[Whiggamore]

My understand is that Silver Steel has a carbon content of 1% to 1.2%. I also understand that carbon content beyond .86% (is it?) was unnecessary. The steel can't 'absorb' it, correct?

If that is the case, why does Silver Steel have such a high percentage of carbon? Do the other elements in the metal change this quality of carbon 'absorption'?

Also, does anybody 'spheroidize' their steel before working with it?

Edit: I forgot the point. How does Silver Steel differ from Carbon Steel as far as manufacturing a blade is concerned? Anything that one should be aware of?

[Russel Baldridge]

There will surely be some more in-depth responses, but the quick answer to the question about excess carbon is that it forms into carbides that are more wear resistant than plain steel. Simple carbon steel with excess carbon forms iron carbides, stain resistant steels can form chrome carbides because of the chromium content.

So more carbon is said to extend the edge holding abilities of the steel, but it makes for more complicated heat treating to dissolve the carbides.

As for spheroidizing, most steel producers offer steel in the spheroidized annealed state, but it is a process that requires pretty specific temperature controls, so most smiths do not re-spheroidize a piece of steel after work begins on it.

[JoshEarl]

One thing I'm hoping to learn when I'm able to get all these razor samples analyzed is whether carbides are a helpful thing to have in a razor blade at all.

The "carbides = better edge retention" formula is carried over from the knifemaking realm. It makes sense there, because hacking through highly abrasive stuff like rope requires an edge that is toothy.

At the levels of sharpness we're considering with razors, does a steel with lots of carbides really take and hold a better edge? I'm not sure.

They do definitely make the blade harder to hone. I'm still undecided on whether the extra honing difficulty has any payoff in terms of retention of a shaving edge.

As Russel hinted at, spheroid annealing is a bit complicated. Basically it involves heating the steel to a specific temperature and holding it there for hours or even days, then cooling veeeeeery slowly. If you do a traditional lamelar anneal with O1, for example, you get a semi-hard steel that is still pretty difficult to work. A spheroidized piece of O1 drills like butter.

Josh

Originally Posted by Russel Baldridge

There will surely be some more in-depth responses, but the quick answer to the question about excess carbon is that it forms into carbides that are more wear resistant than plain steel. Simple carbon steel with excess carbon forms iron carbides, stain resistant steels can form chrome carbides because of the chromium content.

So more carbon is said to extend the edge holding abilities of the steel, but it makes for more complicated heat treating to dissolve the carbides.

As for spheroidizing, most steel producers offer steel in the spheroidized annealed state, but it is a process that requires pretty specific temperature controls, so most smiths do not re-spheroidize a piece of steel after work begins on it.

[JimmyH-AD]

Years ago I was an ironworker and was working building kilns, ball mills and a clinker cooler at a cement plant. The clinker cooler receives pellets of cement that are called clinker at that stage and cools them from 2.000 to 200 degrees.

The cooling plates were made with 304 stainless. I asked the engineer back then why and he said that they used stainless because it is more abrasion resistant. These plates are kind of like swiss cheese and move to and fro as they receive the marble size pellets and as they cool they are sifted. This is very abrasive.

Having found stainless pocket knives much harder to sharpen then carbon blades this cleared up that mystery for me. I haven't decided if in my limited experience.stainless holds an edge longer. I know that it certainly is harder to sharpen with the abrasion resistance. It would be interesting if you made a blade forged and tempered to have less carbides and see how it would sharpen and how long it would hold an edge.

[metalhead]

ok im just learning with razors but i can give some what of an opinion on this. carbon steel is easier to sharpen and holds the edge for a decent amount of time. when it comes to stainless it depends on the grade of the steel low grade stainless is a pain in the ass to sharpen and dulls very quickly pretty much as soon as you cut something. about the best that i hve found is 440 stainless/surgical it takes forever to get a good edge but it holds very well. i have a dagger made from this grade i love and hate when totaly dull it takes me around 30 min to a hour to get an edge that will shave my arm with ease. and with regular use i wont have to put it back to the stone for about a month. regular use involves whatever i need a knife for at work . so i use it pretty regularly. jjust so you knnow i work in a woodworking shop

[Mike Blue]

In the end, the best performance from any steel requires that it be heat treated correctly for that steel. Even then, some steels will out-perform others.

Enough carbon to get hard is the first requirement. More carbon and the selective addition of alloying elements produces several effects, notably abrasion resistance. This is more function of reducing the wearing away of the blade and does improve edge retention by increasing the resistance of the wire edge to degradation. Other alloys like chromium at low levels will improve carbide formation and toughness to some degree depending on heat treatment and at high levels will increase corrosion resistance at the risk of reducing toughness.

Once enough knowledge developed to allow the various smiths to play with carbon and alloy contents, everyone had their own secret recipe for what was best. Now the industrial science types have rapidly acclerated us all beyond what was before, perfectly good performance, into potential excellence. I say, pick a steel you like, get really good at heat treating it consistently with the simplest setup that works well, learn to grind or hone them until they just wipe the hair off and stick with that. Chasing off after wunderstahl or unobtainium is a fickle pursuit.

In the end, it will come down to the edge and how it feels on the skin to the buyer.