chiral.grolim
Universal Kydex Sheath Extension
- Joined
- Dec 2, 2008
- Messages
- 6,422
Ok, heres my next question. Apart from the obvious rust protection, what dos stainless steel give you as opposed to non stainless or vice versa?
Here is another good read from Crucible's website, though it doesn't mention stainless steels specifically: http://www.crucibleservice.com/eselector/general/generalpart1.html
Stainless steels usually accomplish their corrosion resistance via chromium content, but chromium is a potent carbide former - i.e. it bonds with carbon in the steel to form hard particles - so the steel must contain sufficient chromium to leave some of it free in the matrix, 14-15% by most estimates. How much chromium is free depends on carbon content, other carbide-formers present, and also heat-treatment.
But of important consideration when comparing the properties of stainless vs non-stainless steels beyond that corrosion-resistance is the chromium carbide content. Chromium carbides are harder than ferric carbide (or ferrite, most often super-saturated with carbon to form martensite in knife steels) lending improved wear resistance. However, the most common form of chromium carbide in knife-steel is not its hardest form but a fairly large form. Large carbides do not bond as well to the steel matrix and also tend to form aggregates that can severely lower the impact toughness of the steel at high hardness, i.e. "brittle", and also increase the working apex-diameter of the steel preventing it from maintaing a very fine razor's edge. For this reason, stainless steel in "hard use" tools is left softer or geometry is thickened to improve structural support. HOWEVER, certain stainless steels feature very clean composition that, when properly HT'd, produce very small carbide grains (<1 micron), and manufacturing newer powder steels allows better distribution of the grains (to prevent aggregation) to maintain small size (<10 microns). These features improve impact toughness & wear resistance (e.g. compare CPM154 to 154CM), and allow for a longer-lasting razor's edge.
N690 vs O1? http://zknives.com/knives/steels/steelgraph.php?nm=BO1,N690&ni=152,521
My guess would be that O1 has higher attainable hardness or toughness but lower wear-resistance and corrosion resistance, and honestly the corrosion resistance is probably the most noticeable difference ... and the price.