith attended. Forging a katana does not add carbon into the steel.


This does not mean that the smith does not understand how to add carbon to low carbon irons. The techniques to add carbon to irons are several. Attempting to add carbon from organic ashes is considerably less efficient than simple adjustment of the atmosphere of the forge and taking the time to allow the carbon to diffuse into the iron and considerably less efficient than packing the iron in a closed atmosphere box containing sources of carbon and preventing the carbon from binding to oxygen, its preference to iron.

The rest of the essay needs as much work. At least give eHow credit for most of your citations.

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Maybe the confusion is the term should be Layers, not folded.

If you take a piece of iron and fold it 16 times you get over 30,000 layers.

I should have read the other posts first.

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Originally Posted by Crotalus

Maybe the confusion is the term should be Layers, not folded. ...

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I hoped to emphasize that point. Myth and magic can be very entertaining but are often based on coincidental observations. Separating those things from how things really work is equally interesting, and easier said than done sometimes. Either perspective should eventually lead to understanding and accepting the other if the minds are open in between.

And now I know it is my razor's conscience that is responsible for nicking me. :)