Why the Kizlyar Supreme Bastardo is a Great Knife.

 Why the Kizlyar Supreme Bastardo is a Great Knife.

In short 420HC ranks extremely high for toughness. What this translates to is total confidence that one is never going to break their precious wilderness knife, a knife which your life and those of others may well depend upon!

420HC does not loose it's corrosion resistance at maximum hardness. 420HC is also easy to sharpen. These features are great for a real working knife. Kizlyar Supreme are heat treating their 420HC to a maximum of HRC 58. Yes this is totally possible.

Here we can see (data provided by the manufacturer, Böhler) that the maximum HRC is around HRC 57.5, ie HRC58 can be obtained with little to no tempering. The toughness is achieved intrinsically from the alloy itself.

This data for Böhler N540 which is the same as AISI 420.

(note: probably not a very good idea to stick a N540/420HC blade in the fire.

YES, this isn't a high end steel but then again this is the steel of choice for a corrosion resistant blade that will be used everyday and must be easily sharpened without diamond tools.

To be honest when i first received this blade I was very sceptical of it's outdoor performance, especially at being able to stay sharp, even over a period of ONE day in the wilds cutting through solid oak logs and solid beech timber. I was super confident it would have a dull edge after a few minutes workout on this dirty (bark on) timber.  I had to swallow my ridiculous and scientifically unfounded prejudices about 420HC.  The thing about 420HC is it is crucial what is in the mix in terms of maximum limits of each batch. By this I mean the top of the bell curve for maximum allowable alloying elements because it has been also shown that the presence of Nitrogen in some variants lends itself to higher quality end products. I don't know what % of N is present in the alloy that Kizlyar Supreme is using but all I can say is that in real life catting tasks, this blade is making my very much more expensive knives look crap! (yes is is 420HC, I haven't made a mistake, as they also produce this blade with Sleipner tool steel).

Extrema Ratio RAO Steel

Out hiking

Here's a quick video run down of the Extrema Ratio RAO STEEL made with a Nitrogen Alloy steel.

                             

Out hiking (day hike)

Checking for  fat wood- yep a "positive"!

Let's not get confused with terminology Subject matter Teflon.

 

Teflon

The name "Teflon" conjures up immediately Teflon coated cookware. Nowadays many other metal objects are "Teflon coated" for either aesthetic reasons or technical purposes. 

However, these coatings are not exactly the same as the machinable plastic (virgin unfilled)  known as Teflon PTFE (Polytetrafluoroethylene). A naturally white (in the un dyed state), soft, low friction plastic, resistant to heat and chemical attack by all but the most aggressive compounds such as Fluorine gas. It has been in use in the laboratory workspace for a great many years for a myriad of things required to be heat and chemical resistant and also in high temperature high voltage electrical insulators within high voltage tanks.

Polytetrafluoroethylene

otherwise known as:

Poly (1,1,2, 2-tetrafluoroethylene)

Where "n" are the number of subunits

This  is "pure" form of Teflon as it will not bind to metal in this form.

Now, as I will mention the word "Teflon" here many times it will be in reference to any chlorinated fluorocarbon which has been applied to the metal surface via some sort of spray painting followed by oven baking to finalise adhesion to the metal surface and also to produce a homogenous polymer finish to the surface in question. Remembering "Teflon" is simply a trade name which can be addressed to numerous  fluorocarbon based products.

So let's talk about the features of coating a blade with a Teflon type coating. The first thing which comes to mind is the reduction of friction when cutting, particularly man made objects such as plastics and rubbers. 

For example:

Trying to puncture a tire will go horribly wrong if one can not extract their tool in a hurry nor for that matter insert it to begin with. A Teflon coating on a knife blade will certainly aid in this sort of operation.

Many materials (man made) will not stick permanently to the surface of such a coating and can thus be easily removed either by simply wiping, if no water (as a common solvent) is available or  simply using water, or a mild solvent or detergent. 

 Since  most Teflon coatings are proprietary and by default these chemical formulations and technical data for application is not available to the end users, therefore, it is not possible to determine the full chemical resistivity  range, however it's probably safe to say that whatever chemical one can throw at such coatings, they will be resistant against such attack (with the exception of extremely aggressive compounds or gases, as mentioned above . 

Since these teflon type coatings can be available in many colours, this is a huge bonus again for a military knife where the coating must also function as an anti- glare coating so as not to reveal your location.

Good Teflon coatings are exceptionally strong and resistant to abrasion and more importantly impact forces. A good coating must also resist removal from the metal surface. Finally a good coating will help to slow the effects of corrosion if that coating is applied to a semi stainless steel or even stainless steels which have been heat treated to above HRC 58 as these types of steels in general will loose some of their corrosion resistance the less Chromium there is in solid solution. ie if Chromium is tied up in carbide formation then there will simply be less functioning in corrosion protection. Speaking of corrosion protection even 8% Cr will help to provide corrosion protection (for uncoated blades). Not to mention if the surface finish is smooth and free of defects, even a mirror finish will always be the better option for corrosion resistance.

@BCT