Thread: Stainless Steel Hardness

I would like to ask if the stainless steel blades are harder or less hard than the non-stainless blades.
Adding chromium makes the steel more hard or less hard?

Thank you.

Having honed both I didnt notice a difference between carbon and SS. They both felt the same on the hones and both shaved the same.

Arguably the SS wont rust as fast, but it will still rust if you dont look after it. Thats about the only difference I can think of. The SS wasnt any harder or easier to hone than carbon IMO.

Have you ever noticed any difference in the capability of the blade to maintain the sharpness of the edge?
If one is harder than the other, then it should maintain the edge for longer.

I was told that adding chromium at about 12-14% to produce a stainless steel makes the blade less hard and therefore more prone to edge deformation. And that is the reason for the preference of non-stainless steel for making the most razors.

But I am not sure if it is actually true or not.

Originally Posted by Slur

I would like to ask if the stainless steel blades are harder or less hard than the non-stainless blades. Adding chromium makes the steel more hard or less hard?

+1 for what Stu mentioned. Hardness is a quality that is the same no matter the steel. A Rockwell C scale 60 is the same for either carbon or stainless or ultra high alloy modern wunderstahls.

Chromium increases the stain resistance but will not increase the hardness by itself. Hardness is something that occurs in the heat treatment. Chromium will change the temperature curve necessary to achieve a specific hardness, as do all alloying materials. Chromium is such an aggressive carbide former that it has been a contributor to brittleness in some stainless steels.

It is difficult for me to believe that two different alloys have exactly that same hardness, and that the strength of the blade depends only on the heat treatment.
It is more likely that two different alloys have different hardness when both undergo the same heat treatment.

I think the issue is, as it applies to a razor. If I'm not wrong Stainless Steel is just a name and is part of a series going from Chrome Steel to Nickel steel. I'm sure if you took a bar of two alloys and put them in a machine and deformed until they failed the performance would be different but when we talk about razors I agree with Mike. Personally, I have several Stainless Razors and there is no huge difference between Carbon and Stainless. Sometimes the stainless will take a wee bit extra to hone and give you a few extra shaves but then again I have Carbon razors that are way harder to hone than any Stainless Razor and shave longer than any stainless between touchups.

Hardness is different than toughness or ductility. Many things can have the same hardness, but different ductility or toughness. Cast irons are "harder" than many steels, but are not able to be sharpened like steel because they are brittle. SS may be harder to hone because the alloying elements make then more "gummy" as compared to 1095 steel. Most high carbon steels (above .65% C) will harden to a higher rockwell hardness than the bset, hardest SS. Typically, the higher the carbon content (to a point) the more the abliity of a steel to be hardened to a higher rockwell hardness number.

Originally Posted by Slur

It is more likely that two different alloys have different hardness when both undergo the same heat treatment.

That is exactly what Mike said:

Originally Posted by Mike Blue

A Rockwell C scale 60 is the same for either carbon or stainless or ultra high alloy modern wunderstahls.

Chromium will change the temperature curve necessary to achieve a specific hardness, as do all alloying materials.

If you HT to the same hardness, they will be the same hardness. But you will have to do different HT to get them to the same hardness - AKA if you do the same HT you get different hardnesses.

Mike also noted that other properties, besides hardness, come into play. That is important to keep in mind. In other words, the strength of the blade DOES NOT depend only on the hardness/HT.

Mike really knows his metal, so you really should read his posts carefully.

I was going to offer some pithy opinion, but then I realized that my emoticons are gone. Now I'm bummed and as a result the wealth of wisdom I was about to bestow just suffered a significant recession. Not all change is progress, I'm afraid.

Aha! That quick reply button to stiffle creativity does it again.